Lizards:
Listed under the order, Squamata, which also includes snakes and amphisbaenians, the rather large lizard group comprises the suborder, Lacertilia, which is being pushed to be changed to Sauria. Currently there are around 3,800-4,765 species with 19 families, but stick around, this changes frequently.
Though lizards are in abundance in the tropics and numerable in temperate zones, their range extends beyond the Arctic Circle to the tips of South America, Africa and Australia. The United States is filled with 115 species of lizards spread under eight families which include the only two true venomous lizards. Strangely though, in NW Pennsylvania where I reside, there are no lizards. In fact, there are only four species, the eastern fence lizard and three skinks that call the state home at all. Three of these Pennsylvanian lizards are even considered threatened as two of them are listed as species of special concern with the remaining one as a candidate of concern.
Typical lizard characteristics are reptilian tetrapods with external ears, movable eyelids and a long tail. Also, lizards in general have excellent near vision, including color and night vision. However, there are no true distinguishing features unique to lizards and as always there are exceptions to their typical physical traits. Many lizard families contain legless forms, such as: Anguidae, Gerrosauridae and Gymnophthalmidae. Most geckos have no movable eyelids, with the gecko genus, Nephrurus having no more than a knob for a tail. To top the exception rule off, all 22 species members under the family, Dibamidae are legless, have no external ears, are basically blind and have a very short tail.
Size is diverse among this reptile group, ranging from the diminutive 29mm/1.1in chameleon, Brookesia micra that is no larger than a match head, to the dragon-sized varanid, Varanus komodoensis surpassing lengths of 3m/9.9ft.
Though lizards are in abundance in the tropics and numerable in temperate zones, their range extends beyond the Arctic Circle to the tips of South America, Africa and Australia. The United States is filled with 115 species of lizards spread under eight families which include the only two true venomous lizards. Strangely though, in NW Pennsylvania where I reside, there are no lizards. In fact, there are only four species, the eastern fence lizard and three skinks that call the state home at all. Three of these Pennsylvanian lizards are even considered threatened as two of them are listed as species of special concern with the remaining one as a candidate of concern.
Typical lizard characteristics are reptilian tetrapods with external ears, movable eyelids and a long tail. Also, lizards in general have excellent near vision, including color and night vision. However, there are no true distinguishing features unique to lizards and as always there are exceptions to their typical physical traits. Many lizard families contain legless forms, such as: Anguidae, Gerrosauridae and Gymnophthalmidae. Most geckos have no movable eyelids, with the gecko genus, Nephrurus having no more than a knob for a tail. To top the exception rule off, all 22 species members under the family, Dibamidae are legless, have no external ears, are basically blind and have a very short tail.
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| 1. Nephrurus levis ~ knob-tail |
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| 2. Dibamus dalaiensis |
The first known reptile was Hylonomus, appearing in the fossil record 315 mya. From this point reptile species diversified with one branch known as the Eolacertilia that were the earlist fossil lineage leading to Lepidosauromorpha. Evolving from lepidosauromorphan reptiles, primitive lizards first made their appearance during the Upper Triassic some 215 mya. From these basal lepidosaurmorphans, three crown subgroups appeared during the Middle Jurassic that led to three of the four extant lizards found today and are known as Anguimorpha, Gekkota and Scincomorpha.
Anguimorphs are a large group that includes, among others, today's alligator lizards, Gila monster, glass lizards and monitors. One anguimorph group that is now extinct are the marine mosasaurs. Geckos originated from Gekkota and skinks found their lineage through Scincomorpha.
The fourth extant group of today's lizards did not appear until the Lower Creataceous when the crown subgroup, Iguania first occurred. This group contains the iguanas. All other lizard groups became extinct by the end of the Creataceous.
One eolacertilian that was not in direct lineage, but was a close relative to the evolving lizards was Icarosaurus. A small animal in being no more than 10cm/4in from skull tip to hips, but with wings made of skin membrane supported by extended ribs, could effortlessly glide short distances in the Late Triassic cycad forests 228 mya. The extant lizard Draco, though only distantly related to Icarosaurus, glides today basically in the same way.
It would be worthwhile in mentioning here that for a period since its discovery in 2006, the fossil remains of Tikiguania estesi was widely thought to be the oldest representative of lizards. It was found in Triassic strata dating back to 220 mya. It was indeed found in Triassic material but it turns out that it was eroded material that was subsequently laid down over the exposed Triassic strata during the Miocene some 10-5 mya. The fossil material was washed onto the Triassic sediment then covered over and geologically recently eroded again exposing the fossil. The fossil is almost identical to the modern-day agamid lizards.
Originally, all lizards were carnivorous. Today, there are omnivorous lizards and 3% are true herbivores, such as iguanas, although insects will be ingested that were on any plant material the lizard eats. The oldest known lizard herbivore was discovered in 130 million year old Cretaceous sediment in Japan. The remains have been named, Kuwajimalla kagaensis. Current day terrestrial herbivore lizards dine on soft plants and in particular angiosperms (budding & flowering plants). They are restricted to a softer plant diet due to their fragile dentition (teeth). K. kagaensis had the same dentition. This poses a bit of a dilemma due to the fact that angiosperms only show up in the paleobotany record 125 mya, five million years later. So what did herbivore lizards munch on 130 mya when most plants of that period were tough and harsh? Perhaps, the angiosperm record goes back further, but just hasn't been discovered yet. Or just maybe, the tough tissue produced in guarding against all the big plant munching dinosaurids, when plant tissue was young or in sapling form, it was much softer making it more palatable for the lizard.
The diet of carnivorous lizards range from insects, other reptiles, rodents, birds, eggs and even wild goats and deer when it comes to the Komodo dragon, while the herbivores eat flowers, leaves and fruit. A sticky tongue and biting are the mode of acquiring and ingesting food. A few are true omnivores.
Lizard size is diverse and ranges from the recently discovered minute gecko, Sphaerodactylus ariasae reaching an adult SVL of only 1.6cm/0.63in and once again, to Varanus komodoensis that may reach a length in excess of 3.03m/10ft.
For obvious reasons in not benefiting fossorial blind lizards, but for most, sight is the most important sense. It is what they primarily use in seeking prey, alluding predators and communicating among each other. Most lizards see very well in visible light, detect UVB and their color vision is excellent. Due to this, many lizard species, such as anoles have developed colorful dewlaps, while some have multi-colored bodies, others can change their body color in an instant. Hearing and smelling are also well developed and utilized.
Chameleons have the ability to change color due to specialized chromatophore cells containing various colored pigments, such as xanthophores, iridophores and melanin. Chromatophores are located in three tiered layers holding their own color pigments just below the transparent top layer skin. Once the subconscious brain sends signals of color change, dispersion of color pigments commence and their particular arrangements give the chameleon's body its new color
pattern through reflection and refraction of light by the specific pigment alignment.
As mentioned earlier there are only two true venomous lizards, the Gila monster and the closely related Mexican beaded lizard with both ranging in Mexico and the arid southwest of the United States. Recently though at the University of Melbourne in Australia and Pennsylvania State in the USA, research reveals that iguanas and monitors possess in their oral cavity a pair of venom glands that produces an array of venoms collectively called toxicofera.
These venoms are very similar chemically to snake venoms, but are not administered through fangs; instead through chewing action as the helodermatids (the Gila monster and Mexican beaded lizard) do. This is not too surprising as recent DNA studies show a genetic relationship of anguimorphs, iguanas and monitors to snakes, which points to a common ancestor.
In particular in the bite of monitors, bacterial infection is the main concern, as many toxic bacterium in high culture amounts reside in these lizards' mouths. The venom appears to be in very low concentrations so there is no danger in killing an animal as large as a man, however swelling and excessive swelling may occur as a result of a venom flow into the wound. Even the chewing bite and induction of venom of an helodermatid is not enough to be lethal to a normal healthy adult, but their bites are still the most detrimental among lizards. With a vice-like jaw grip and grooved teeth to guide the venom into the wound, helodermatids are more specialized in introducing their GTX neurotoxin into the wound in greater concentrations.
Lizards share common traits with snakes such as having the lower jaw not joined directly to the skull, possess scales, have a paired hemipenis in males and a chemosensory organ (Jacobson's or vomeronasal where ducts connect the paired organs directly to the nasal cavity) in the mouth for molecular odor detection. Unique among lizards is that the jaws are less flexible than snakes and have an integumentary system comprised of scales which cover the external chordate body with the skull composed of quadrate bones.
Lizards set up home living on the ground surface, dwelling in trees, in burrows below the surface or spend most of their active time underwater only to come out onto the beach to rest. No matter where they live though, eggs are laid in the ground. Most are oviparous normally laying the typical leathery reptile egg, but some like, Gekko petricolus lay hard shelled eggs in the crevices of rocks, while others like Gekko gecko lay very soft shelled eggs that stick to what they were laid on while hardening through air exposure. A few in colder climes such as in Eurasia are viviparous. Although females of some skink species will often return to a nest to warm her eggs, virtually all young lizards just hatched or born are fully developed and must defend on their own from the outset.
Defenses are swift running, aggressive biting, bacteria ridden saliva, venom, tail autotomy, body spiking, cryptic camouflage, gliding, loosened nuchal skin frills to appear larger and squirting foul blood from the squeezing of frail eye vessels.
Under the order, Squamata, the current lizard suborder, Lacertilia is further divided into five infraorders. They are: Iguania with three families, Gekkota with three families, Scincomorpha with seven families, Diploglossa with three families and Platynota containing three families.
Texas Horny Toad
Family: Phrynosomatidae
Genus: Phrynosoma
Species: Phrynosoma cornutum
Length: 6-10cm/2.25-4in SVL; record: 18.1cm/7.13in
Weight: 24-36g/0.85-1.30oz
Longevity: 5-8yrs
Name Origin: Phrynosoma cornutum ~ Phrynos & soma are both Greek meaning 'toad' & 'body' respectively; cornutum is Latin meaning 'crowned' in reference to this lizard's horned head; altogether refers to the 'toad-bodied horny-headed lizard'.
Distribution: Although it has disappeared in east & central Texas and is decreasing in the southern & western portions of Texas, there still remain stable populations in northern Texas; as such this horned lizard is the officially recognized state reptile of Texas; populations elsewhere range from Colorado to Kansas, down into northern Mexico and westwards from New Mexico to southeastern Arizona; there are reports of isolated, but stable populations that were introduced in N. & S. Carolina, Georgia and northern Florida; also is possibly native to Arkansas and western Louisiana; prefers sandy areas near harvester ant mounds in grasslands, prairies, scrubland and deserts.
Description: In Texas, this lizard is referred to as a 'horny toad;' except during breeding season, this lizard is neither horny nor a toad, so in publications for obvious reasons, is referred colloquially as the 'horned lizard'; this description is much more accurate; P. cornutum possesses a forehead crest with 2 spikes, a neck frill ending in 2 spikes on each side with 2 large spikes in the center that look like horns; the dorsal surface is adorned with smaller spikes, also with 2 row sets running down each side of body ending at tip of tail; head spikes are part of skeletal structure, while body spines are attached to skin; has keeled non-mucronate (not sharp tipped) ventral scales; body is dorsolaterally flattened held up by short legs; dorsum coloration is tan or gray with random white & red or dull yellow markings; most specimens will also display black spot dorsal patterning corresponding where body spines erupt; ventrum is normally lighter in coloration,
darkening more as they grow; there are ~ 15 species of horned lizards in the genus, Phrynosoma and all can be easily recognized from their distinct spine arrangements on the head; populations of P. cornutum are specifically adapted to what its local habitat offers and has given way to genetically diverse isolated populations, however these genetically distinct populations are physically indistinct from one another in virtually appearing identical; for this reason, there are no current subspecies listed.
Diet: The diet is composed of 90% harvester ants with the remaining 10% occasionally supplemented by termites, small orthopterans such as crickets & grasshoppers, isopods (wood lice & pill bugs), beetles and their larvae; though adorned spikes create difficulties in swallowing this lizard, it still has many predators; birds (crows, bluejays, etc.) birds of prey (hawks, roadrunners) a variety of larger snakes, mammals (skunks, raccoons, opossums) and Onychomys torridus (grasshopper mouse) will take this lizard when detected, in particular juveniles by chewing the cranium around the orbit; numerous predators, such as shrikes will only get at and consume the internal organs.
Habits: In appearance, this lizard is right out of the film clips of prehistoric B movies; this mobile thorn bush has other defenses besides the body spiking; when sensing a threat will first lay flat to the ground where cryptic coloration camouflages the lizard to terrain surface; if the threat ensues, either will make a quick sprint or if cornered will elevate and inflate the body with air; if captured, has ability to squirt blood; blood squirting is accomplished by restricting blood flow leaving the head, thus rupturing tiny eyelid vessels sending the blood out in a stream; from consumption of harvester ants (Pogonomyrmex), it is believed formic acid taints the lizards blood making it foul tasting; blood squirting is a context-dependent display in which elicitation of the practice is conducted by judgement of predator type; larger mammals such as a kit fox (Vulpes macrotis) induce the judgement of lizard to squirt, if the fox has the lizard in the mouth, the taste of squirted blood will make the fox drop the lizard; all predators of this lizard exhibit care, if not usually suffer for it by choking to death in consuming the lizard whole as its horns lodge in the throat or experiences the foul taste
of the lizard's squirted blood abruptly ending an appetite; P. cornutum thermoregulates by angling body to most direct dawn sun rays to warm up and either seeks shade or burrows down into soil with sideways head shoveling with inflated body; is strictly diurnal seeking refuge during dark hours; conducts water harvesting by collection of water originally from air in form of humidity, dew & rain or soil moisture; is performed by developed features of skin where water spreads and is soaked into a capillary system in between scales; water is then transported to mouth where it is drunk; to hibernate, it burrows deeper into soil and remains in a torpid state not eating or drinking during cold months; emergence from hibernation is timed with harvester ant activity; after hibernation ends in late April, breeding commences; are oviparous and once internal fertilization has occurred, female will lay 12-40 eggs in May or June in a dugout chamber from
moist sandy soil, then cover eggs up and abandon the site; the flexible white eggs hatch in 45-55 days revealing miniature horned lizards around 3.2cm/1.25in long; neonates possess head spikes, but body is relatively smooth; upon hatching, neonates are on their own to defend and feed themselves; within 3 years juveniles are fully grown; no matter the age or size, this lizard does not attempt to bite in defense; though this species is in rapid decline in its natural range and is listed as threatened in the state of Texas, IUCN still list it as least concern; this lizard does not do well around human populated areas; the introduction of fire ants (genus: Solenopsis) exhibiting a competitive ferocity towards harvester ants along with pesticide decimation of harvester ants, this lizard's primary food, are reasons for this unique and docile reptile's decline.
Thorny Devil
Family: Agamidae
Genus: Moloch
Species: Moloch horridus
Length: 15-20cm/5.9-8in SVL
Weight: 70-95gm/2.5-3.4oz
Longevity: Up to 20yrs
Name Origin: Moloch horridus ~ Moloch is the name of an ancient Ammonite god who was offered child sacrifices and was portrayed as a god of evil in the Bible; horridus is Latin meaning 'dreadful' in reference to lizard's spiky appearance; altogether refers to, 'Moloch the dreadful lizard'.
Distribution: Is endemic to central Australia's arid terrain of triodia (indigenous hammock forming grasses), scrubland and desert; prefers sandy soils over rocky terrain.
Description: This lizard appears as a phrynosoma spp. on steriods considering the more numerous and larger spikes; though distantly and remotely related, both species developed morphological horned armor through convergent evolution rather than genetically; adapting to an arid habitat & climate, both species also share similar methods in what they eat and how they collect moisture to drink; M. horridus is a monotypic species within the genus, Moloch; evolving spikes as anatomically different from phrynosomids, M. horridus head spikes are composed of dermal keratin whereas phrynosomids head spikes are boney spines; dermal spikes envelope the thorny devil's body covering the ventrum as well with short sharp conical scattered spikes; body maintains long spikes & elongated scales protruding in every direction and in rows extending down back to tail; intermingled in between long pointed scales are dispersed small rhomboidal scales; head possesses a large horned knob on top of neck composed of stored fatty tissue; on the head, a small conical spike guards each nostril, while a large spike neighbored by smaller ones exist above each eye; displays sexual dimorphism with female generally larger and tends to be duller in color; also, males tend to be redder; overall color is dependent on temperature; when warm and active are a pale
yellow & red; when it is cold or threatened, turns more of a drab darkolive green; ventrum is color patterned much like the dorsum; hatchlings and neonate juveniles are black with white striping that turns more the adult's color as they age; although there is a concerted effort to discover even another distinct Moloch species, there are currently no subspecies.
Diet: Almost exclusively consumes ants; in particularly is partial to the small ant species, Iridomymex flavipes; if chanced upon, gut contents have exposed termite consumption along with ant larvae & debris ants most probably had carried when the lizard ate them, such as their grubs and plant matter; local raptors (bustards & sparrow hawks) and certain species of lizards such as the sand goanna (Varanus gouldi) and racehorse monitor (Varanus tristis) appear to be main predators; aborigines have and do also consume this lizard; thorny devils are usually heavily infested with nematode worms; Parapharyngodon & Abbreviata nematode species infect the intestines with lizard being infected as final hosts in eating their ant prey acting as intermediate hosts.
Habits: Besides weather affecting color change, the lizard has the ability to rapidly change color at any time by influencing reaction of pigmented dermal cells; are heliothermic relying on solar energy exposure to warm up and avoidance to cool down; leads a sedentary & solitary lifestyle and are not territorial; homesites are always near ant trails; during the summer & autumn months do not move no more than 6.1-9.1m/20-30ft away from their homesite; even in more active periods such as August-September (Australian winter & spring months) the lizards move no more than 76.2m/250ft from homesite; some thorny devils remain within 10.1m/33.33ft from where they originally were found 3 yrs ago; do not aestivate or hibernate, but will dig burrows or remain under shrub shade during hottest months of the year; are diurnal so are most active during daytime foraging for ants; on average will consume 750 ants per day, but sometimes up to 2500 ants may be consumed; once molecular energy and moisture has been collected from the ants in digestion, the ant exoskeletons are excreted as smooth surface fecal pellets; containing compressed ant parts, the pellets are spheroidal in shape; within homesite area thorny devils designate a latrine site and only go there to defecate; evidence indicates that these bathroom
sites are communal; once the lizard determines the latrine to be full, it will pick another site; like phrynosomids, collects moisture through capillary action generated by water's adhesion to tiny grooves in surface of scales, then moving interstitially through channels towards mouth; in addition, once a rare rain occurs, the feet can take up moisture embedded in the sand; besides body armor, elicits an array of predatory deterrents; if caught in the open by an encountered threat, the lizard performs a deliberate slow-motion walking-rocking gait; each leg first moves forward, then backward, then forward again essentially moving just one step; this is repeated many times until it feels it has reached a secure area; simultaneously in this 'start-retreat-start again' locomotion the tail is stiffened and held up; no one knows for sure, but this either confuses the predator or helps the lizard avoid detection by blending in more with the surroundings during slow gaiting; horny devils will also, like phrynosomids inflate extra air into the lungs appearing larger; if the head is touched, it will duck the head in between its shoulders making the neck hump appear as the head in possibly
avoiding a fatal head attack; breeding occurs during most active time in August & September when possible encounters increase due to increased locomotion; males will head bob or head but females then attempt to mount her; if female is not impressed, will reject the male mount by doing a rapid 360° spin, then leave after the male was ejected; once internal fertilization has occurred, female will lay a clutch of eggs once a year in late September to early December; clutches consist of 8-13 eggs laid in an orange-sized chamber excavated by the female; she digs a tunnel in the sand 30.5-61cm /12-24in, then right-angles the tunnel into a chamber; once oviposting has taken place she carefully covers the tunnel leaving an air pocket within the chamber; she finally disguises the tunnel surface by scraping the sand even then leaves; much effort is put into this egg chamber by simultaneously digging with both legs on one side, then switching to the other side in continuous repetition; in manufacturing, carrying, excavating and oviposting, female loses up to 40% of body weight consuming her stored fat; incubation period is 90-132 days depending on temperature of chamber; newly hatched neonates will eat their egg shells for calcium content, then dig through the filled tunnel in exiting to the surface; consumption of discarded eggs by M. horridus neonates is an unique trait not found in any other lizard; this first meal of egg shell supplies needed calcium; both juvenile sexes grow at the same rate for the first year, after that period females significantly outpace males; currently, this lizard is not threatened.
Scheltopusik
Family: Anguidae
Genus: Pseudopus
Species: Pseudopus apodus
Length: Up to 135cm/53.25in
Weight: 300-450gm/10.58-15.87oz
Longevity: 20-25 yrs in wilds; up to 50 yrs for well kept captives
Name Origin: Pseudopus apodus ~ Pseud is rooted in the Greek word pseudes meaning 'false'; opus is Latin for 'a need'; apodus, incorporated since 1871 is a misspelled derivative of the Greek word 'apodos' meaning footless'; altogether means 'footless lizard with a false need' in reference to lizard's tiny & useless hind feet.
Distribution: Including Russia, occurs in 17 European countries; also is found in Middle East & Near East countries; range is from the U.K. through the Balkans, along the Adriatic coast & Crimean coast, Caucasus, Transcaucasia & Central Asia; prefers lower altitudes of open woods, short growing grassy areas and loess soils with rocky outcrops and access to streams.
Description: Any layman's first encounter with this lizard would consider it a snake due to the similar body plan; closer inspection though, would reveal external ears, eyelids and rudimentary hind feet, all features not found in snakes; though this lizard virtually has no functional limbs, it is rather large and is the largest lizard in most of the countries it inhabits;
The common name, 'Scheltopusik' is Russian meaning 'yellow-bellied'; utilized in same fashion as snakes, has a bifurcated (forked) tongue that is flicked out to pick up air molecules sending them back to Jacobson's organ in roof of mouth for detection by scent; front half of tongue is very dark blue tipped; small palatine teeth present in a single row; rudimentary hind legs are 2-4mm/.08-0.16in and are adactylous (toeless) located at end of lateral furrow adjacent to cloaca; present are lateral furrows going down each side separating dorsum from ventrum; all scales are carinated in shape being most carina (ridge-like structure) distinct in caudal scalation; body scales are
connected to osteoderms and arranged in rings about the body; skin underneath scalation is quite hard containing a fair amount of chitinous material; sexual dimorphism is evident with male tending to be slightly larger, while males also have larger heads in being wider than body; female head width is indistinct from body; adult coloration for dorsal side is an overall general pale brown with darker brown displayed interstitially between scales; head is lighter brown with ventral side displaying a lighter yellowish tan brown; juveniles have a gray ventrum and very contrasting dorsal color patterns of brown shades that eventually begins to fade into adult coloration after 2-3 yrs; scheltopusik was previously listed under the genus Ophisaurus and transferred to the monotypic genus, Pseudopus although it has not fully caught on; currently 3 subspecies are recognized in P. a. apodus, P. a. durvilli & P. a. thracius.
Diet: P. apodus is an opportunistic and predaceous predator preying primarily on invertebrates, in particular gastropods (snails & slugs); also consumes a fair amount of insects and if opportunity presents itself will take small vertebrates such as frogs, lizards, snakes, shrews, rodents & birds; fruits in season from wild plants are taken as well; in captivity have been observed consuming presented eggs raw or boiled, but this certainly does not mean eggs are consumed naturally in the wilds; as varied as its diet is, the lizard also has to contend with an array of predators that prey on it; birds of prey, larger snakes and various carnivorous mammals.
Habits: Scheltopusik is a multitasking lizard in that not only can it display agility and sudden bursts of speed in reaching 5-10m/16.5-33ft in a matter of seconds on land, it is also exhibits arboreal adeptness at climbing and efficiently swims & dives remaining submerged for minutes at a time; smallness of pulmonary vessels permit this reptile to suspend respiration without arresting coursing blood during submergence; displays a form of intelligent behavior in captives being able to recognize and respond to handlers; two-thirds of total length consist of tail; belonging to the glass lizard group, it does have a tail that will break off, but the fracturing plane is not well defined for P. apoda and regeneration of a new tail is poor; due to this, under threat or harassment, this lizard prefers to twist, hiss and at times bite hard rather than
submitting to caudal autonomy; with conical serrated teeth, the dentition is well suited for cracking shells of its favored snail prey; prefers dry habitat, but after rains are particularly active due to optimizing contact with snails & slugs; is diurnal doing most of its activity during daylight, preferring to retire in rock or earth crevices or abandoned rodent burrows during darkness; though it will burrow through loose soil, is not fossorial; at dawn can be found on rocks or branches of trees or shrubs soaking up warmth of sun rays; in its colder range will hibernate from October to March and until May in the coldest climes; reinforcement of scales with osteoderms provides adequate protection, as many
scheltopusiks are found with damaged scales due to predator attacks, but nonetheless are unharmed and alive; breeding in the wilds takes place either in March or May, dependent when emerging from hibernation; after mating, the female retains her fertilized eggs for ten weeks then oviposits her 8-12 eggs in a suitable earth or rock crevice or under ground or ground debris such as a large piece of bark; she will remain at the nest site guarding her egg clutch until hatching in 45-55 days appearing from July to September; hatchlings are 10-15cm/3.94-5.9in; nourished from egg yolk, they begin feeding on their own after 4 days from hatching; after 4 yrs, young mature to become sexually active; though local populations are threatened and have decreased, due to tolerance of a wide range of habitat, it is currently listed as least concern.
Mexican Beaded Lizard
Family: Helodermatidae
Genus: Heloderma
Species: Heloderma horridum
Length: 61-101.6cm/24-40in (SVL)
Weight: 3.18-4.54kg/7-10lbs
Longevity: Listed as 30yrs but handlers have specimens over 50yrs & are still breeding
Name Origin: Heloderma horridum ~ Helos & derma are both Greek meaning 'head of a stud' and 'skin' respectively; horridum is Latin meaning 'rough', 'rude' or 'horrible'; altogether refers to, 'rough skinned horrible studded lizard'.
Distribution: From latitude 25, this lizard is found throughout western & central Mexico southward to Guatemala in northern Central America; prefers semi-arid rocky regions with ledges and sparse vegetation characteristic of Mexico's open forests, canyons and washes; found from sea level to 1500m/4,950ft asl; Heloderma spp. were once more widespread with Miocene fossils of 17.6-17.5 mya found in Florida, 20 mya in Texas and Oligocene fossils in Colorado & Nebraska from 30 mya;
Description: 2 extant helodermatid species exist with the other, Heloderma suspectum (Gila monster) being smaller and appeared in the geological record later, therefore it appears H. suspectum evolved from H. horridum; helodermatids possess a muscular mouth with strong jaw muscles to maintain a strong biting grip; conical pointed teeth exist in both lower & upper
mandibles; in addition lower mandible teeth have a groove from the base extending ~ 1/8 up the tooth; groove acts as a feeder line for hemotoxin; toxin is produced in modified salivary glands located in lower lips and transported through ducts leading to the base of lower mandible teeth; with a vice like grip, the lizard holds its bite then accelerates chewing action which begins to inoculate the flowing venom into the bite wound site; venom is primarily used in defense than in capturing prey; prey is normally small and easily subdued; adversaries such as birds of prey, coyotes and humans are much larger, thus a
defensive venomous and very painful bite gives leverage to the lizard's survival in thwarting encounters; known as GTX, toxin is composed of several peptides belonging to glucagon group; glucagon peptide hormones are secreted naturally from pancreas in living vertebrate organisms to lower blood sugar; how venom causes havoc is that it binds to exindin receptors of pancreatic acinar cells thus blocking inhibitory effect of lowering blood sugar levels; head is wide & flat while body overall is cylindrical in shape; legs are short but strong ending in feet with long recurved claws resembling eagle talons; skin over entire body is covered by pimpled protrusions called beads; each bead contains a tiny piece of bone known as an osteoderm giving an armor plated appearance; osteoderms do not overlap; bifurcated tongue is pink while H. suspectum has very dark blue tongues; tail is long and thick used for fat storage; some sexual dimorphism exists with males being larger and heavier and have thicker heads & necks; overall body coloration is dark brown to black with many pink, yellow and/or orange spotting; head, tail and limbs are normally overall black with tail in certain subspecies exhibiting paired lighter colored rings of yellow, orange or white; legs are often marked with lighter colors; there are 4 recognized subspecies; they are: Heloderma h. horridum, H. h. alvarez, H. h. charlesbogerti & H. h. xasperatum.
Diet: Primary food source are contents of buried, ground and arboreal eggs; diet is also supplemented with young prey of birds, reptiles and smaller mammals; predators are large raptorial birds, larger venomous and constrictor snakes, large Drymarchon corais, which is neither venomous or a constrictor and mammals such as coyotes & foxes.
Habits: This lizard is wholly carnivorous and is mostly crepuscular searching in twilight for its favored egg foods primarily from nests on ground or buried, but is not uncommon for it to climb trees and shrubs to locate nest contents; with strong muscled limbs, long curved claws
and semi-prehensile tail has arboreal traits; well adept in climbing trees or rocks; will at times sleep in trees or rock ledges; sleeps with limbs prostrate and ventrum fully on surface; when active appears as sluggish in movement; even eating is casually conducted; when threatened can react with lightning like reflexive speed; does not pursue mobile prey; uses keen sense of smell flicking tongue out to pick air molecules and transport them back into mouth for Jacobson's organ analysis; olfactory & vomeronasal senses are highly developed and is what aids in locating nest sites, even those buried; sight is used to consume nest contents; living off fat stored in tail can survive months without eating, but when food is available will gorge feed as much as stomach can hold; when threatened, will hiss with mouth open ready to bite; the bite is retained with a pugnacious muscular grip, though for humans the bite can be very painful
from the physical infliction along with venom that seeps into the wound, it is never fatal to healthy individuals; it is now known that a few other monitor lizards, such as the Komodo dragon (Varanus komodoensis) possess mouth orifice venom, but helodermatids are the only lizards to have evolved an overt venom delivery system; this lizard is a leisure feeder and shows no apparent hostile competition among each other if dining together; except for eggs, in which it breaks slurping out the contents, it eats its food whole; ~ 95% of time is spent resting and hiding in burrows, rock crevices, up to 6-7m/19.8-23.1ft in tree limbs or tree-hole shelters; possesses one of the highest sustained aerobic rates of any lizard; high aerobic activity is more pronounced in males than females and is most probably due to their wrestling during breeding season
in competition for breeding rights; mating begins from May to July in northernmost range and from September to November in southernmost range; males engage in wrestling matches during breeding season that can last up to hours at a time; during matches in process, males lever off ground with heads & tails forming an arch; from this position aim is to push opponent on his back onto the ground then bite the opponent on the mouth pinning jaws; competition is rarely if ever fatal for the loser and they are immune to the venom; the victor has sole rights to breed; the male mounts the female then begins rubbing his chin from side-to-side on top of her head; this causes her to submit where mating thus commences; copulation may last from several minutes to a few hours; gestation period for the
female is from 35-65 days; when ready to oviposit, usually in late autumn, female will find suitable ground site that is not too dry or damp to commence digging a hole, then lay her clutch of 2-30 oblong white eggs; once laying her last egg, maternal instincts are over; incubation is from 6-12 months; upon hatching, known as pipping (pip), neonate will usually stay near its egg absorbing its yolk sac for 2-4 days; once sac is emptied, normally rest of egg shell contents is then consumed; in 2.5-3 yrs. juveniles become sexually mature; though some subspecies are imperiled, overall H. horridum is considered as not threatened; should note here that H. h. charlesbogerti (Motagua Valley beaded lizard) is one of the most endangered lizard species listed worldwide with only a population of around 200; unfortunately, the critically endangered lizard species, Ctenosaura palearis' eggs are an important food source for H. h. charlesbogerti, thereby forming a link to both their threatened status.
Anguimorphs are a large group that includes, among others, today's alligator lizards, Gila monster, glass lizards and monitors. One anguimorph group that is now extinct are the marine mosasaurs. Geckos originated from Gekkota and skinks found their lineage through Scincomorpha.
The fourth extant group of today's lizards did not appear until the Lower Creataceous when the crown subgroup, Iguania first occurred. This group contains the iguanas. All other lizard groups became extinct by the end of the Creataceous.
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| 3. Icarosaurus lived 228 mya |
It would be worthwhile in mentioning here that for a period since its discovery in 2006, the fossil remains of Tikiguania estesi was widely thought to be the oldest representative of lizards. It was found in Triassic strata dating back to 220 mya. It was indeed found in Triassic material but it turns out that it was eroded material that was subsequently laid down over the exposed Triassic strata during the Miocene some 10-5 mya. The fossil material was washed onto the Triassic sediment then covered over and geologically recently eroded again exposing the fossil. The fossil is almost identical to the modern-day agamid lizards.
Originally, all lizards were carnivorous. Today, there are omnivorous lizards and 3% are true herbivores, such as iguanas, although insects will be ingested that were on any plant material the lizard eats. The oldest known lizard herbivore was discovered in 130 million year old Cretaceous sediment in Japan. The remains have been named, Kuwajimalla kagaensis. Current day terrestrial herbivore lizards dine on soft plants and in particular angiosperms (budding & flowering plants). They are restricted to a softer plant diet due to their fragile dentition (teeth). K. kagaensis had the same dentition. This poses a bit of a dilemma due to the fact that angiosperms only show up in the paleobotany record 125 mya, five million years later. So what did herbivore lizards munch on 130 mya when most plants of that period were tough and harsh? Perhaps, the angiosperm record goes back further, but just hasn't been discovered yet. Or just maybe, the tough tissue produced in guarding against all the big plant munching dinosaurids, when plant tissue was young or in sapling form, it was much softer making it more palatable for the lizard.
The diet of carnivorous lizards range from insects, other reptiles, rodents, birds, eggs and even wild goats and deer when it comes to the Komodo dragon, while the herbivores eat flowers, leaves and fruit. A sticky tongue and biting are the mode of acquiring and ingesting food. A few are true omnivores.
Lizard size is diverse and ranges from the recently discovered minute gecko, Sphaerodactylus ariasae reaching an adult SVL of only 1.6cm/0.63in and once again, to Varanus komodoensis that may reach a length in excess of 3.03m/10ft.
For obvious reasons in not benefiting fossorial blind lizards, but for most, sight is the most important sense. It is what they primarily use in seeking prey, alluding predators and communicating among each other. Most lizards see very well in visible light, detect UVB and their color vision is excellent. Due to this, many lizard species, such as anoles have developed colorful dewlaps, while some have multi-colored bodies, others can change their body color in an instant. Hearing and smelling are also well developed and utilized.
Chameleons have the ability to change color due to specialized chromatophore cells containing various colored pigments, such as xanthophores, iridophores and melanin. Chromatophores are located in three tiered layers holding their own color pigments just below the transparent top layer skin. Once the subconscious brain sends signals of color change, dispersion of color pigments commence and their particular arrangements give the chameleon's body its new color
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| 4. Chameleon ~ Furcifer pardalis |
As mentioned earlier there are only two true venomous lizards, the Gila monster and the closely related Mexican beaded lizard with both ranging in Mexico and the arid southwest of the United States. Recently though at the University of Melbourne in Australia and Pennsylvania State in the USA, research reveals that iguanas and monitors possess in their oral cavity a pair of venom glands that produces an array of venoms collectively called toxicofera.
These venoms are very similar chemically to snake venoms, but are not administered through fangs; instead through chewing action as the helodermatids (the Gila monster and Mexican beaded lizard) do. This is not too surprising as recent DNA studies show a genetic relationship of anguimorphs, iguanas and monitors to snakes, which points to a common ancestor.
In particular in the bite of monitors, bacterial infection is the main concern, as many toxic bacterium in high culture amounts reside in these lizards' mouths. The venom appears to be in very low concentrations so there is no danger in killing an animal as large as a man, however swelling and excessive swelling may occur as a result of a venom flow into the wound. Even the chewing bite and induction of venom of an helodermatid is not enough to be lethal to a normal healthy adult, but their bites are still the most detrimental among lizards. With a vice-like jaw grip and grooved teeth to guide the venom into the wound, helodermatids are more specialized in introducing their GTX neurotoxin into the wound in greater concentrations.
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| 5. Gila monster ~ Heloderma suspectum |
Lizards set up home living on the ground surface, dwelling in trees, in burrows below the surface or spend most of their active time underwater only to come out onto the beach to rest. No matter where they live though, eggs are laid in the ground. Most are oviparous normally laying the typical leathery reptile egg, but some like, Gekko petricolus lay hard shelled eggs in the crevices of rocks, while others like Gekko gecko lay very soft shelled eggs that stick to what they were laid on while hardening through air exposure. A few in colder climes such as in Eurasia are viviparous. Although females of some skink species will often return to a nest to warm her eggs, virtually all young lizards just hatched or born are fully developed and must defend on their own from the outset.
Defenses are swift running, aggressive biting, bacteria ridden saliva, venom, tail autotomy, body spiking, cryptic camouflage, gliding, loosened nuchal skin frills to appear larger and squirting foul blood from the squeezing of frail eye vessels.
Under the order, Squamata, the current lizard suborder, Lacertilia is further divided into five infraorders. They are: Iguania with three families, Gekkota with three families, Scincomorpha with seven families, Diploglossa with three families and Platynota containing three families.
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| 1. Texas horny toad ~ P. cornutum |
Texas Horny Toad
Family: Phrynosomatidae
Genus: Phrynosoma
Species: Phrynosoma cornutum
Length: 6-10cm/2.25-4in SVL; record: 18.1cm/7.13in
Weight: 24-36g/0.85-1.30oz
Longevity: 5-8yrs
Name Origin: Phrynosoma cornutum ~ Phrynos & soma are both Greek meaning 'toad' & 'body' respectively; cornutum is Latin meaning 'crowned' in reference to this lizard's horned head; altogether refers to the 'toad-bodied horny-headed lizard'.
Distribution: Although it has disappeared in east & central Texas and is decreasing in the southern & western portions of Texas, there still remain stable populations in northern Texas; as such this horned lizard is the officially recognized state reptile of Texas; populations elsewhere range from Colorado to Kansas, down into northern Mexico and westwards from New Mexico to southeastern Arizona; there are reports of isolated, but stable populations that were introduced in N. & S. Carolina, Georgia and northern Florida; also is possibly native to Arkansas and western Louisiana; prefers sandy areas near harvester ant mounds in grasslands, prairies, scrubland and deserts.
Description: In Texas, this lizard is referred to as a 'horny toad;' except during breeding season, this lizard is neither horny nor a toad, so in publications for obvious reasons, is referred colloquially as the 'horned lizard'; this description is much more accurate; P. cornutum possesses a forehead crest with 2 spikes, a neck frill ending in 2 spikes on each side with 2 large spikes in the center that look like horns; the dorsal surface is adorned with smaller spikes, also with 2 row sets running down each side of body ending at tip of tail; head spikes are part of skeletal structure, while body spines are attached to skin; has keeled non-mucronate (not sharp tipped) ventral scales; body is dorsolaterally flattened held up by short legs; dorsum coloration is tan or gray with random white & red or dull yellow markings; most specimens will also display black spot dorsal patterning corresponding where body spines erupt; ventrum is normally lighter in coloration,
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| 2. Ventral side |
Diet: The diet is composed of 90% harvester ants with the remaining 10% occasionally supplemented by termites, small orthopterans such as crickets & grasshoppers, isopods (wood lice & pill bugs), beetles and their larvae; though adorned spikes create difficulties in swallowing this lizard, it still has many predators; birds (crows, bluejays, etc.) birds of prey (hawks, roadrunners) a variety of larger snakes, mammals (skunks, raccoons, opossums) and Onychomys torridus (grasshopper mouse) will take this lizard when detected, in particular juveniles by chewing the cranium around the orbit; numerous predators, such as shrikes will only get at and consume the internal organs.
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| 3. Note head spikes part of osteology |
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| 4. Young roadrunner's fatal mistake |
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| 5. Typical Phrynosoma neonate size |
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| 1. Thorny devil ~ M. horridus |
Thorny Devil
Family: Agamidae
Genus: Moloch
Species: Moloch horridus
Length: 15-20cm/5.9-8in SVL
Weight: 70-95gm/2.5-3.4oz
Longevity: Up to 20yrs
Name Origin: Moloch horridus ~ Moloch is the name of an ancient Ammonite god who was offered child sacrifices and was portrayed as a god of evil in the Bible; horridus is Latin meaning 'dreadful' in reference to lizard's spiky appearance; altogether refers to, 'Moloch the dreadful lizard'.
Distribution: Is endemic to central Australia's arid terrain of triodia (indigenous hammock forming grasses), scrubland and desert; prefers sandy soils over rocky terrain.
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| 2. Lft: P.cornutum rt: M. horridus |
Description: This lizard appears as a phrynosoma spp. on steriods considering the more numerous and larger spikes; though distantly and remotely related, both species developed morphological horned armor through convergent evolution rather than genetically; adapting to an arid habitat & climate, both species also share similar methods in what they eat and how they collect moisture to drink; M. horridus is a monotypic species within the genus, Moloch; evolving spikes as anatomically different from phrynosomids, M. horridus head spikes are composed of dermal keratin whereas phrynosomids head spikes are boney spines; dermal spikes envelope the thorny devil's body covering the ventrum as well with short sharp conical scattered spikes; body maintains long spikes & elongated scales protruding in every direction and in rows extending down back to tail; intermingled in between long pointed scales are dispersed small rhomboidal scales; head possesses a large horned knob on top of neck composed of stored fatty tissue; on the head, a small conical spike guards each nostril, while a large spike neighbored by smaller ones exist above each eye; displays sexual dimorphism with female generally larger and tends to be duller in color; also, males tend to be redder; overall color is dependent on temperature; when warm and active are a pale
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| 3. Top: P. cornutum Bttm: M. horridus |
Diet: Almost exclusively consumes ants; in particularly is partial to the small ant species, Iridomymex flavipes; if chanced upon, gut contents have exposed termite consumption along with ant larvae & debris ants most probably had carried when the lizard ate them, such as their grubs and plant matter; local raptors (bustards & sparrow hawks) and certain species of lizards such as the sand goanna (Varanus gouldi) and racehorse monitor (Varanus tristis) appear to be main predators; aborigines have and do also consume this lizard; thorny devils are usually heavily infested with nematode worms; Parapharyngodon & Abbreviata nematode species infect the intestines with lizard being infected as final hosts in eating their ant prey acting as intermediate hosts.
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| 4. Dorsal view |
Habits: Besides weather affecting color change, the lizard has the ability to rapidly change color at any time by influencing reaction of pigmented dermal cells; are heliothermic relying on solar energy exposure to warm up and avoidance to cool down; leads a sedentary & solitary lifestyle and are not territorial; homesites are always near ant trails; during the summer & autumn months do not move no more than 6.1-9.1m/20-30ft away from their homesite; even in more active periods such as August-September (Australian winter & spring months) the lizards move no more than 76.2m/250ft from homesite; some thorny devils remain within 10.1m/33.33ft from where they originally were found 3 yrs ago; do not aestivate or hibernate, but will dig burrows or remain under shrub shade during hottest months of the year; are diurnal so are most active during daytime foraging for ants; on average will consume 750 ants per day, but sometimes up to 2500 ants may be consumed; once molecular energy and moisture has been collected from the ants in digestion, the ant exoskeletons are excreted as smooth surface fecal pellets; containing compressed ant parts, the pellets are spheroidal in shape; within homesite area thorny devils designate a latrine site and only go there to defecate; evidence indicates that these bathroom
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| 5. Note fat storage hump |
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| 6. Locomotion when threatened |
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| 1. Scheltopusik ~ P. Apodus |
Scheltopusik
Family: Anguidae
Genus: Pseudopus
Species: Pseudopus apodus
Length: Up to 135cm/53.25in
Weight: 300-450gm/10.58-15.87oz
Longevity: 20-25 yrs in wilds; up to 50 yrs for well kept captives
Name Origin: Pseudopus apodus ~ Pseud is rooted in the Greek word pseudes meaning 'false'; opus is Latin for 'a need'; apodus, incorporated since 1871 is a misspelled derivative of the Greek word 'apodos' meaning footless'; altogether means 'footless lizard with a false need' in reference to lizard's tiny & useless hind feet.
Distribution: Including Russia, occurs in 17 European countries; also is found in Middle East & Near East countries; range is from the U.K. through the Balkans, along the Adriatic coast & Crimean coast, Caucasus, Transcaucasia & Central Asia; prefers lower altitudes of open woods, short growing grassy areas and loess soils with rocky outcrops and access to streams.
Description: Any layman's first encounter with this lizard would consider it a snake due to the similar body plan; closer inspection though, would reveal external ears, eyelids and rudimentary hind feet, all features not found in snakes; though this lizard virtually has no functional limbs, it is rather large and is the largest lizard in most of the countries it inhabits;
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| 2. Note bifurcate tongue |
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| 3. Carinated scalation detail |
Diet: P. apodus is an opportunistic and predaceous predator preying primarily on invertebrates, in particular gastropods (snails & slugs); also consumes a fair amount of insects and if opportunity presents itself will take small vertebrates such as frogs, lizards, snakes, shrews, rodents & birds; fruits in season from wild plants are taken as well; in captivity have been observed consuming presented eggs raw or boiled, but this certainly does not mean eggs are consumed naturally in the wilds; as varied as its diet is, the lizard also has to contend with an array of predators that prey on it; birds of prey, larger snakes and various carnivorous mammals.
Habits: Scheltopusik is a multitasking lizard in that not only can it display agility and sudden bursts of speed in reaching 5-10m/16.5-33ft in a matter of seconds on land, it is also exhibits arboreal adeptness at climbing and efficiently swims & dives remaining submerged for minutes at a time; smallness of pulmonary vessels permit this reptile to suspend respiration without arresting coursing blood during submergence; displays a form of intelligent behavior in captives being able to recognize and respond to handlers; two-thirds of total length consist of tail; belonging to the glass lizard group, it does have a tail that will break off, but the fracturing plane is not well defined for P. apoda and regeneration of a new tail is poor; due to this, under threat or harassment, this lizard prefers to twist, hiss and at times bite hard rather than
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| 4. P. apoda tooth |
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| 5. P. apoda juvenile |
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| 1. Mexican beaded ~ H. horridum |
Mexican Beaded Lizard
Family: Helodermatidae
Genus: Heloderma
Species: Heloderma horridum
Length: 61-101.6cm/24-40in (SVL)
Weight: 3.18-4.54kg/7-10lbs
Longevity: Listed as 30yrs but handlers have specimens over 50yrs & are still breeding
Name Origin: Heloderma horridum ~ Helos & derma are both Greek meaning 'head of a stud' and 'skin' respectively; horridum is Latin meaning 'rough', 'rude' or 'horrible'; altogether refers to, 'rough skinned horrible studded lizard'.
Distribution: From latitude 25, this lizard is found throughout western & central Mexico southward to Guatemala in northern Central America; prefers semi-arid rocky regions with ledges and sparse vegetation characteristic of Mexico's open forests, canyons and washes; found from sea level to 1500m/4,950ft asl; Heloderma spp. were once more widespread with Miocene fossils of 17.6-17.5 mya found in Florida, 20 mya in Texas and Oligocene fossils in Colorado & Nebraska from 30 mya;
Description: 2 extant helodermatid species exist with the other, Heloderma suspectum (Gila monster) being smaller and appeared in the geological record later, therefore it appears H. suspectum evolved from H. horridum; helodermatids possess a muscular mouth with strong jaw muscles to maintain a strong biting grip; conical pointed teeth exist in both lower & upper
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| 2. H. horridum skull; note teeth |
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| 3. Note groove in tooth |
Diet: Primary food source are contents of buried, ground and arboreal eggs; diet is also supplemented with young prey of birds, reptiles and smaller mammals; predators are large raptorial birds, larger venomous and constrictor snakes, large Drymarchon corais, which is neither venomous or a constrictor and mammals such as coyotes & foxes.
Habits: This lizard is wholly carnivorous and is mostly crepuscular searching in twilight for its favored egg foods primarily from nests on ground or buried, but is not uncommon for it to climb trees and shrubs to locate nest contents; with strong muscled limbs, long curved claws
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| 4. Note claws |
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| 5. Adeptness at climbing |
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| 6. Neonate upon hatching |
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| 7. H. h. charlesbogerti |
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| 1. Chinese croc lizard ~ S. crocodilurus |
Chinese Crocodile Lizard
Family: Xenosauridae
Genus: Shinsaurus
Species: Shinisaurus crocodilurus
Length: 40-46cm/16-18in total length (TL)
Weight: 200-300gm/0.4lb-0.6lbs
Longevity: Unknown in the wilds, but possibly exceeds 10 yrs
Name Origin: Shinisaurus crocodilurus ~ Shini is in reference to Professor Shin of Sun Yat-sen University who discovered the reptile for science in 1928; saurus is modern Latin originating from Greek 'sauros' meaning lizard; crocodilurus is from Latin word, 'crocodilus' and is in reference to crocodile-like tail; altogether means 'Shin's crocodile-like lizard'.
Distribution: Is found in southern China's remote Guilin region in mountainous part of Guangxi (Kwangsei) Province at elevations between 500-700m/1,650-2,310ft; In 2003, a small isolated population was found in northeastern Vietnam; prefers thick overhang growth habitat along shallow and clear streams & pools with sandy or rocky bottoms.
Description: After intensive anatomical studies were conducted in 1954, S. crocodilurus was placed in the Xenosauridae family linking trans-Pacific xenosaurid forms together based on continental drift; due to unique scale surface conversion of S. crocodilurus during ontogeny of its habitat into higher elevations, there has been a big push since 1999 to classify this lizard species into its own monotypic family, Shinisauridae; It's your choice, but I prefer keeping it under Xenosauridae, under the subfamily, Shinisaurinae as it highlights evolvement from
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| 2. A male; note crocodile-like tail |
Diet: Is a generalist predator preying on anything that its habitat provides from insects and their larvae, worms, mollusks, tadpoles, small fish, frogs, arachnids and very small rodents; stomach content studies from this lizard reveal that caterpillars and aquatic dragonfly larvae make-up a considerable part of its diet; adult food intake is 10% of body mass per week; gravid female intake is 41%, while growing juveniles reach 57% body mass per week of food intake; main predation is from raptors, carnivorous mammals, while humans also consume this lizard.
Habits: This lizard is diurnal and can be found at anytime in water, on land near water or in bushes or trees usually no more than a meter/3.3feet of overhanging branches above water; likes basking in sunshine in overhanging branches or on a bank rock where it may jump into the water at first sign of alarm; tail propels the lizard through water; may remain submerged for over half an hour drastically slowing down respiration & metabolism as remaining motionless; when water temperatures drop below 15° C/60° F, the lizard will drown with metabolism shutting down; with short limbs and curved claws is adept at climbing; may remain motionless in tree limbs for hours at a time known as a metabolic pause, which suspends the animal from reacting even to encroaching threats; for this reason, indigenous Chinese call S. crocodilurus 'the lizard of great sleepiness'; this phenomena conserves calorie consumption,
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| 3. Favored hunting position |
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| 4. Consuming a frog |
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| 5. A neonate |
Vulnerable (3.1) IUCN |
| 1. Blue iguana ~ C. lewisi |
Blue Iguana
Family: Iguanidae
Genus: Cyclura
Species: Cyclura lewisi
Length: 50.8-76.2cm/20-30in snout-vent length (SVL); 1.5m/5ft total length (TL)
Weight: 14kg/30lbs
Longevity: In wilds 20-40yrs; a zoo captive named Godzilla in Brownsville, Texas lived 69yrs
Name Origin: Cyclura lewisi ~ Cycl & ura are ancient Greek derivitives from the words, 'cyclos' (circular) and 'oura' (tail) referring to thick ringed tail; lewisi is the Latinized form in honoring the scientist Bernard C. Lewis who first described this lizard in the late 1930s; altogether refers to 'Lewis' ringed-tail iguana'.
Distribution: Endemic and currently restricted to the east interior of Grand Cayman Island with extremely rare occurrences south of the Queen's Highway; fossil and bone records indicate it was more widespread extending into dry shrublands and coastal habitats; prefers shrubland with rocky outcrops and the margins of forests.
Description: Previously listed as a subspecies of Cyclura nubila as, Cyclura nubila lewisi, through genetic analysis it has recently been upgraded to a distinct species making a total of
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| 2. Detail of head |
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| 3. C. lewisi feeding |
Diet: Essentially a herbivore, consuming leaves, stems, bark, seeds flowers & fruits from a host of over 45 plants and plays an important role in the dispersal of seeds; on rare occasion supplement diet from consumption of invertebrates such as insects, insect larvae, slugs and crabs; have been observed consuming fungi, bird carrion, feces, skin sheds and small pebbles; only real natural predator is the native racer snake, Alsophis cantherigerus that preys on young; introduced cats, dogs & pigs that went feral on the island have taken a heavy toll on lizard populations by killing juveniles, sub-adults and adults; introduced rats also maim and kill young; adults have no natural or native predators.
Habits: This lizard is diurnal most active during bright daylight and seeks shelter and resting quarters in small limestone caves, rock crevices, hollowed out trees or tree limbs during darkness; vision is the most active sensory perception and relies on light for efficacy; chemoreception or chemical cuing is also important in communication with one another from pheromones released by the femoral openings; to thermoregulate body temperatures they do
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| 4. Refuge in a hollowed tree trunk |
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| 5. Female climbing |
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| 6. Juvenile |
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| 7. One regal animal |
Critically Endangered (3.1) IUCN |
| 1. Kuhli's parachute gecko ~ P. kuhli |
Kuhli's Parachute Gecko
Family: Gekkonidae
Genus: Ptychozoon
Species: Ptychozoon kuhli
Length: 70-95mm/2.75-3.74in (SVL); 14-19cm/6-8in total length (TL)
Weight: 7.5-15.45g/0.26-0.54oz
Longevity: 3-5yrs in wilds; up to 10yrs for captives
Name Origin: Ptychozoon kuhli ~ Pty is Greek for 'fold' in reference to cutaneous fold; cho is from the Greek word khos stipulating a word as plural it follows such as 'fold(s)'; kuhli honors the German naturalist, Heinrich Kuhl (1797-1821) who studied & classified the Dutch East Indies fauna; altogether refers to, 'Kuhl's cutanaeous folds lizard'.
Distribution: Is an Indochina species with a range from Myanmar (Burma), southern Thailand, Malay Peninsula, Sumatra, Java, Brunei, Sarawak, Sabah and various Indian Ocean Indonesian islands; prefers humid & warm primary & secondary tropical jungles.
Description: Body plan of this lizard is geared for cryptic camouflage; body & tail is highly flattened with skin flaps running longitudinally down lateral sides of body, neck, head & limbs; these cutaneous membranous folds have no muscular or bone support; tail is serrated and fringed; feet & foot digits are broadly dilated and strongly webbed with undivided transverse
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| 2. With flattened body & cryptic coloration P. kuhli is a master at camouflage |
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| 3. Note dorsal tubercles |
Diet: These insectivore lizards scamper to collect smaller invertebrates such as insects and arthropods; is beneficial to man in that it is a natural predator to mosquitoes; main predation on this lizard are smaller raptors that can navigate forest canopies; snakes and other larger lizard species.
Habits: Characteristics of the unique body structures first evolved as an aid in camouflaging the animal; P. kuhli is nocturnal and in resting during the day in the open instead of hiding in nooks & crannies, it relies heavily on camouflage in avoiding predator detection; toe pads and
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| 4. Ventrum morphology |
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| 5. Parascending |
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| 6. Female after laying her pair of eggs |
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| 1. Broad-headed skink ~ P. laticeps |
Broad-headed Skink
Family: Scincidae
Genus: Plestiodon (formerly of Eumeces)
Species: Plestiodon laticeps
Length: 14.3cm/5.6in SVL; 15-43cm/5.9-17in total length (TL)
Weight: 38gm/1.34oz
Longevity: Up to 10yrs
Name Origin: Plestiodon laticeps ~ Plesti is Old Church Slavonic meaning to 'plait', or may come from the Greek word plesso meaning 'to terrify'; odon derives from the Greek word, odontos meaning 'tooth'; latus is Latin for 'broad' and ceps is a Latin suffix for 'head'; altogether refers to 'plaited tooth (or terrible tooth) broad head lizard'.
Distribution: Formerly included in the genus, Eumeces; due to divergent dating, gene partitioning & mtDNA analysis, species representatives of East Asia & North America were pulled from the African Eumeces clade and listed under the new Plestiodon skink genus; plestiodons first diverged from Africa into E. Asia, then migrated to N. America ~18-30mya via the Bering Strait (Beringia); P. laticeps is the basal Plestiodon representative in N. America; today's distribution is endemic to the southeastern states from the E. Coast between extreme southeastern Pennsylvania & north central Florida westwards to Kansas & eastern Texas; prefers moist wooded areas or more open spaces with plenty of ground litter shelter provided by leafy debris and rubble piles.
Description: After Plestiodon obsoletus, the broad-headed is N. America's second largest skink; typical of most skinks scales are very smooth, overlapping and shiny; exhibits tail autonomy where tail will break off at fracture zone near tip; legs are short in supporting a
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| 2. Breeding male |
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| 3. Juvenile |
Diet: Is mostly carnivorous consuming mainly invertebrates like insects, spiders, snails, slugs and amphipods along with invertebrate larvae; smaller lizards may also be taken with rare cannibalism having been observed in eating their own young; on occasion fruit and flower blossoms are also eaten; observers have witnessed this lizard shaking the nests of paper wasps, to get at the larvae; apparently the swarming wasps' sting cannot penetrate the scales of this skink; predators abound in other reptiles, crows, owls, hawks and small carnivorous mammals such as raccoons and skunks.
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| 4. Male combat |
Habits: Is arboreal frequently among treetops and likes to perch on tree stumps and wooden fencing; adult males are very territorial, in particular during breeding season and will savagely fight when encountering one another; as mentioned, P. laticeps occurs in regional sympatry with other species in the Plestiodon genus such as P. fasciatus & P. inexpectatus; this territorial overlap with closely related species of similar phenotypes normally does not turn out too well under the competitive exclusion hypothesis due to over competition of prey resources; but due to P. laticeps larger size, larger prey is utilized where the other plestiodonans seek out the smaller, thereby available prey resources are partitioned out; also,
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| 5. Female tending eggs |
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| 6. Hatchlings & neonates |
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| 1. Allison's anole ~ A. allisoni |
Allison's Anole
Family: Polychrotidae/Iguanidae
Genus: Anolis
Species: Anolis allisoni
Length: ♂ ~ 10cm/3.9in SVL; ♀ ~ 7.5cm/3.0in SVL; 19.6-25.4cm/7.7-10in (TL)
Weight: ~ 4.5gm/0.16oz
Longevity: Average ~ 4yrs but can double that up to 8 yrs
Name Origin: Anolis allisoni ~ Anoli is Antillean native description; allisoni is in honor of Allison V. Armour by Thomas Barbour who first described the species in 1928; Armour was a naturalist who took Barbour to the West Indies on his research lab vessel the Utowana; altogether refers to 'Allison's anole'.
Distribution: Found native to Caribbean islands in particular central Cuba, Hispaniola & Bahamas and to Mesoamerica on Gulf of Mexico side on atolls and cayes off Belize coastline, Quintana Roo, Mexico and Central American nations on their eastern inland coastlines; is considered a trunk-crown anole preferring a diverse range from 1.5m/4.95ft off the ground on tree trunks & shrubs to as high as the tree canopies go in tropical to subtropical flora settings.
Description: Depending on what authority your reading or speaking to, anoles are currently being pushed as listed under family Polychrotidae; National Center for Biotechnology Information (NCBI) still list anoles under the family Iguanidae; there is still a strong genetic
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| 2. Note male dewlap |
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| 3. Brown color phase |
Diet: Is a generalist and opportunistic insectivore consuming invertebrates; will sit and wait to ambush, forage or actively pursue prey; small to medium various insects, spiders and moths make-up the primary diet; A. allisoni has a slew of predators that feed on it; birds such as egrets & trogons, jumping spiders, tarantulas, snakes, conspecific lizards, frogs, whip scorpions and scolopendomorph centipedes are a few animals that prey on this anole taking juveniles as well as adults.
Habits: Adaptive radiation, microhabitat ecology, natural selection, sympatric species association and ecomorph diversity have all played a role in shaping this anole and other anole species' way of life; is diurnal with excellent eyesight relying on vision for intercommunication, spotting & fleeing predation and detection of prey; eyes set on sides of head give a 180° view
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| 4. The bifoveal eye |
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| 5. Favored position |
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| 6. A pair mating |
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| 1. Veiled chameleon ~ C. calyptratus |
Veiled Chameleon
Family: Chamaeleonidae
Genus: Chamaeleo
Species: Chamaeleo calyptratus
Length: Ave: 35-45cm/14-18in total length (TL); ♂ ~ up to 60cm/24in TL; ♀ ~ up to 33cm/13in TL; tail length: 15.2-30.5cm/6-12in
Weight: 0.91-1.81kg-2-4lb
Longevity: Normally 5yrs for females, up to 8yrs for males in captivity; unknown in wilds
Name Origin: Chamaeleo calyptratus ~ Chamaeleo derived from Latin word, chamealeon which is rooted from Greek word, Khamaileon akin to chton referring to 'earth' as opposed to sky; calypt is from Greek word, kalyptein meaning 'concealed' referring to color changes; ratus is Latin meaning 'fixed' in reference to lizard's slow movements; altogether refers to 'concealed & fixed earthy lizard'.
Distribution: Is native to Middle East within Yemen extending beyond the border into southern Saudi Arabia; is found on mountain slopes along the Yemeni coastline, where rains form from condensed Red Sea vapor and may exceed 203.2cm/80in per year; also are found more inland in arid wadis where year round water and vegetation occurs, on high dry Yemeni plateaus & grasslands and along Saudi Arabia's southwestern coast in small forested river valleys; prefer a temperature range of 23.9-35° C/75-95° F, but unlike most chameleons, can tolerate wider temperature ranges; has been introduced in Florida & Hawaii where small wild populations have been established.
Description: Is literally described as one of the most colorful & grumpiest of chameleons; is very territorial with males exhibiting particular aggression towards one another; possess
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| 2. Note casque, feet & hyoid horn |
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| 3. Note eyes |
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| 4. C. calyptratus female |
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| 5. C. calyptratus male |
Diet: Although is primarily an insectivore consuming small invertebrates, is considered an omnivore, for it will supplant its diet with leaves, blossoms & fruit from various plants; one main contribution to a vegetable diet from a lizard that is equipped for snapping up insects with a projectile tongue, is that during arid and drought conditions, plants become a main water supply; year round diets consists mainly of insects; in being able to survive in more arid climates, locusts are a mainstay; C. calyptratus appears to be attracted to green insects; unlike most lizards that swallow food whole, chameleons chew food first before swallowing; natural predation comes from native birds of prey and snakes; local folklore developed from tribal ways persist and insist that throwing a veiled chameleon into a fire will bring good fortune.
Habits: Being an ambush predator, as mentioned under Description, they are capable of remaining motionless for hours on end; moving methodically and very slow they do not rely on speed to capture prey or flee threats; instead C. calyptratus relies on being unseen by blending into its background and standing still; if encountered will gape mouth and hiss; in walking as a rear foot is placed forward, the opposite fore foot is lifted advancing the animal
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| 6. Capturing a meal |
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| 7. Lft: hatchling; Middle: neonate; Rt: young juvenile |
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| 1. Mangrove monitor ~ V. indicus |
Mangrove Monitor
Family: Varanidae
Genus: Varanus
Species: Varanus indicus
Length: Size varies from various geographic locations ranging from .2-1.5m/.66-4.92ft TL
Weight: 0.5-1.9kg-1.10-4.19lbs
Longevity: Ave: 10-12yrs, but can just exceed 17yrs
Name Origin: Varanus indicus ~ Varanus is derived from Arabic word, waral which translates in English to 'monitor'; indicus is Latin for the country of 'India' although reference is to its native Indonesia, for it is not found in India; altogether refers to 'monitor lizard of Indonesia'.
Distribution: V. indicus is widely distributed most probably first arising from East Indies (Indonesia); currently is found in eastern sector of Indonesia, portions of Queensland & Northern Territory, Australia, New Guinea and its adjacent islands, Timor and numerous Pacific tropical islands such as Marshall, Marianas, Solomon, Aru & Kei Islands and the Bismarck Archipelago; introduced by man into Micronesia & Japan; always near a water source, prefers inhabiting mangrove stands, the rims of damp forests near coastal rivers and more inland around periphery of lakes and swamps.
Description: Across the huge expanse in range of hundreds of km/mi in distance between islands inhabited, physiology has changed greatly for this one species; for this reason, V.
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| 2. Note gold eye |
Diet: Is an opportunist carnivore consuming anything available; general diet is associated with what relevant environment offers; consists mainly of invertebrates (worms, snails, insects, crabs), frogs, fish, lizards, snakes, birds, juvenile crocodilians, carrion and reptile & bird eggs; on islands where it was introduced by man as an invasive species to control ant, beetle and rat populations; in domesticated urban settings attacks poultry, eggs, piglets and garbage; in
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| 3. V. indicus actively seeking prey |
Habits: This ubiquitous monitor lizard is unparalleled when it comes to survival behavior; although primarily a coastal marine animal, it is found at home in jungle perimeters, in the open, in coconut plantations, mangrove marshes and inland swamps; accepting a highly varied prey diet, it will chase, climb, dig underground, swim and dive or simply rest in ambush for prey items; they are comfortable resting or taking shelter in trees or water; jumping from the highest
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| 4. Scaling & resting in trees |
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| 5. Note hind & fore claws |
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| 1. Mountain boomer ~ C. collaris |
Mountain Boomer
Family: Crotaphyidae
Genus: Crotaphytus
Species: Crotaphytus collaris/
Length: 10-14.5cm/3.9-5.7in snout-to-vent (SVL); 20-30cm/12-14in total length (TL)
Weight: ~ 40gm/1.41oz
Longevity: Up to 10yrs
Name Origin: Crotaphytus collaris ~ Crotaphytus is derived from Greek word, krotaphos meaning 'head temple' in reference to presence of small polygonal scalar plates; collaris is Latin for 'collared' referring to dark neck bands; altogether refers to 'polygonal temple plated & collared lizard'.
Distribution: Are limited to south central United States and northern Mexico along the U.S. border; states it occurs in is from central Texas up to extreme southwest Illinois westwards to eastern Utah and down into Baja Califronia & Arizona going back eastwards through Mexican border to Texas; prefers arid scrublands and plains (up to 2,575m/8,500ft in Southwest) with rocky outcrops.
Description: Common name is more aptly collared lizard, due to the 2 black neck bands, but as a kid growing up in north west Texas, we called them mountain boomers; theory goes that the colloquial name, 'mountain boomer' arose from early settlers heading west for the California gold rush, heard winds blowing through canyons or as echoes through mountain valleys and mistakenly thought it was an animal making the noise; since this lizard was one of the most common animals encountered on their sojourns,
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| 2. Female, note brown coloration |
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| 3. Male scouting his turf |
Diet: Is a diurnal hunter and stalker; chases down or pounces on prey capturing it with its large mouth and muscular jaws; consumes larger insects such as grasshoppers, cicadas, beetles and will take spiders, smaller lizards & snakes; on occasion will supplement diet with leaves, blossoms and berries; is a true carnivore and cannot maintain a sustaining weight mass strictly from plant material; primary predators are hawks, larger lizards & snakes and smaller carnivorous/omnivorous mammals such as skunks, raccoons & fox if they can catch them.
Habits: Growing up in West Texas, C. collaris was my favorite lizard; not only for its color, but it was a true boyhood challenge in catching them and a honor when the feat was accomplished; this lizard will vigorously bite and may draw blood; it is a lively lizard darting to and fro when in chasing after prey, or fleeing from alarm; as kids we sometimes called it the 'cat lizard' for if observed as undisturbed long enough, at times when it saw prey, it would crouch and slightly wiggle its tail before pouncing, just like a cat; is always on or near rock outcroppings it utilizes for seeking shelter in crevices, to sit atop the highest rock to perch and survey its surroundings or to bask; preferred basking temperature range is rather high at 41-43° C/105-110° F; ideal temperature for all other activities is 27° C/80° F; males are solitary and very
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| 4. Female pals |
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| 5. Juvenile |
Snakes:
Snakes are nature's youngest reptile experiment, but the serpentine fossil record is poorly known. The complex but frail and fragile skeletal structure of snakes is ultimately destroyed long before being ideally fossilized. Therefore, the origin and evolution of snakes has been very difficult in piecing together and classifying.
Cotylosaurs are the oldest of known reptiles appearing ~315 mya as evolved labyrinthodonts. They were the first to oviposit on land cleidoic (shelled) eggs. A cotylosaur living 312 mya was from a genus known as Hylonomus. As mentioned in the 'Reptilian Discussion,' from the fossil record we do know that the lizard-like reptile Hylonomus was an indirect ancestor to lizards, giving rise to various clades of lizard-like reptilians that eventually evolved into primitive lizards proper occurring some 215 mya. Cotylosaurs began diversifying from the earliest anapsid skull structure into the other two skull structures of being synapsid and diapsid in nature. While the remaining anapsid cotylosaurs gave rise to turtles, the synapsid cotylosaurs gave rise to mammal-like reptiles that eventually formed the mammal group. The diapsid cotylosaurs diversified that eventually led to six groups of animals; one group extinct with the other five extant. The groups are the extinct dinosaurs, birds directly arising from theropod dinosaurs, tuataras, crocodilians, lizards and snakes deriving from lizards. Hylonomus had a diapsid skull, in which all its lineage of lizards and snakes arose from using the structuring for jaw muscle attachment. The actual holes of extant lizard skulls today show one hole as regressed, while both have fused altogether in snakes. Nonetheless, their skulls are diapsid in origin. From this we can ascertain that snakes are close relatives to lizards, but no less are distant evolutionary cousins to crocodilians and birds as well.
Out of the true lizard group arose the varanoid or monitor-like lizards in the late Jurassic some 180 mya. Varanoids were primarily semi-aquatic or fully aquatic lizards that gave rise to the largest lizard ever in the 17.5m/57ft mosasaur, Hainosaurus. True monitor lizards (varanids) from the family Varanidae, were primarily terrsetrial originating in northern Asia 90 mya.
Monitor lizards are set apart from other lizard clades in that varanids have a relatively high metabolic rate for reptiles, have developed sensory adaptations for hunting live prey (forked tongue, Jacobson's organ), have the unique ability to distend jaws due to a lowered hinged jaw enabling them to swallow large prey whole and recently scientists have discovered that varanids possess venom. Of the genus Varanus, species are morphologically conservative, but when it comes to body mass, species vary five orders in magnitude. This is comparable to comparing the body mass between an elephant and a mouse, which of course are both mammals but each entirely in a different genus.
From varanus is a varanoid sister group from the monophyletic family, Lanthanotidae known as the earless monitor. Lanthanotids today are rare consisting of a single extant species, Lanthanotus borneensis found only on the island of Borneo. Along with the typical physiology traits of monitors, in addition they lack an external ear, possess knobby scales, shed body skin wholly and have a lower transparent eyelid that could possibly be a precursor to the brille (transparent eye scale). They burrow and swim by means of serpentine motion. Lanthanotids are fossorial and semi-aquatic and it is most probable from this burrowing reptile group that the lizard transitioned into snakes during the mid to late Cretaceous.
There is current argument, that proposes snake origins as deriving from the lizard suborder, Iguania. But until credence is more detailed and specific, here, we're staying with the monitor transition.
As in all aspects to life through natural selection, snakes are a product of evolution. For snakes and also for a few other convergent animals such as caecilians and amphisbaenians, a tessellated evolution occurred in the skull versus the post-cranial skeletal osteology.
The snake skeleton is comprised basically of a skull, vertebrate column and ribs. Their are no neck vertebrae, only the body's thoracic, abdominal and caudal region are covered in backbone The skull portion housing the braincase is fully ossified with numerous snout and jaw regions jointed such as the distension of the quadrate and maxillary to allow the swallowing of large prey. The skeletal body portion has evidenced pachyostosis, where solid bone structure has formed with little or no marrow.
Evolving from burrowing varanoids, through gene expression the reptiles began losing their limbs with forelimbs going first before the hind limbs. It is not a matter of more new genes but in the rearrangement of existing gene construction. Limb building in the fetal stage was decommissioned. Limb loss was an adaptation to living a fossorial existence causing limb development to slow, stop early then be reabsorbed altogether.
At times in animal embryological growth, dormant gene expression may reawaken and express a primitive trait. This is why at times a dolphin may exhibit a limb instead of a fin or a human have an extended tail beyond the body, but as far as snake limbs go, there will never be another forelimbed snake, for the blueprint was lost due to HOX genes. In vertebrates, forelimb development occurs to the most anterior domain of Hoxc-6 gene expression, but only with Hoxc-8 present. In combination with Hoxc-6 and Hoxc-8, gene expression determines thoracic vertebrae. With snakes, Hoxc-8 in the earliest of embryological development has been permanently taken out in expression, so Hoxc-6 does not express in the absence of Hoxc-8. Therefore the earlier forelimb development does not occur. When Hoxc-8 does later appear, longer thoracic vertebrae development instead occurs. There is no neck because with no forelimbs, there is no neck vertebrae gene domain.
The first of the primitive snakes began displaying pachyostosis and limb degeneration in fossil finds. True snakes began to appear in the Cretaceous some 130 mya. Fossilized snake vertebrae of Lapparentophis defrenni was found in the Saharan desert dating back to this time. Unfortunately, most of the oldest fossils are composed of only a few vertebrae, but we do know for a fact that the first snakes were at least hind limbed due to later finds of more complete serpentine fossilization.
Early snakes were unquestionably hind-limbed, or to dare say bipedal, such as Pachyrhacis problematicus (which was at least semi-aquatic if not fully), Haassiophis terrasanctus (also aquatic) and Eupodophis descouensi which fossil remains were also found in shallow marine
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| 1. P. problematicus re-creation |
These hind-limbed snakes occurred 92-99 mya during the Cenomanian stage of the Late Cretaceous. Until more preserved earlier fossils of primitive snake anatomy are discovered, one cannot exclude that limbs were lost, then might have been regenerated, then lost again
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| 2. H. terrasanctus |
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| 3. H. terrasanctus limb |
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| 4. E. descouensi |
By 70 mya, snakes were possessing very reduced or only rudiments of hind limbs. One of these serpents was Sanajeh indicus found in 67 million year old Indian gravelly limestone outcroppings. The fossil is an exceptionally euphoric discovery as the snake was in a sauropod nest composed of titanosaur eggs and hatchlings. A landslide immediately covered the nest site and snake freezing that exact moment in time. The 3.48m/11.5ft snake was coiled around a broken egg and a hatchling beside two other eggs.
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| 5. Re-created S. indicus in titanosaur nest |
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| 6. Near perfectly preserved b. idelmani |
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| 7. Note spurs (remnant thigh bones) |
The extinct genus, Boavus abounded wherever there was warm year round tropical settings and boids today still maintain that requisite. True boids began appearing around 50 mya, but still retained a vestigial pelvic girdle with a thigh bone known as a spur protruding (male spurs extend more than females) on each side of the cloacal opening. Just as currently living pythons and boas, they retained the primitive characteristics of a somewhat rigid lower jawbone with coronoid elements and a bigger left lung nearing 75% of the size of the right lung, where the left lung is almost defunct in all other more modern snake families.
Boids were dominant until around 36 mya when another group of successful snakes, known as colubrids began spreading out. They were different from the boids in that they had developed a wider mouth gape to feed on larger prey. These early colubrids all possessed aglyph maxillary dentition as boids, but in addition, in losing the lower jaw coronoid bones, both jaws now were flexible able to dehinge at joints. Initially, colubrids were out-competed by boids and remained small as a group until around 20 mya. This is about the time continental drifting reached current positions. As tectonic plates took continents away from the equator, climates cooled on once equatorial lands, boids were unable to cope. From many regions they were once common, boids began to disappear and were greatly reduced in number where they were still surviving. From this episode, colubrids quickly filled in the voided niches and in evolving through hibernation, surpassed boids as the dominant snake group.
Around 15 mya a family of colubrids began appearing with greatly enlarged rear teeth that became fanged as a venomous delivery system. This group of rear-fanged colubrids are called opisthoglyph. For snakes, a tooth is technically a fang if it acts as a delivery system for venom. Boid species possess some of the longest teeth in the snake world and although they appear fang-like, they are not because there is no venom involved. The venom from these early rear-fanged snakes was highly modified saliva enriched with proteins that destruct instead of sending information to construct cellular maintenance. The proteins are composed of phospholipases, phosphodiesterases and proteases, which gives inference to a pancreatic source as these proteins are enzymatic for digestive purposes. Duvernoy's gland is the reservoir for the venomous secretions. The fluid filled gland's original sole function was as an aid to swallowing by secreting the fluid into the mouth and down the throat.
Ridges and grooves may be present on all aglyph dentition. For opisthoglyph dentition, grooves became dominant on posterior or medial enlarged maxillary teeth. Two or more maxillary teeth can form too close in proximity and in between a groove is formed. Opisthoglyph snakes must first gain a strong hold with the rear fangs on whatever they have bitten to allow the venomous secretions that are traveling down the groove to enter the wound. As a condensed drop on the outside of a glass filled with iced water slides down the glass, surface tension allows venom to trickle down the groove. Once the venom flows down the groove it enters the victim's tissue much like a sponge soaking up water as the open wound tissue behaves as an attractant. This new venom system was a novel food capture giving the snake a great advantage in subduing prey without risking physical harm from the struggling victim. A secondary advantage was its usage as an effective defense mechanism against predators.
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| 8. Opistoglyphous |
Later, around 13-12 million years ago, proteroglyph dentition appeared from opistoglyph fangs migrating forward in the mouth. Proteroglyph fangs were still fixed, but were hollow from grooved fangs filling over and around the grooved channel. With the tip of the fang remaining opened, this fang arrangement is much like an hypodermic needle. In addition to a newer fang and delivery system that could inject more advanced neurotoxic venom in one strike, these snakes gained respect from most other animals, including primates. Humans still carry an early innate primate fear of snakes; in particular the venomous ones. The mandible became set back with a shorter but stronger quadrate bone. Thus arose the family of elapids and from the family Elapidae branched off the subfamily, Hydrophiinae, sea snakes that are viewed by most as holding the most concentrated and toxic venom.
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| 9.Solenoglyphous |
By 10 mya, dentition modified further in some species ushering in a new fold of snake known as viperids. Preliminary molecular evidence indicates vipers did not come from proteroglyphs, but directly from boid stock. This new venom delivery system is known as soleonglyph and can be folded inwards (recoiled) when at rest and sprung into immediate erection to deliver a deep strike into tissue where it can immediately activate. Solenoglyphs use a rotating maxillary bone to recoil or erect the fangs.
From viperines (vipers lacking pit organs) the newest snake kid on the block evolved that we call pitvipers, due to a pair of facial pits that sense infrared radiation and also thermoregulate. Viperines utilize thermal cues for striking, but do not thermoregulate. The pits also aid in sensing and sizing predators. A member of pitvipers is the famed crotalines best known as rattlesnakes. Due to the heat sensing pair of pits, a blind rattlesnake not only would know the size and location of an intended prey, it would know right where to strike the most vulnerable part of the prey's body. Facial pit heat sensing has had parallel and direct evolvement, as boids possess the facial pits.
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| 10. A. Aglyph B. Opisthoglyph C. Proteroglyph D. Solenoglyph |
And the Lord God said unto the serpent, Because thou hast done this, thou art cursed above all cattle, and above every beast of the field; upon thy belly thou shalt go; and dust shalt thou eat all the days of thy life. Genesis 3:14
This biblical verse was perhaps meant to be metaphorical or to play on natural fears, for to be taken literally, it is errant reading. The long transverse ventral scales are very efficient in propelling snakes through any terrain from heavy vegetation to sands and rocky outcrops. But of course, snakes not only crawl on grounds, they are also arboreal, aquatic, aerial (as one genus glides through the air) and as we have just read, once possessed legs. Dirt, they do not eat...they are strictly carnivorous. As not seemingly cursed, they are very accomplished as a species.
Snakes are essentially quasi cylindrical with a body plan for swallowing large prey whole. Many of the skull bones are loosely attached, in particular the jaw bones which may separate away from each other independently and unhinge from their joints. For more room in swallowing prey, the left lung has become vestigial or absent altogether with the right lung extending generally, to half the length of the body. There is no diaphragm and due to this the heart is able to move around encased in a sac called the preicardium. Paired organs, such as kidneys, stagger one another to make room for whole food.
The nostrils lead into the mouth cavity just behind the upper maxillary teeth. When ingesting a large meal air passage may be blocked, but snakes counter apnea for very long periods in being poikilothermic, therefore demanding only a low oxygen supply. In addition, the anterior portion of the right lung can extend into the throat during airway compression, while the posterior end acts as an air reservoir.
The digestive system of snakes, among the most complex in the animal kingdom allows the snake to swallow whole prey as much as 50% and even up to 160% in some cases more than their own body weight. The ingested feeding stimulates the rapid growth of the intestinal lining allowing the weight of the small intestine to double in weight to accommodate the meal. On the other hand, when a snake has extended fasts for various reasons, the mucosa lining of the small intestine atrophies conserving energy.
The digestive enzymes are very efficient in extracting and assimilating nutrients and in some cases completely digests bones. Adapted to intermittent feeding behavior, the snake rests during digestion of a big meal, but when threatened just after consumption, can readily regurgitate the undigested contents to be more alert and agile.
The skin is entirely covered in scales which may be smooth or keeled while in addition, keeled scales may possess a pair of pits. Ventrum scales, except in a few cases such as aquatic Acrchordus species, are always elongated and smooth utilized for gripping surfaces and developing friction for mobility. Caudal scales beyond the cloaca are either single or doubled. Since snakes have no eyelid, each eye is covered with a transparent ocular scale called a brille.
Snake skin is keratinized and impermeable, therefore unlike cutaneous amphibian respiration, snakes are only pulmonary in their breathing.
Shedding of skin or ecdysis is performed up to four times within their first year of life due to rapid growth. From then on, shedding occurs once or twice a year. Shedding allows for growth and gets rid of worn out skin and ectoparasites. Ecdysis is normally done wholly as opposed to in parts and transpires when connective tissue between the outer old skin and inner new liquefies.
There are several methods of snake mobility. The most common is serpentine lateral undulation where sinusoidal movement is performed on land and in swimming. A second and third form of mobility by arboreal snakes is concertina and branching locomotion. Lateral undulation or sidewinding is employed by xenophidian snakes to move across loose or slippery substrates. Concertina is where a snake in succession will vertically crawl up a trunk with a convoluted body acting as a brace against the bark then extending its anterior end forwards. The anterior end then anchors allowing the posterior end to move forward. Branching involves grabbing a branch with the posterior end as a set anchor to thrust the anterior end forward to another branch. This is also a repetitive procedure. Rectinlear or horizontal locomotion, where there is no lateral body motion, is performed in a straight line. In this movement, a series of skin ripples, caused by the lifting and moving forward of ventral scales, propels the snake forward. This is slow motion and is usually a method chosen to not alarm potential prey with sudden or quick movement. The last form is gliding as displayed by Chysopelea and Philodryas species. These snakes, by extending the vertebrae and flattening the body, creates a concave winging giving lift due to a ventral increase in air pressure.
All snakes utilize internal fertilization with most being oviparous, although ovoviviparity is not uncommon where the eggs are retained and hatched inside the mother, then born live. The common anaconda, Eunectes murinus and Boa constrictor are viviparous in having a placenta and give live birth just as mammals do.
Size ranges from the extinct Titanoboa cerrejonensis, which was 12-15m/39-49ft, and the extant Python reticulatus measuring up to 9m/30ft. The heaviest extant snake is Eunectes murinus weighing up to 97.5kg/ 215lbs growing to 7.5m/25ft long. On the other hand the smallest snake is Leptotyphlops carlae with a length expanding no more than 10cm/4in. On average snakes range around 1m/3.3ft.
Biotopes are varied ranging from the equator to the Arctic, from desert to rainforests and from sea level and sea to 4,850m/16,000ft in Tibet.
Current snake species number anywhere from 2,600-3,000. All snakes are grouped under the order, Squamata and further under the suborder, Serpentes that is being pushed aside in favor of naming the suborder as Ophidia. Colubridae is still the predominant family, but due to monophyletic studies of mitochondrial DNA and differing morphological characteristics, colubrid members are being whittled down with species gaining their own respective new families.
For further reading on snake descriptions, if you like you may go to my other website theponderinggulch.com and look to the side as you scroll for the science articles. Once science articles are found, click on 'Frontyard Sense/Backyard Science II,' then when on the article, scroll down until you reach the snake chapter.
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| 1. Texas blind snake ~ L. dulcis |
Texas Blind Snake
Family: Leptotyphlopidae
Genus: Leptotyphlops
Species: Leptotyphlops dulcis
Length: 17.8-27.9cm/7-11in total length (TL)
Weight: 1.2-2.0g/.04-.07oz
Longevity: No data
Name Origin: Leptotyphlops dulcis ~ Leptos is Greek for 'thin'; typhlos is Greek for 'blind', while ops is also Greek for 'eyes'; dulcis is Latin for 'pleasant'; altogether refers to 'slender blind-eyed charming snake'.
Distribution: Is found in the Southwest of U.S. from south central Kansas down through Oklahoma and into Texas westwards through south New Mexico into southeast Arizona ending through northern Mexico bordering Texas, New Mexico & Arizona; habitat is where there is moisture and sandy or loamy soils in semiarid deserts, grass prairies and mountain slopes; inhabits terrain from sea level to 1,500m/5,000ft.
Description: Is vermiform (worm-like) in appearance with dorsum & ventrum uniform sized glossy scales surrounding body, ventrum has no elongate scales for gripping surfaces; tail is extremely short ending in a scaled spike; vestigial eyes are buried underneath a translucent brille; to keep dirt out of mouth while burrowing, lower jaw is countersunk in contrast to upper;
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| 2. Note vestigial eye |
Diet: Most writings suggest these snakes exclusively dine on termites and ants along with the pupae of these insects; while it is true that both adult and larvae ants and termites make up the bulk of L. dulcis' diet, they will readily consume other insects and spiders when the opportunity arises; snakes eat whole prey as do blind snakes, but only most of the time; L. dulcis will not eat the heads of termites or will only chew out the juices of certain insects; predators abound in ophiophagous snakes such as the rear-fanged night snake, Hypsiglean torquata, smaller raptors such as the elf owl, Micrathene whitneyi and rodents.
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| 3. Consuming ant pupae - note mouth underbite |
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| 4. Living within rock crevices |
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| 5. A. Raking in prey; B,C&D. Skull Morphology |
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| 1. Plainbelly ~ N. erythrogaster |
Plainbelly Water Snake
Family: Colubridae
Genus: Nerodia
Species: Nerodia Erythrogaster
Length: ♂ ~ 76cm/29.9in SVL; ♀ ~ 122cm/48in SVL; Record: ♀ ~ 157.5cm/62in
Weight: Mean Ave: ♂ ~ 286g/0.63lbs; ♀ ~ 516g/1.14lbs
Longevity: 14.5-15 yrs
Name Origin: Nerodia erythrogaster ~ Nerodia is in honor of the Greek sea nymph, 'Nereis'; erythrogaster is derived from the Greek words, erythros for 'red' and gaster meaning 'belly' or is a combination of the 2 Greek words neros for 'flowing' and dia meaning 'through'; altogether refers to, 'Nereis' red belly water snake'.
Distribution: With subspecies is widely distributed ranging from southern Michigan, southeast Iowa & Delaware through sections of Illinois, Indiana, Kansas, Missouri, Kentucky, Virginia, all the southeastern states, Oklahoma, from central to eastern Texas and down into Mexico in the states of Nuevo Leon, Coahuila, Zacatecas & Durango; within this range is absent in the Appalachians and the Florida peninsula; species of Erythrogaster frequent permanent or semi-permanent bodies of slow water and is ubiquitous in aquatic habitat choice ranging from wetlands, rivers, creeks, streams, floodplains and seasonally flooded bottomlands, wet meadowlands, lakes, ponds and man made tanks.
Description: All dorsal scales are rough and heavily keeled; anal plate divided; eye pupils are rounded; due to strong and protruding muscle jaws, the neck is seen as distinct from head; sexual dimorphism is exhibited only in size with females being larger; the genus, Erythrogaster lumps all water snakes together essentially with uniform venter scale coloration, hence the common name of the group as plainbelly; this group of water snakes is
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| 2. N. e. transversa Note distinct neck |
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| 3. N. e. erythrogaster red ventrum |
Diet: Feeds exclusively on ectotherms, primarily frogs, toads and tadpoles, but other amphibians such as sirens are also consumed; will consume fish if they are in stranded pools, but do not go after fish in open waters as other water snake genera do; crawdads are also taken; will pursue prey if escape is attempted; juveniles feast primarily on invertebrates such as aquatic insects, tadpoles and small fish; predators abound in small carnivorous mammals such as raccoons and opossums, turtles, other snakes such as Agkistrodon piscivorous (water moccasin) & Lampropeltis getula (king snake) and crocodilians where present; shore and wading birds, Buteo jamaicensis (red-tailed hawk) & Buteo lineatus (red-shouldered hawk) and numerous larger fish will also prey on this snake.
Habits: As a youth, my favorite snake to catch was N. e. transversa in creeks and stock tanks; I don't know why, as it can be very foul tempered when cornered; it prefers first to flatten its body and hide cryptically or to slither off into tall grass near the banks or in fields instead of retreating into water; if cornered though, it becomes ill tempered repeatedly attempting to bite; it is without doubt the snake I have been most biten by; once held, as it wiggles and writhes, it will defecate exuding a foul smell; I also had them regurgitate their recent meal on me as well; one meal was a ranid bullfrog tadpole that was in the last stages of metamorphosing; with its similar coloration, triangular shaped head due to the jaw muscle protuberance, keeled scales and nasty disposition, many mistake it for the cottonmouth (Agkistrodon piscivorous) and unfortunately kill it; it can be readily identified by the round pupils and divided anal scale as opposed to the cottonmouth's elliptical pupils and single anal scale, but who wants to observe
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| 4. N. e transversa grouping to bask |
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| 5. N. e. neglecta cryptic neonate |
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| 1. Calabar python ~ C. reinhardtii |
Calabar Python
Family: Boidae
Genus: Charina (Calabaria)
Species: Charina reinhardtii
Length: .80-1m/2.6-3.3ft
Weight: 195-240g/6.88-8.4oz
Longevity: ~ 20-30 yrs in wild
Name Origin: Charina reinhardtii ~ Charina is derived from the Greek word, charicis (charis) for 'graceful'; reinhardtii honors Danish herpetologist, Johannes T. Reinhardt (1816-1882); altogether refers to, 'Reinhardt's graceful snake'.
Distribution: Endemic to western and central Africa widespread in tropical regions of Sierra Leonne, Liberia, Ivory Coast, Ghana, Togo, Benin, Nigeria, Cameroon, CAR, DRC (Formerly: Zaire), Congo (Brazzaville), Gabon & Equatorial Guiena including Bioko Island; prefers rain forest, swamp forest and overgrown banana plantation habitats.
Description: This snake has been a nightmare for taxonomic classification; is listed under the boid subfamily Erycinae, but classifying it as a erycine boa is conjectural; physically and morphologically it appears more as a blind snake or even an amphisbaenian on steroids; just in 1993 it was removed from the Eryx genus and added to Charina by Kluge based on phylogenetic analysis; currently, there is a strong push in removing it from Charina leaving that genus to the N. American boas, Charina bottae & Charina umbratica (rubber boas) and Charina trivirgata (rosy boa), while putting it under the monophylic genus, Calabaria; the body is shaped much like all fossorial animals in being cylindrical, possessing weak eyes and a likeness of appearance in a blunt head and blunt tail, unlike boas; Unlike all other boids, no palatal teeth are present and the compacted skull, modified for a fossorial digging lifestyle has a prefrontal bone; head is covered in large scalar shields and there are no thermoreceptive
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| 2. Note white markings on tail |
Diet: Almost wholly consists of rodent and shrew nestlings, in particular while still in early fur-less stages; in turn rodents make-up one of the major predators for juvenile C. reinhardtii mortalities; a detailed dietary analysis did reveal in an individual rat's regurgitation of charina snake egg contents; erycines appeared and diversified around the same geological period as rodents did suggesting the interdependence bound between these 2 groups; other predation apparently is not well documented, but the stress placed on a C. reinhardtii, once picked up from above and hand held, suggests that raptors may be a major predator.
Habits: Is a very shy, non aggressive and elusive snake; when confronted or even held never attempts to bite; defensive behavior is to coil tightly into a knotted rope-like ball; in the ball configuration head may be shielded in center or the tail; will undulate the tail appearing likely as the head of a snake about to strike; upon continual handling, captives will discontinue ball
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| 3. Lft: Head in center; Rt: Head outside center |
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| 4. Climbing ability |
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| 5. Lft: Female incubation; Middle: Hatching; Rt: Hatchling |
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| 1. Tar pot python ~ A. melanocephalus |
Tar Pot Python
Family: Boidae (Pythonidae)
Genus: Aspidites
Species: Aspidites melanocephalus/
Length: Ave total length (TL): 1.5m/4.93ft; Max TL: 3m/10ft
Weight: ~16kg/35.27lb
Longevity: 15-20yrs in wilds; 20-30yrs in captivity
Name Origin: Aspidites melanocephalus ~ Aspidites is Greek meaning 'shield bearer' in reference to large dorsal head scales; melan is Greek root word for 'black', while cephalus is Latin derived from the Greek word, kephalos meaining 'head'; altogether refers to, 'snake with shield bearing black head'.
Distribution: Endemic to Australia as broadly distributed from east to west in northern third of country; range includes majority of Northern Territory, Queensland's northern latitudes and Western Australia's northern third; the Pilbara population is isolated in the western range and may be disjunct from gene pool of rest; habits a wide range of habitats from wooded savannas & open forests to the arid northern coast, rocky outcrops, grasslands and along dry water courses.
Description: Most pronounced feature is the black head & neck as its scientific name refers to; dorsal portion of head is covered with large symmetrical scales; Unlike most other pythons, there are no heat receptor pits located in labials (lip scales); due to this it was thought A. melanocephalus was either a very primitive python or due to a more fossorial evolvement, lost the labial pits; as it turns out in recent analysis, the tar pot indeed does have a heat sensor pit
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| 2. Note large head scales |
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| 3. Ventral view of rostral pit |
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| 4. Color morphing from east to west |
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| 5. Devouring a lizard |
Habits: This nocturnal snake burrows preferring sand banks of dried out streams, termite mounds, hollow logs or large crevices in rocks or deep soils where it rests during daytime heat; males in seeking females are active a lot of the time during the day; tar pots have a high metabolism and during colder months have a peculiar way of basking by only protruding the black head from the burrow to absorb heat; they may also bask in the open by raising the head from the coiled body; to cool off, a habit is to bury their head; native aboriginals depicted this snake as part of their 'Dreamers' rituals in spirituality beliefs; tar pots for defensive measures rarely bite when cornered, but hiss loudly and strike normally with the mouth closed; when they do bite, it can make a severe wound from their large recurved teeth; main defense is to move off from the disturbance; as all pythons, tar pots constrict their prey to death prior to ingestion; due to lack of natural predators, most A. melanocephalus die due to a combination of starvation and/or internal parasites; mating takes place predominantly in late winter or early spring (July-September); males participate in combat fighting over females and may bite each other; in breeding, the male performs 'tactile stimulation' in crawling over female pressing his tail under hers while raking his larger spurs over one of her sides to stimulate her and align their cloacas together, where he can then insert a hemipenis into her cloacal opening; mating may last from 20 minutes to 6 hours and can be more than once for the pair; multiple partner matings have not been observed; females are oviparous; once a suitable site is picked will lay her egg clutch after a gestation period of 2 months; mean clutch size is 8, with clutch sizes ranging from 5-10; female will quit feeding to incubate her eggs becoming aggressive during this period; typical python 'shivering thermogenesis' is performed through muscular contractions stimulating production of metabolic heat; eggs hatch in 2-3 months from oviposition with hatchlings measuring 50-70cm/19.69-27.56in; once hatched, fend for themselves and begin feeding 2 days afterwards; although the IUCN has not had an official evaluation of population trends, this snake is not listed as threatened.
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| 1. Amazon tree boa ~ C. hortulanus |
Amazon Tree Boa
Family: Boidae
Genus: Corralus
Species: Corralus hortulanus
Length: 1.5-2.0m/5.0-6.5ft
Weight: 400-600g/14.11-1lb 5.16oz
Longevity: Wilds ~ 12-15 yrs.
Name Origin: Corralus hortulanus ~ Originally rooted from Greek word, korallium, corralus is from the Latin word, corallium meaning coral in reference to snakes multicolored patterns; hortulanus is derived from Latin word, hortus in reference to head color pattern resembling a flower garden; altogether describes, 'variety colored flower garden snake'.
Distribution: Natural distribution is endemic to South America; found within a broad range in Bolivia, Amazonian Brazil, southern Colombia east of Andes, Ecuador, French Guiana, Guyana, Peru, Suriname, Trinidad & Tobago and Venezuela; typically found no higher than 300m/990ft, this snake is basically arboreal in neotropical jungle settings.
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| 2. Uncommon melanistic phase |
Description: Due to arboreal way of life, is much thinner and smaller than other more terrestrial boids; tail is highly prehensile; bodies are laterally compressed with slender necks attached to much wider massive heads; teeth are long and recurved for grasping and holding onto prey while moving it to the back of the throat for swallowing; eyes are vertically elliptical; possesses heat sensor pits located between supralabial & infralabial scales; sense of smell in Jacobson's organ is highly developed, where tongue picks ambient environment molecules to be analyzed by the organ; this snake exhibits the whole hue of the color spectrum from blacks, grays and browns to shades of blue, red, yellow & orange; may be
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| 3. Gray garden phase |
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| 4. Blue garden phase |
Diet: In the wilds natural food prey items are birds (such as Chloroceryle inda, Coereba & Elaenia), bats (such as Phyllostomus bicolor, Rhynchonycteris naso & Myotis), lizards (such as Anolis, Basilicus & Iguana), microhylid frogs such as Elachistocleis, rodents (such as Akodon, Mus & Rattus) and marsupials such as Marmosa; juvenile diets also consist almost wholly of small vertebrates as well taking tree frogs, small lizards, birds & bats; neonates may take large insects and tree frogs; being one of the larger predators within tropical canopies, motionless stances, cryptic coloration and with a
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| 5. Garden phase |
Habits: C. hortulanus is solitary, arboreal and primarily nocturnal most of its life; at times though, may be observed as active during daylight and on the ground; most of life is spent in tree canopies hanging motionless in sit and wait ambush strategy, where prehensile tail is anchored around a limb or twigs giving leverage for a possible two-thirds body thrust to strike and capture prey or bite an adversary; this can
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| 6. Defense & ambush positioning |
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| 7. 3 red phases Lft: stonewash, Mid: garden, Rt: calico |
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| 8. Lft: orange phase, Mid: yellow phase, Rt: paradox phase |
basking after eating a heavy meal or when females are gravid; in mating, increments in temperature differences between night & day and overall slight temperature decreases starting in November trigger sexual responses; shorter daylight hours also initiate courting during winter months; courtship consists of a behavior by the male known as 'tail writhing' which initiates ovulation in the female if she is responsive; males frequently shed just before courtship as it increases his chances to mate; females are more responsive to freshly shed males; C. hortulanus will mate multiple times during the breeding period and a female may be bred by other males; males also use their spurs to stimulate females cloacal region; full ovulation in female occurs several weeks after copulation where the stored sperm then fertilizes her eggs; gestation period is 175-225 days; females are ovoviviparous giving birth to a litter of up to 12 live young; neonates are on their own from time of birth; first shedding occurs 8-14 days after birth; juveniles have a habit of knotting their tails due to not yet mastering the very prehensile tail; on rare occasion this can cause a necrotic effect with the tail rotting then falling off; both sexes are sexually mature at 3 years of age; though habitat is being destroyed, with its wide range in distribution this snake is not considered endangered yet.
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| 1. Arafura file snake ~ A. arufurae |
Arafura File Snake
Family: Acrochordidae
Genus: Acrochordus
Species: Acrochordus arafurae
Length: ♂ ~ 1.2m/3.96ft; ♀ ~ 1.5m/4.95ft
Weight: ♂ ~ 700g/1.54lbs; ♀ ~ 1.5kg/3.4lbs
Longevity: Ave: ~ 9yrs; up to 19-20yrs
Name Origin: Acrochordus arafurae ~ Acrochordus is from the Greek word, acrochordon meaning 'wart'; arafurae is in reference to the Arafura Sea; altogether refers to, 'Wart snake of the Arafura Sea'.
Distribution: Found in coastal regions and adjacent waterways of the Northern Territory & western portion of North Queensland in Australia, while also in southern New Guinea; prefers shallower rivers, streams & billabongs (Aussie description for small lakes) or any permanent bodies of water with fish; has also been observed in estuaries and swimming in the sea on occassion; this almost exclusive aquatic snake prefers freshwater and only on rare occasion travels via land to go to more viable water sources.
Distribution: Found in coastal regions and adjacent waterways of the Northern Territory & western portion of North Queensland in Australia, while also in southern New Guinea; prefers shallower rivers, streams & billabongs (Aussie description for small lakes) or any permanent bodies of water with fish; has also been observed in estuaries and swimming in the sea on occassion; this almost exclusive aquatic snake prefers freshwater and only on rare occasion travels via land to go to more viable water sources.
Description: The Arafura file snake belongs to the genus, Acrochordus which has 3 species; all 3 are only distantly related to the rest of all other extant snakes; closer family relations are extinct such as Anomalopheidae, Nigerophiidae & Paleopheiadae that died out during the Paleogene (Tertiary) period 35 mya; they were intermediate between primitve & advanced snake groups; A. arafurae is a large to heavy bodied snake with adaptations geared for a fully aquatic lifestyle; skin is loose & baggy covered with highly keeled non-lapping scales; scales are small, rugose & granular giving a warty appearance; sensor bristles appear on small outgrowths interstitially from skin; lacks the typical enlarged transverse scales typically found on terrestrial snakes; compared to body, head is small with small eyes placed dorsally on top
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| 2. Close-up; note dorsal eye, scales & bristles |
of head; teeth are solid and snake is nonvenomous; nasal plugs or valves are present for submergence; skull is modified to swallow larger prey with elongate quadrates and a quadrate-columellar articulation; there is no mid-ventral fold; tail is prehensile; this snake is not only sexually dimorphic in morphology with female being larger along with larger head, it is dimorphic in behavior in occupying different aquatic niches; females prefer deeper waters where male remains in more shallow; males also have longer tapering tail to accommodate the storage & housing of hemipenes; coloration may vary, but generally dorsum is a dark gray to light brown with reticulations of dark brown or black; reticulations are vertebral extensions to ventral surface; ventrum is normally whitish; coloration is more distinct & patterned in juveniles that dulls over time; there are no recognized subspecies.
Diet: Essentially is piscivorous feeding almost exclusively on fish relishing the eel-tailed catfish (Tandanus tandanus); are a few reports that it will also accept eels and carrion, in particular dead fish; as unusual for snakes, possesses a convoluted intestine much like quadrapeds; digestion is very efficient in even digesting, assimilating and utilizing scales & bone; contends with many predators including fork-tailed catfish (Ariidae), saltwater crocodiles (Crocodylus porosus), whistling kites (Haliastur sphenurus), black-necked storks (Xenorynchus asiaticus) and most significantly white breasted sea eagles (Haliacetus luecogaster); aboriginal people also consume this snake by flushing then capturing them in the water and throwing them onto land where they do not move well.
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| 3. Rare photo in capturing a catfish |
Habits: this is a very passive snake and usually never bites even when provoked or injured; mainly nocturnal foraging at night; female in deeper water will use prehensile tail to hold fast to aquatic plants waiting for fish to swim by; male is more active in shallower water in swimming searching for prey; both sexes will also crawl along the bottom and may travel up to 68m/224.4ft in the dry season and up to 166m in the wet season crawling or swimming; loose skin aids in swimming acting as a finned foil; another oddity for snakes is it will not capture prey until it is touched; bristle sensors aid in sensing prey; when prey is detected, the snake immediately coils around victim with granular scales aiding in firmly gripping slippery prey in water; coiling is not for constriction as in boids, but more so in securing prey to maneuver mouth into place of prey's head where the snake places a firm bite hold; in this coiled and head bite position the snake then if in deep enough water, will hold the prey vertically upright to create an hypoxic condition for the fish victim; once prey is stilled and totally subdued, the snake begins to consume the meal head first; females may eat a fish up to 1kg/2.21lbs; males eat smaller sized fish; in dry season, A. arafurae concentrates in density into backwaters & the billabongs; upon arrival of wet season they then move back to streams, flooded grassland and mangroves; after a few gulps of surface air, can remain submerged for hours at a time; this snake has most extensive vascular respiratory system of any known snake; right lung stretches just to cloaca and is vascularly parenchymal (having functional parts) throughout length; also possesses supplemental cutaneous respiration abilities; has a very slow metabolic rate and can survive eating only 3-5 times a year; another snake oddity of this snake is thermal acclimation; unlike ectothermic snakes, A. arafurae is homeothermic and can maintain average body temperatures between 26-30 degrees Centigrade
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| 4. Female resting on the bank |
or 78.8-86 degrees Fahrenheit; in being a low energy specialist, A. arafurae exhibits a very low rate of reproduction normally reproducing only once in a 8-10yr period; like mammal females possess a placenta, so are viviparous giving birth to live young; males' inverted paired hemipenis is fitted within tail and can store sperm for years; hemipenes are everted for intromission; mating occurs during the dry season and female will carry fetuses until the mid to ending of wet season, when she gives birth to anywhere from 6-30 neonates; Dubach et al. (1997) reported a captive female giving birth that had not been around a male for 7 years; this suggests that female A. arafurae are parthenogenetic or have capability of storing sperm for years; equal numbers of females & males usually occur during birth; neonates average 36.6cm/14.41in in SVL length and 26g/0.92oz in mass; due to predation there is a high mortality rate in juveniles; females show substantial growth in first 16 yrs and become sexually mature between 7-12 yrs; males sexually mature within 5 yrs and show a sharp decline in growth rates after maturing; on average within snake species, A. arafurae mature very slowly; though pressures are being applied to populations of this snake such as low reproduction rates, sought after in New Guinea for its hide, water pollution and looked upon as an important traditional food item for aborigines that highly prize and seek out pregnant females, A. arafurae is not currently listed as threatened.
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| 1. Ceylonese pipe snake ~ C. maculatus |
Ceylonese Pipe Snake
Family: Cylindrophiidae
Genus: Cylindrophis
Species: Cylindrophis maculatus
Length: 30-65cm/11.81-25.59in
Weight: ~19.5g/0.69oz
Longevity: Unknown
Name Origin: Cylindrophis maculatus ~ Cylindr originates from the Greek word, kulindros meaning 'cylinder'; ophis is Greek for 'snake'; maculatus is Latin for 'spotted' in reference to large reddish brown spots; altogether refers to 'cylindrical spotted snake'.
Distribution: Endemic to island of Sri Lanka up to 1,000m/3281ft asl; inhabits island's all 3 climate zones; prefers closed forests with loose packed ground, leaf litter, felled logs and rocks to shelter or hide under.
Description: Known as 'Depath naya' in Sri Lankan technical circles; closest relation is the extinct Cretaceous snake, Kelyophis hechti; both snake species are listed under the suborder, Alethenophidia, but in differing families with genus, Kelyophis listed under Nigerophiidae; general physical characteristics are smooth dorsal, glossy, iridescent, & overlapped scales with a broadly rounded snout, no neck distinction and a very short tail, in particular for snakes which begins at cloaca ending at tip; though tail is broad, tail tip is pointed arising myths that snake can falsely sting; body gives appearance of a cylinder or tube; has small eyes with pupils slightly vertically elliptical; a pair of nostrils each sitting in a
Distribution: Endemic to island of Sri Lanka up to 1,000m/3281ft asl; inhabits island's all 3 climate zones; prefers closed forests with loose packed ground, leaf litter, felled logs and rocks to shelter or hide under.
Description: Known as 'Depath naya' in Sri Lankan technical circles; closest relation is the extinct Cretaceous snake, Kelyophis hechti; both snake species are listed under the suborder, Alethenophidia, but in differing families with genus, Kelyophis listed under Nigerophiidae; general physical characteristics are smooth dorsal, glossy, iridescent, & overlapped scales with a broadly rounded snout, no neck distinction and a very short tail, in particular for snakes which begins at cloaca ending at tip; though tail is broad, tail tip is pointed arising myths that snake can falsely sting; body gives appearance of a cylinder or tube; has small eyes with pupils slightly vertically elliptical; a pair of nostrils each sitting in a
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| 2. Note short tail beyond cloaca |
single scale; cloaca scale is divided; possesses maxillary, palatine, pterygoid and mandibular teeth that are anododont in dentition; overall coloration has dorsum colors of either an opaque brick red or brownish orange with a black network enclosing 35-55 rowed spots usually with 2 dominant lighter nuchal spots that may be totally ringed; dorsal head & tail normally black; ventrum is either creamish, white or pink with black barring creating a variegated pattern; juveniles are similarly patterned, but lighter in shades; currently there are no listed subspecies.
Diet: This snake cannot articulate and distend its mouth in accommodating larger prey as most snakes can, so preys on less bulky but long and thin prey; utilizes backbone in consuming prey; while swallowing, part way with some of victim still hanging out from mouth, snake will shut the mouth, curve its backbone back and forth causing head to shoot forward engulfing more of prey; main food items are fossorial such as earthworms, caecilians & amphisbaenids; also consumes scincid lizards and smaller colubrid (Aspidura) & uropeltid (Rhinophis) snakes; juveniles take insects and small amphibians; will consume prey longer than themselves; is a constrictor but only fully constricts larger prey; smaller prey it will coil around, but only to hold until the mouth can reach the head to begin swallowing victim still alive; predation comes from birds of prey, shorebirds, larger lizards and snakes, in particular the Ceylon krait snake, Bungarus ceylonicus.
Diet: This snake cannot articulate and distend its mouth in accommodating larger prey as most snakes can, so preys on less bulky but long and thin prey; utilizes backbone in consuming prey; while swallowing, part way with some of victim still hanging out from mouth, snake will shut the mouth, curve its backbone back and forth causing head to shoot forward engulfing more of prey; main food items are fossorial such as earthworms, caecilians & amphisbaenids; also consumes scincid lizards and smaller colubrid (Aspidura) & uropeltid (Rhinophis) snakes; juveniles take insects and small amphibians; will consume prey longer than themselves; is a constrictor but only fully constricts larger prey; smaller prey it will coil around, but only to hold until the mouth can reach the head to begin swallowing victim still alive; predation comes from birds of prey, shorebirds, larger lizards and snakes, in particular the Ceylon krait snake, Bungarus ceylonicus.
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| 3. Tail raising & curling |
Habits: C. maculatus in general is an unusual snake, but one of its more odd behaviors is its defense tactics; has ability to distend posterior ribs flattening the back half of body; simultaneously raises and curls tail displaying underside, then waving posterior end as cobras do in defense warnings; the tail appears as a false head and can confuse predators; if so much as touched by a perceivable animal threat, will exude a yellow acrid semiliquid viscous fluid from paired anal glands; other than these defensive moves will passively hide its real head beneath its lowest coil, but does not attempt to escape and does not utilize teeth to defend; is semi-fossorial and burrows with its stout rostral scale; burrows wide enough to enable it to turn around; can swiftly tunnel in moist loose soils; forages mostly at night so is nocturnal; spends daylight hours either burrowed or underneath ground litter on surface; after heavy rains will frequent surface actively; when mobile on surface can
travel just as fast going backwards as forwards; on surface movement is erratic and awkward due to not possessing long ventral scales for gripping; this snake is viviparous with female possessing a placenta and egg yolk to accommodate fully developed fetus; young are retained until reaching a very unusual degree of development; period of gestation is not known; litters consist of 2-7 young; at birth, neonates are 127-137mm/5-5.40in; in first year of life these snakes grow rapidly reaching 272mm/10.71in; being endemic and isolated to an island while exposed to pollution and dumping grounds, C. maculatus populations are potentially being threatened, although this snake is not currently listed under any threatened category.
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| 4. Female with 2 neonates |
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| 1. Trans-Pecos rat snake ~ B. subocularis |
Trans-Pecos Rat Snake
Family: Colubridae
Genus: Bogertophis
Species: Bogertophis subocularis
Length: 1.0-1.7m/3.3-5.61ft
Weight: ~178-302.5g/6.28-10.67oz
Longevity: Ave: 10yrs, but up to 20-25yrs
Name Origin: Bogertophis subocularis ~ Bogertophis honors Charles Mitchill Bogert, an herpetologist who worked on the systematics of colubrids; all Latin rooted sub means 'below', oculus refers to 'eye', aris meaning 'in having'; altogether refers to, 'Bogert's snake having lorilabial scales below eyes'.
Distribution: Ranges in south-central New Mexico, within the Trans-Pecos and Big Bend areas of Texas southwards into the state of Durango, Mexico; prefers arid-semi arid zones in agave, creosote bush, ocotillo slopes and rocky areas dominated by low growth shrubs and trees.
Description: Is an elegant long & slender snake belonging to the New world Elaphe (rat snake) group; scales slightly keeled and anal scale is divided; possesses subocular scale row lying in contact with eye and directly below between eyes and upper labial lip scales; has large
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| 2. Note large eye & suboculars |
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| 3. Ventrum showing sheen |
Diet: Once designated under the genus Elaphe or rat snakes due to rodents being the main course of consumption, it was later found that lizards are the major food item for B. subocularis in the wilds; Besides lizards, will also take rodents such as deer mice & white throated wood rat, sciurids such as ground squirrels, young birds such as cliff swallows & roadrunners and has been observed capturing bats as the mammals fly out from cave entrances or probing nooks & crannies where bats roost; juveniles chiefly feed on lizards; may feed on very large animals, but apparently the ingested hump does not hamper locomotion or the ability to climb in adults; juveniles develop habit of eating large prey and they do have difficulty in maneuvering and may simply just roll from side to side with the large lump until digested; natural predators are birds of prey such as owls & roadrunners; where ranges intersperse, helodermatids may locate nest sites and dig up eggs to consume.
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| 4. Lft: blonde variant; Mid: mixed coloration; Rt: silver variant |
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| 5. An adept climber |
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| 1. Sonoran shovel-nosed ~ C. palarostris |
Sonoran Shovel-nosed Snake
Family: Colubridae
Genus: Chionactis
Species: Chionactis palarostris
Length: 25-43cm/9.84-17in total length (TL)
Weight: 6.6-25.8g/0.23-0.91oz
Longevity: Estimate: 4.5-9yrs in wilds
Name Origin: Chionactis palarostris ~ Chion is Greek for 'snow'; aktis is also Greek meaning 'ray of beam'; pala is Latin for 'shovel' and the Latin root word rostris (rostrum) is in reference to 'nose' or 'beak'; altogether refers to, 'beam of ray in snow shovel nosed snake' alluding to snake coloration and upper jaw overbite.
Distribution: Ranges up to the extreme south central portion of Arizona in the Organ Pipe Cactus National Monument and adjacent area, extending south down through Mexico along Gulf of California to southern extreme of Hermosillo, Mexico in central Sonora; prefers sandy to sandy-gravelly soils and is commonly found in silty washes, hilly terrain and rocky bajadas from elevations of sea level to 760m/2500ft.
Description: Scales smooth & glossy; small rounded pupil; snout is slightly convex and flatter than seen in most snakes; jaw is countersunk; possesses nasal plugs; belly is slightly concave; these attributes equip the snake for tunneling through loose sandy & gravely soils; dorsal scales in 15 rows; caudal plate scale divided; ventral scales number between 140-160 while caudal scales (scalation past anus) number 42-48; body ground coloration is from cream yellow to light yellow with up to 20 black crossbands interrupted by soft-edged red saddle bands that do not extend past sides to ventrum; last 1-5 anterior black bands do not encircle body ending on sides; red & black banding are roughly equal in width; ventrum is creamy;
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| 2. Note overbite |
Diet: Is considered an insectivore feeding on insects, moth buried pupae; centipedes, spiders & scorpions; consuming scorpions can be a tricky business; the snake seizes scorpion at base of stinger, takes hold and backs into sand aligning scorpion into a U-shaped bend; once scorpion is folded, begins consuming prey until only claws & stinger are all that remains which are then consumed in one gulped swallow; tends to abstain from insects with hard exoskeletons like beetles; predators include birds of prey such as great horned owls, roadrunners & loggerhead shrikes and reptiles such as coral snakes.
Habits: Mainly nocturnal and crepuscular, hiding by day in burrows, underneath ground objects or just under the ground surface in shade; displays unique behavior known as 'sand swimming' in utilizing sideways swaying motions to literally swim across or just under sand;
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| 3. Typical C. palarostris habitat |
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| 4. Note red bands do not reach ventrum |
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| 1. Texas coral ~ Micrurus tener |
Texas Coral Snake
Family: Elapidae
Genus: Micrurus
Species: Micrurus tener
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Venomous
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Syndrome: Micrurus species are the most toxic snakes in N. America per mg of dried venom weight; Texas coral snake's neurotoxic venom composed of 49 peptides is capable of inflicting lung & heart failure due to a fatal bite. Symptoms may not appear until 12 hrs after bite, affecting nerve synapses and junctions causing misfires. Afflictions include tremors, speaking & swallowing difficulties, drooping eyelids, respiratory depression, pulmonary & cardiac arrest. In surviving Micrurus envenomation, recovery is complete with no side effects. Venom is being researched to combat cancer cells and AIDS.
Length: 61-100cm/24-40in
Weight: 5.75-9.40g/0.20-0.33oz
Weight: 5.75-9.40g/0.20-0.33oz
Longevity: Up to 20yrs; female of unknown age survived 18yrs & 4 mths at Fort Worth Zoo
Name Origin: Micrurus tener ~ Mikros is Greek for 'small'; oura is Greek for 'tail' with both referring to size of tail; tener is Latin for 'softness' or 'delicacy' as contrast in size to M. fulvius; altogether refers to, 'the small tail and more slender coral snake'.
Distribution: Geographic range for U.S. is Texas, Arkansas & Louisiana west of Mississippi extending southwards into Mexico in the states of Tamaulipus, San Luis Potosi`, Guanajuato, Quere`taro & Morelos; prefers forests with plenty of organic ground material & loose soils; exists in low lying areas through wooded canyons to rocky hillsides; normally is found near water sources near sea level to 2000m/6600ft.
Description: Is a small to medium sized slender snake with smooth scales; small rounded black eyes & pupils; head is rounded; a pair of small fangs are set in front of upper mouth; are not as pointed or sharp as viper fangs and may visually appear as blunted; venom is injected from opened tips; fangs measure 3.18mm or 1/8in; possesses strong muscle jaws; overall coloration is tri-banded in a black, yellow and red pattern encircling body; snout is always black with yellow head, neck is black ending just before parietal scales; body banding then sequences in
Name Origin: Micrurus tener ~ Mikros is Greek for 'small'; oura is Greek for 'tail' with both referring to size of tail; tener is Latin for 'softness' or 'delicacy' as contrast in size to M. fulvius; altogether refers to, 'the small tail and more slender coral snake'.
Distribution: Geographic range for U.S. is Texas, Arkansas & Louisiana west of Mississippi extending southwards into Mexico in the states of Tamaulipus, San Luis Potosi`, Guanajuato, Quere`taro & Morelos; prefers forests with plenty of organic ground material & loose soils; exists in low lying areas through wooded canyons to rocky hillsides; normally is found near water sources near sea level to 2000m/6600ft.
Description: Is a small to medium sized slender snake with smooth scales; small rounded black eyes & pupils; head is rounded; a pair of small fangs are set in front of upper mouth; are not as pointed or sharp as viper fangs and may visually appear as blunted; venom is injected from opened tips; fangs measure 3.18mm or 1/8in; possesses strong muscle jaws; overall coloration is tri-banded in a black, yellow and red pattern encircling body; snout is always black with yellow head, neck is black ending just before parietal scales; body banding then sequences in
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| 2. Wild amelanistic specimen |
red, yellow & black banding; red bands usually dotted with random black scales; vivid coloration is advertisement for predators to beware, but unfortunately color scheme actually attracts adult humans & children; though uncommon, melanistic (dominant black pigmentation), amelanistic (lacking black pigmentation) and anerythrisitic (lacking red pigmentation) specimens do occur in the wilds; some taxonomic works express that 4 subspecies exist due to scale variation in numbering; they are M. t. tener, M. t. fitzingeri, M. t. maculatus & M. t. microgalbineus.
Diet: Has been reported to prey on large insects, anurans (various frogs), lacertilians (various lizards), but is known basically to be ophiophagus (snake-eating); eats a wide variety of colubrids along with viperid juveniles (Agkistrodon piscivorus & Agkistrodon contortrix); adult M. tener will also consume juvenile Texas coral snakes; juveniles primarily consume
Diet: Has been reported to prey on large insects, anurans (various frogs), lacertilians (various lizards), but is known basically to be ophiophagus (snake-eating); eats a wide variety of colubrids along with viperid juveniles (Agkistrodon piscivorus & Agkistrodon contortrix); adult M. tener will also consume juvenile Texas coral snakes; juveniles primarily consume
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| 3. Eating juvenile copperhead |
arthropods, but may also consume small ground snakes such as the genus, Sonora; predators include adult American bullfrogs (Rana catesbeiana), kingsnakes (Lampropeltis getula), adult Texas coral snakes, opossums (Didelphis marsupialis) and hawks, such as Buteo jamaicensis).
Habits: Along with kraits, mambas and cobras belonging to the family Elapidae, coral snakes possess a highly venomous neurotoxin; coral snakes are called as such because of the coloration; M. tener, unlike other elapids though is normally shy & retiring preferring retreat rather than confrontation; although this snake has a mild temperament, it is still very DANGEROUS; I once accidentally came across one on a hilly, grassy and rocky knoll near Lake Travis just north of Austin, Texas; it was shy, but once thoroughly provoked reacted with hyper-quick reflexes; many authorities state that the mouth is too small to deliver a bite sufficient enough to envenomate a human due to anatomy; it is true they first must gain hold of then chew to deliver venom into a wound, but with lightning quick movement, a mouth that can be opened 5x its shut size, strong jaws and fangs that can be pressed into flesh
Habits: Along with kraits, mambas and cobras belonging to the family Elapidae, coral snakes possess a highly venomous neurotoxin; coral snakes are called as such because of the coloration; M. tener, unlike other elapids though is normally shy & retiring preferring retreat rather than confrontation; although this snake has a mild temperament, it is still very DANGEROUS; I once accidentally came across one on a hilly, grassy and rocky knoll near Lake Travis just north of Austin, Texas; it was shy, but once thoroughly provoked reacted with hyper-quick reflexes; many authorities state that the mouth is too small to deliver a bite sufficient enough to envenomate a human due to anatomy; it is true they first must gain hold of then chew to deliver venom into a wound, but with lightning quick movement, a mouth that can be opened 5x its shut size, strong jaws and fangs that can be pressed into flesh
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| 4. Fang under a scope |
6.35mm/0.25in, penetration & envenomation can occur on an human victim of any size; human skin is much softer than its natural reptilian prey; when this snake bites it clings on like a bulldog onto steak; the average dry lethal dose of M. tener venom for an adult human is 10-12 mg/.00035-.0004oz; Micrurus gallicus, an extinct European coral snake closely related to M. tener, roamed central Europe during Miocene 21-11.5 mya; M. gallicus first appeared when rodent speciation spread; Texas coral snake is primarily fossorial, crepuscular and diurnal actively foraging under forest litter, under ground objects such as rocks & fallen logs and through loose sandy soils; retires in burrows or rock crevices after dusk emerging during sunrise; returns to same retreat; is most active on ground surface during spring months; females are more active than males in fall months in replenishing fat reserves after gravid & ovipositing periods; also
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| 5. The snake as beautiful as coral |
becomes particularly active on surface after heavy rains; in northern range (U.S.) hibernates during colder months and is active year round in southern range (Mexico); instead of basking, tropical ancestory evolving ability to hibernate allowed M. tener to survive in U.S. range; mating occurs from April to March; females lay down pheromone trails that males pick up to locate them; in courting, male flicks tongue over dorsal midbody of female, raises head & neck at a 45° angle, then tilts head down touching female's back with his snout; in this position, he quickly rubs snout along her back nearly to her head, then back down the back stopping within her vent; ~ 40% of time this is reversed rubbing back first from vent to head; as long as females obliges male's back rubbing, he aligns their bodies together where vents meet at 30° angles; he then thrusts everted hemipensis into her and copulates; In June & early July, gravid females oviposit a clutch of 2-12 eggs in loose sands or rotting log debris; neonates hatch 2 months later measuring ~ 22cm/8.66in long; males attain spermiogenesis in 12-21 months when are ~ 40cm/15.75in SVL; females attain sexual maturity in 12-21 months after reaching 50-55cm/19.7-21.7in SVL; with fixed frontal fangs, this snake is proteroglyphous; habitat destruction and road kills, which can be numerous as coral snakes are not adept in traversing road surfaces tending to attempt sidewinding, are a threat to this snake; irregardless, M. tener is not listed as threatened due to its wide range in distribution.
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| 1. Gold-ringed cat snake ~ B. dendrophilia |
Gold-ringed Cat Snake
Family: Colubridae
Genus: Boiga
Species: Boiga dendrophilia
Species: Boiga dendrophilia
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| Venomous |
Many species make-up the genus, Boiga and are from mild to moderately dangerous rear fanged snakes. B. dendrophilia bites do not lead to fatality directly, but serious reactions will occur if envenomated with this snake's hemotoxic & neurotoxic venom. A considered lethal intravenous dose is only 4.9 micrograms per gram. Fortunately this large and aggressive snake carries minimum venom dosage levels and must take time chewing to deliver venom.
Length: 1.8-2.4m/6-8ft; Maximum: 2.5m/8.25ft
Weight: 1.70-2.27kg/3.75-5.0lbs (Dependent upon Dendrophilia ssp.)
Longevity: 13-17yrs
Name Origin: Boiga dendrophilia ~ The genus, Boiga is latinized in honor of German naturalist, Heinrich Boie, who was first to describe 3 Boiga species listing them originally under genus, Dipsas; dendros is derived from Greek meaning 'wood'; philos is also Greek referring to 'dear friend'; altogether refers to 'Boie's snake endeared to an arboreal lifestyle'.
Distribution: Subspecies give this snake a wide range throughout southeast Asia from India to the Philippines with concentrated populations in Indonesia, Peninsular Malaysia, Singapore & Indo China; prefers coastal regions of mangrove stands near waterways and riverines in tropical rainforests.
Name Origin: Boiga dendrophilia ~ The genus, Boiga is latinized in honor of German naturalist, Heinrich Boie, who was first to describe 3 Boiga species listing them originally under genus, Dipsas; dendros is derived from Greek meaning 'wood'; philos is also Greek referring to 'dear friend'; altogether refers to 'Boie's snake endeared to an arboreal lifestyle'.
Distribution: Subspecies give this snake a wide range throughout southeast Asia from India to the Philippines with concentrated populations in Indonesia, Peninsular Malaysia, Singapore & Indo China; prefers coastal regions of mangrove stands near waterways and riverines in tropical rainforests.
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| 2. Note cat-eye & yellow labials |
Description: Is a long & slender snake; head is wider than neck due to jaw muscles; similar to a cat's eye, pupil is dark & vertically elliptical; iris is a dark gray; supralabials & infralabials (lip scales) are always yellow with black borders except in the adult subspecies B. d. gemmicincta; vertebral scale rows are enlarged; anal scale is single; anterior & posterior palantine teeth are relatively same size; maxillary teeth located on both upper maxilla bones are slightly recurved; 2-3 enlarged grooved posterior maxillary teeth on each upper side of mouth serve as fangs for venom delivery; typical cat-eyed snake coloration is
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| 3. B. d. gemmicincta |
golden yellow body rings on a black background; ventrum is a bluish black; throat is always yellow; main difference between subspecies is devoid of yellow rings; rings may completely surround body including ventrum, or reduced confined to flanks in not extending over dorsum; subspecies, B. d. gemmicinctas is an exception; as a juvenile it is ringed with the golden yellow bars, but becomes totally black in adulthood as rings fade away upon aging; within the species, B. dendrophila there are 8 subspecies currently recognized; they are: B. d. annectens, B. d. divergens, B. d. gemmicincta, B. d. latifasciata, B. d. levitoni, B. d. melanota, B. d. multicincta & B.d. occidentalis.
Diet: Chief prey is small birds; supplements diet with bird eggs, frogs, reptiles (lizards & other snakes), rodents, bats and fish; main predator is monitor lizards; if hungry enough, due to high metabolic rates, will resort to cannibalism of own species.
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| 4. Note grooved fangs |
Habits: Is strictly active nocturnally and is ill tempered and aggressive during dark hours; by day remains coiled up in tree branches usually above a body of water; during daylight is almost catatonic and listless; grooved fangs are rearward therefore are opisthoglyphous; potentially is the most dangerous of Boiga snakes; B. dendrophilia venom, known as denmotoxin, is a monomeric peptide consisting of 77 amino acid residues with 5 disulfide bridges; neurotoxic component of venom structure is bird prey specific having most effect on avian prey's nerve system; hemotoxic structure does do damage to other animal tissues, including humans; if repercussion to envenomation includes allergic reaction to proteins, human fatality could
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| 5. B. dendrophilia envenomation |
ensue without immediate medical attention; denmotoxin is secreted by the duvernoy's gland, travels through a duct to tissue just above grooved fang, then trickles down groove into wound; denmotoxin is non-Newtonian in being viscuous, but surface tension is such that wound tissue of victim draws in & absorbs venom; metabolism is higher than most snakes, so feeds more often, in which makes the snake more aggressive when foraging at night and more calm by day to conserve energy; is arboreal spending most of time in trees and large shrubs, but will come down to ground surface when foraging; is an adept swimmer and will actively hunt fish; in defense will scurry to the nearest tree, or if feeling cornered will raise one-third of body in S-shapes striking the air in direction of
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| 6. Defensive posturing |
intruder; may mate year round, but preferentially when temperature is a constant 22-24 °C/71.6-75.2 °F for 2-3 months with high humidity; females are oviparous laying 5-15 eggs per clutch with up to 20 having been recorded; clutches are oviposited in and among ground leaf litter & surface debris; females may lay up to 3 clutches per year and may store male sperm for delayed fertilization; incubation period is 95-110 days; hatchlings utilize an egg tooth for cracking out of the egg shell and measure ~ 30cm/11.81in; juveniles become sexually mature at 3 years; heavy infestation can occur with parasites such as mouth flukes and reptile ticks; in their range, B. dendrophilia sp. & ssp. are common and are not considered threatened.
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| 1.Olive sea snake ~ A. laevis |
Olive Sea Snake
Family: Hydrophiidae
Subfamily: Hydrophiinae
Genus: Aipysurus
Species: Aipysurus laevis
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| Venomous |
Syndrome: All hydrophiids are highly venomous due to active neurotoxic and nephrotoxic (kidney) venom. A. laevis venom also has myotoxic components that destroy mitochondrial fibers within cells. Initial bite is painless whether a dry bite (no envenomation) or envenomous, although a fang sometimes is left behind in the wound. Within 30 minutes, headache, sensation of tongue thickening, thirst, sweating and vomiting occurs. After 30 post minutes of envenomation, in the next 1-3 hours, victim will experience aching, tenderness and stiffness of muscles due to rhabdoyolysis (rapid breakdown of skeletal muscles). Progressive flaccid paralysis then follows in sequence from loss in control of voluntary muscles, inability to swallow and finally respiration difficulties which may prove fatal. If a victim survives paralysis, after 3-12 hours renal kidney failure and cardiac arrest will occur causing fatality.
Length: Ave: 1.7m/5.58ft total length (TL); Max: 2.19m/7.22ft TL
Weight: Up to 3kg/
Longevity: Up to 15 yrs
Name Origin: Aipysurus laevis ~ Aipy is Greek for 'high'; surus is Latin but Greek rooted for 'tail'; laevis is Latin meaning 'smooth' or 'agile'; altogether refers to, 'agile paddled-tailed sea snake'.
Distribution: Has a wide Indo-Pacific range found in the Timor & Coral Seas along the northern coastline of Australia to New Guinea; prefers coral reefs and rocky shoals along coastal waterways; rarely ventures beyond 45m/148.5ft in water depth.
Description: There has been much discussion and debate on the taxonomy & classification of sea snakes; some still list them under the (1) family, Elapidae, others group all sea snakes under the (2) family, Hydrophiidae, while a few classify them under the (3) family, Hydrophiidae with the 2 subfamilies, Hydrophiinae & Laticaudinae; I choose the latter of the 3 classification schemes; sea snakes are closely related to land dwelling elapids in being first cousins, but morphologies, physiologies and molecular genetics in migrating to a watery environment are distinct enough in their evolution from land to sea to list them under separate orders; subfamilies are also in my opinion deemed appropriate, for while Hydrophiinae members are wholly aquatic, the sea kraits (Laticaudinae) are not; sea kraits are in transition between the sea and land in still maintaining the elapid line of being oviparous, laying eggs on land and have not developed the paddle or rudder posterior end as fully aquatic Hydrophiinae members have; Laticaudinae are at home on land or sea, where Hydrophiinae physiological evolvement is strictly aquatic and cannot maneuver on land;
all Hydrophiinae are ovoviviparous giving birth at sea; A. laevis is the largest of hydrophids; anterior quarter is round; posterior three-quarters of body is vertically flattened sideways with tail appearing paddle-shaped with raised edge running along each side; 21-25 dorsal smooth scale rows; caudal (anal) scale is divided; 25-35 subcaudals are single; cephalic (head) scales are enlarged; head is short & of equal width with stocky body; possesses nasal flap valves for diving, preventing water ingress; has the typical bifurcated serpentine tongue to collect molecules in water for analysis by olfactory sensors in Jacobson's organ; eyes are prominent with rounded pupils; paired fangs are fixed in upper front of mouth (proteroglyphous); sexual dimorphism exists with females larger than males; dorsum coloration may be creamy gray or light brown often with random darker scales; ventrum is normally creamy; head is a medium brown; in bright light, coloration may take on a olive brown complexion; juveniles exhibit a much darker brown dorsum with creamy zig-zag striping extending from sides up and over dorsum; some authors list the Shark Bay sea snake, Aipysurus pooleorum as a subspecies, but due to differences in molecular genetics, it is being elevated & treated as a distinct species here.
Diet: A. laevis has a multi-varied diet consisting of small coral reef fish, small eels, crustaceans such as shrimp, prawn & crabs; curiously for a very venomous snake that needs to disable prey quickly before it swims too far into the ocean depths, they also consume a fair amount of fish eggs; are preyed upon by tiger sharks (Galeocerdo cuvier) and can fall victim to avian predation when resting on surface.
Habits: The olive sea snake is not shy but very curious attracted to shiny and lighted objects; most resources suggest it is not aggressive and divers have swam with them wrapped around their arms and even necks for many meters without any attempts of the snake to bite; if provoked though it will bite; this behavior, I do not recommend to the novice diver as the risks of being bitten is too great with the potentially lethal bite of venom that is highly potent per unit concentrate; larger females are more dangerous due to higher venom yield; most fatalities occur with fishermen mishandling fish nets that trapped the snake as part of the haul; A. laevis is active day or night, but appears to be more nocturnal as foraging activity and more
excited aggressive display is heightened; forages by actively seeking out prey buried in sand or poking head into crevices of coral and rock; typical submerged time is 16 minutes but may stay immersed over 30 minutes; can travel underwater in excess of 500m/1650ft before being forced to surface for air; on the surface A. laevis takes 1-3 breaths then will either immediately dive if active or if tired, remain on surface to rest with head above water; tail is equipped with photoreceptors that detect light movement; what photoreceptor advantage is, is not clear, but at night this snake will move aggressively towards a moving light source, therefore when actively hunting with head inside rock & coral crevices, photoreception allows the snake to detect potential threats moving in from its back side; resting is usually under submersed ledges; except for the divided anal scale having a prominent keel on each half, the snake is smooth for swimming; at
times some may exhibit colonization of alga or barnacle growth; sublingual glands located at base of tongue filter salt from bloodstream where it is expelled by the tongue back out into open water; in a tropical setting, reproduction is year round, but each female requires a full year for adipose tissue renewal, so individual females are biennial in mating; only 50% of females at one time are active in breeding; courtship takes place with a moving ballet consisting of 1 receptive female with 1-3 males encircling her and touching her with their tongues in frenzied overtones; once female picks a winning male, they both settle down to the bottom and copulate; during mating process, couple is completely coiled around one another with male tapping female's neck with his head; female is gravid ~ 9 months giving birth on average to 3 offspring; range is from 1 to 5 offspring; males reach sexual maturity in 3 years measuring ~ 68cm/27in; females mature later in 4-5 years measuring 80cm/31.5in; due to inability to maneuver on land, beaching is probably the highest mortality cause; mining pollution runoff and trapped in weighted fish nets also contribute to mortality, but as a whole being the most observed in sea snake encounters, A. laevis is not considered as threatened.
Golden Lancehead
Family: Viperidae
Genus: Bothrops
Species: Bothrops insularis
Syndrome: Envenomation from vipers in the genus, Bothrops are responsible for more human fatalities than any other group of snakes in N. America & S. America combined. Due to very small population size, there have been no reports of human envenomation by B. insularis, but from chemical analysis, its venom is regarded as 5x more potent than that of B. jararaca, a lanchead responsible for most reported human deaths with venom having a LD50 of 1.25mg/kg intravenous. With this in mind, B. insularis venom is the fastest acting of all Bothrops. Primarily hemotoxic, symptoms from envenomation would include: localized pain, swelling, bloody vomiting & urination, blood blister formation, intestinal bleeding, severe necrosis of muscle tissue, kidney failure and brain hemorrhage. Essentially, the victim is internally predigested.
Length: Ave TL ~ 70cm/27.55in; Max~ 120cm/47.24in
Weight: From 3-7 yrs ~ 180-1190g/6.35-42oz
Longevity: Not quantified, but at least up to 7 yrs
Name Origin: Bothrops insularis ~ Bothros is Greek for 'pits'; ops is also Greek meaning 'face'; insularis is Latin for 'insular' rooted from insula pertaining to 'island'; altogether refers to, 'pitted face island viper'.
Distribution: Off the coast of southeastern Brazil out from the shore of Sao Paulo sits the 0.43 kilometer squared island of Queimada Grand Island; island was formed 11,000 years ago from the rise in oceanic levels during end of last ice age separating it from mainland Brazil; the
island is the sole habitat of B. insularis which is found nowhere else; the island is in a moist tropical forest zone.
Description: B. insularis & B. jararaca, inhabiting mainland Brazil, both arose from same base ancestor (which may have been original B. jararaca species before evolvement), but were cut off from each other during oceanic rise evolving differently in varying environments; lance shaped head is distinct to genus Bothrops; head is triangularly elongate ending pointed at snout; B. insularis venom (primarily hemotoxic) is most toxic of all Bothrops; is a diverse multifunctional collection of proteins and peptides that play havoc on normal metabolic cellular activity; venom contains a metalloproteinase (protease enzyme in which mechanism is catalyzed by a metallic ion) that bind to and destroy normal protein function; juveniles under 15 months, venom is more intense in myotoxic effects and blood coagulation; B. insularis fangs are shorter than b. jararaca; loreal pits (heat sensory pits) are distinct between nostril & eye; Bothrops possess short tails, but B.
insularis tail is long and tapered; dorsal scales are keeled; caudal (anal) scale divided; lance shaped head is very distinct from body; sexual dimorphism is evident in female being considerably larger than male; overall dorsum coloration is a light yellowish brown at times with individuals having darker brown zigzag bar markings across back extending to sides; due to ineffective thermoregulation leading to poor circulation, sometimes results in yellowish color appearing darker; tail tip normally is dark; ventrum is uniform in a pale yellowish creme coloration; there are no recognized subspecies.
Diet: Due to limited range in being endemic to a tiny island, food source is greatly limited for this snake; no mammals exist on the island, so chief prey for adults is migratory birds utilizing island for rest stops; perching birds are chief prey supplemented occasionally by amphibians & lizards; at times will resort to cannibalizing juveniles; juveniles survive off invertebrates such as insects, spiders, centipedes & scorpions; both adults & young may prey off other small snake species; for adults are no known natural predators; possibly visiting large shore birds to island may take an adult; small juveniles have been observed being preyed on by large anurans, lizards and centipedes.
Length: Ave: 1.7m/5.58ft total length (TL); Max: 2.19m/7.22ft TL
Weight: Up to 3kg/
Longevity: Up to 15 yrs
Name Origin: Aipysurus laevis ~ Aipy is Greek for 'high'; surus is Latin but Greek rooted for 'tail'; laevis is Latin meaning 'smooth' or 'agile'; altogether refers to, 'agile paddled-tailed sea snake'.
Distribution: Has a wide Indo-Pacific range found in the Timor & Coral Seas along the northern coastline of Australia to New Guinea; prefers coral reefs and rocky shoals along coastal waterways; rarely ventures beyond 45m/148.5ft in water depth.
Description: There has been much discussion and debate on the taxonomy & classification of sea snakes; some still list them under the (1) family, Elapidae, others group all sea snakes under the (2) family, Hydrophiidae, while a few classify them under the (3) family, Hydrophiidae with the 2 subfamilies, Hydrophiinae & Laticaudinae; I choose the latter of the 3 classification schemes; sea snakes are closely related to land dwelling elapids in being first cousins, but morphologies, physiologies and molecular genetics in migrating to a watery environment are distinct enough in their evolution from land to sea to list them under separate orders; subfamilies are also in my opinion deemed appropriate, for while Hydrophiinae members are wholly aquatic, the sea kraits (Laticaudinae) are not; sea kraits are in transition between the sea and land in still maintaining the elapid line of being oviparous, laying eggs on land and have not developed the paddle or rudder posterior end as fully aquatic Hydrophiinae members have; Laticaudinae are at home on land or sea, where Hydrophiinae physiological evolvement is strictly aquatic and cannot maneuver on land;
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| 2. Note nose flaps |
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| 3. Juvenile |
Habits: The olive sea snake is not shy but very curious attracted to shiny and lighted objects; most resources suggest it is not aggressive and divers have swam with them wrapped around their arms and even necks for many meters without any attempts of the snake to bite; if provoked though it will bite; this behavior, I do not recommend to the novice diver as the risks of being bitten is too great with the potentially lethal bite of venom that is highly potent per unit concentrate; larger females are more dangerous due to higher venom yield; most fatalities occur with fishermen mishandling fish nets that trapped the snake as part of the haul; A. laevis is active day or night, but appears to be more nocturnal as foraging activity and more
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| 4. Actively foraging |
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| 5. Resting on surface |
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| 1. Golden lancehead ~ B. insularis |
Golden Lancehead
Family: Viperidae
Genus: Bothrops
Species: Bothrops insularis
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| Venomous |
Length: Ave TL ~ 70cm/27.55in; Max~ 120cm/47.24in
Weight: From 3-7 yrs ~ 180-1190g/6.35-42oz
Longevity: Not quantified, but at least up to 7 yrs
Name Origin: Bothrops insularis ~ Bothros is Greek for 'pits'; ops is also Greek meaning 'face'; insularis is Latin for 'insular' rooted from insula pertaining to 'island'; altogether refers to, 'pitted face island viper'.
Distribution: Off the coast of southeastern Brazil out from the shore of Sao Paulo sits the 0.43 kilometer squared island of Queimada Grand Island; island was formed 11,000 years ago from the rise in oceanic levels during end of last ice age separating it from mainland Brazil; the
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| 2. Queimada Grand Island |
Description: B. insularis & B. jararaca, inhabiting mainland Brazil, both arose from same base ancestor (which may have been original B. jararaca species before evolvement), but were cut off from each other during oceanic rise evolving differently in varying environments; lance shaped head is distinct to genus Bothrops; head is triangularly elongate ending pointed at snout; B. insularis venom (primarily hemotoxic) is most toxic of all Bothrops; is a diverse multifunctional collection of proteins and peptides that play havoc on normal metabolic cellular activity; venom contains a metalloproteinase (protease enzyme in which mechanism is catalyzed by a metallic ion) that bind to and destroy normal protein function; juveniles under 15 months, venom is more intense in myotoxic effects and blood coagulation; B. insularis fangs are shorter than b. jararaca; loreal pits (heat sensory pits) are distinct between nostril & eye; Bothrops possess short tails, but B.
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| 3. Note loreal pit (heat sensor) |
Diet: Due to limited range in being endemic to a tiny island, food source is greatly limited for this snake; no mammals exist on the island, so chief prey for adults is migratory birds utilizing island for rest stops; perching birds are chief prey supplemented occasionally by amphibians & lizards; at times will resort to cannibalizing juveniles; juveniles survive off invertebrates such as insects, spiders, centipedes & scorpions; both adults & young may prey off other small snake species; for adults are no known natural predators; possibly visiting large shore birds to island may take an adult; small juveniles have been observed being preyed on by large anurans, lizards and centipedes.
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| 4. Seizing chief prey, perching birds |
Habits: Vipers are opisthoglyphous ambush predators striking with long paired fangs then releasing and thereupon lie in wait for venom to take effect; this keeps the serpent safe from struggling prey; normally nocturnal, they then rely more on heat sensing to detect dying prey's movements and scent for the death trail; due to only chief prey being found on island are small birds, B. insularis has evolved highly potent and quick acting venom; this was necessary, for a bird initially envenomated may fly off a few 30 meters or 100 yards and though it will die, would be a lost meal for the snake; besides quick acting venom, B. insularis also does not release its initial strike, instead holding onto the bird with the initial strike until it dies, then begins the process of swallowing; this snake is still an ambush predator lying in wait in trees and uses caudal (tail) luring to attract birds within range to strike; many individuals have pieces of tail missing attributed to birds pecking it in thinking of it as a potential invertebrate larvae or worm meal; as in all vipers, strike is lightning quick performed in milliseconds; ambush position is usually in a coiled formation with head held up and tail near head; is nocturnal & diurnal and arboreal & terrestrial being more arboreal during daylight to capture birds and more terrestrial during darkness in seeking anurans or other reptiles; also seek shelter from weather under leaf litter or in rock crevices; is adept at climbing trees but tail is not prehensile; tail coloration is light in juveniles that would attract frogs & lizards more readily at night, while in adults, tail has darkened giving advantage to luring avian prey by day; main passerine birds captured are the Chilean Elaenia (Elaenia chilensis) & the thrush Turdus flavipes; the permanent resident wren,
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| 5. Ambush posturing |
Trogolodytes musculus, somehow evades predation and has a high density population on the island; avoidance of snake and with no other natural predators, the wren has an advantage living on the island; female uterine muscular twisting (UMT) begins in April ending in September; mating occurs from from July to Septmber; B. insularis is ovoviviparous giving live birth to 2-10 neonates (average: 7) in January the following year; intersexuality has only been found in 2 species of snakes throughout the animal kingdom; one is Pseudofimicia frontalis, while the other is B. insularis; population of B. insularis is 50% intersex (females possessing hemipenes), 40% males & 10% true females that are for most part infertile; all pregnant females are intersexes; this phenomena probably arose from confinement of population on tiny island resorting to inbreeding; population on island is dense with estimation of 1 snake per every square meter in forested regions of island; even so, confined to this one very small island, habitat destruction by Brazilians in clearing area for self maintained lighthouse and intersex individuals may lead to sterility, this snake is listed as critically endangered.
Critically Endangered (3.1) IUCN
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| 1. Western Diamondback ~ C. atrox |
Western Diamondback Rattlesnake
Family: Viperidae
Genus: Crotalus
Species: Crotalus atrox
Syndrome: Primarily hemotoxic, C. atrox venom causes massive internal hemorrhaging by degenerating and destroying capillaries. Venom contains cytotoxins and peptide myotoxins that attack and cause the death of cells and tissue. Zinc metalloproteinases are present which is the main hemorrhagic component in disrupting microvessel function. The venom is also proteolytic in nature breaking down cellular protease structure by destroying tissue through intramolecular digestion. Initial symptoms include localized pain, abdominal pain, dizziness, diarrhea and possible convulsions. Resultant symptoms are internal bleeding, skeletal muscle necrosis, ischemia, secondary myonecrosis, heart damage, diaphragm disruption and possible fatality. LD50 is 2.72 mg/kg intravenous.
Length: 1.2-1.5m/3.9-4.9ft; infrequent up to 1.8m/5.9ft; record: 2.13m/6.99ft
Weight: 1.8-6.7kg/4.0-15.0lbs
Longevity: ~22-27yrs
Name Origin: Crotalus atrox ~ Krotalon is Greek for rattle; atrox is Latin meaning 'fierce' or 'savage' in reference to snake's disposition; altogether refers to, 'rattling fierce snake'.
Distribution: Range is in N. America, including southeast bottom portion of California westwards through southern half of Arizona & New Mexico through all of Oklahoma except along northern border ending through north central Arkansas; covers all of Texas except eastern portion where C. adamanteus range begins; southern Mexico range is in states of Hidalgo and northern Veracruz with disjunct populations in southern Veracruz & southeastern Oaxaca; found in arid to semiarid climates from plains, mountains, rocky canyons & river bluffs; sea level to 2,100m/7,000ft.
Description: This pit viper is heavy bodied with triangular head distinct from neck; pupils are vertically elliptical; most distinctive feature is tail rattle that begins as one button, adding another rattle segment after each shedding pushing button to tail tip; rattles are kertinous scales; after each shed, previous rattle becomes loosened but is interlocked and is not molted or sloughed off; dorsum scales are heavily keeled; caudal (anal) scale is undivided; possesses a pit between each eye and nostril utilizing infrared for heat sensory detection; 5mm/0.2in deep pit is with an outer and inner chamber separated by a thin membrane; heat information via loreal pits in crotalines is relayed to optic tectum; high resolution of heat detection is so efficient can detect heat variables down to 0.003 °C/.0054 °F; with this ability can locate prey blindfolded; opisthoglyphous fangs are long for deep penetration and are retractable based on maxilla bone that is hinged; sexual dimorphism exists where males become much larger after reaching sexual maturity; overall dorsum coloration is variable either being a yellowish gray, pale blue, rust tan or pinkish orange cast; rowed dorsal diamond shaped blotches are dark with pale white borders lining the back; diamond blotches are often peppered with darker speckled scales; tail is white with jet black rings; head is distinctly patterned with an angled pale oblique band from nostril to upper labials; another thinner light colored stripe extends back and down forming a steep angle from posterior of eye towards end of mouth's supralabials; ventrum is off-white and usually unmarked by patterns; there are no considered subspecies.
Diet: Chief prey are small mammals such as rodents (mice, rats, voles, gophers, prairie dogs, squirrels, etc.) and rabbits & jackrabbits; birds are also taken including mockingbirds, quail & burrowing owls; along with other reptiles in particular lizards are also taken; juveniles prey on
large insects such as grasshoppers & small reptiles; in one instance, in a muddy drying pool this species was observed consuming a fish that was confined to the pool; predation abounds with many animals considering this dangerous snake as a good meal; avian predators are hawks, owls, eagles & roadrunners; mammals include foxes, coyotes, bobcats, ringtail (Bassariscus astutus) and white-nosed coatimundi (Nasua narica) in southern range; kingsnakes are ophiphagous and immune to venom, actively seeks out C. atrox; in addition, antelope, bison & wild horses consider this snake as a threat and on intention will trample them; white-tailed deer in the Chisos Mountains of West Texas have been observed actively making a game out of it by lining up then each taking turn in jumping with all fours onto the hapless snake.
Habits: Outside of hibernating or mating, this is a solitary species; when threatened this snake will stand its ground; we like to anthropomorphize C. atrox by calling it ill tempered and savage, but in actuality it is simply defending itself from situations it perceives as life threatening; however, in the U.S. because of its defensive nature, more human fatalities each year are caused by C. atrox than any other snake; defensive posturing entails raising a third of anterior body with head directed at intruder while rattling tail; even though the snake cannot hear sound, it knows its adversaries can, so rattling is fair warning; can activate rattling up to 60 cycles/second; rattle warning may have evolved for the benefit of herding mammals, that could not see the camouflaged snake, but definitely could detect the rattle that it was nearby and not to tread too close; this saved the snake from being trampled and the mammal from being envenomated; venom evolved for acquiring prey and became secondary as a defense
mechanism; venom production is a costly affair in consuming energy, so in sizing prey, it calculates and measures the exact proper amount to utilize considering the prey's mass, therefore none is wasted; in protecting itself, it prefers warnings over dispensing venom; when striking for defense, the snake is more excited and may not inject any venom creating a dry strike, or it may inject its full load; when resting and approached will first remain motionless and silent; is primarily nocturnal when foraging, but is seasonally diurnal during cooler periods in seeking out new prey grounds; mostly by daylight, spends most of time coiled, sheltered under low lying shrub shade, piles of debris or rocks; also utilizes abandoned burrows of other animals; prairie dogs will craft earthen plugs to keep the snake from entering; is primarily crepuscular in early spring & late fall; hibernates in more northern range and brumates in more southern range during
colder months; hibernates alone or in communal dens with other crotalines and other snake species in rock crevices or ground holes; in northern most range, hibernation is underground; C. atrox can go for upwards to 2 years without eating; has ability to reduce energy expenditures up to 80%; body feeds off itself on stores of energy rich lipids; during long periods of not eating, snake still continues to grow; mating occurs in spring just after emergence from hibernation; males first do ritualized battles but never attempt to bite; fighters lift fore bodies ~80cm/31.5in and wrap around each other facing head to head; constant surging motions are directed at one another until one tires and moves off leaving the victor to mate; during courtship, while larger male crawls in jerk motions over her constantly flicking his tongue, female remains passive; male then proceeds to vigorously jerk his hind portion and presses tail firmly beneath the female's; female then lifts tail making cloacal contact where the male inserts one of his hemipenes; copulation will last 3-5 hrs; gestation lasts ~167 days; females are ovoviviparous producing 10-20 offspring; birthing may last up to 5 hrs; neonates break through thin egg membrane they're encased in while still inside the mother then immediately exit the cloaca; neonates measure 30cm/12in and stay with mother no more than a day (normally 3-5 hrs); young depart in search of food and to find shelter; mortality rates are high during winter months due to exposure, lack of success in capturing food and predation vulnerability; due to wide range in population this snake is not considered as threatened.
Distribution: Range is in N. America, including southeast bottom portion of California westwards through southern half of Arizona & New Mexico through all of Oklahoma except along northern border ending through north central Arkansas; covers all of Texas except eastern portion where C. adamanteus range begins; southern Mexico range is in states of Hidalgo and northern Veracruz with disjunct populations in southern Veracruz & southeastern Oaxaca; found in arid to semiarid climates from plains, mountains, rocky canyons & river bluffs; sea level to 2,100m/7,000ft.
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| 2. Note loreal pit & rattle |
Description: This pit viper is heavy bodied with triangular head distinct from neck; pupils are vertically elliptical; most distinctive feature is tail rattle that begins as one button, adding another rattle segment after each shedding pushing button to tail tip; rattles are kertinous scales; after each shed, previous rattle becomes loosened but is interlocked and is not molted or sloughed off; dorsum scales are heavily keeled; caudal (anal) scale is undivided; possesses a pit between each eye and nostril utilizing infrared for heat sensory detection; 5mm/0.2in deep pit is with an outer and inner chamber separated by a thin membrane; heat information via loreal pits in crotalines is relayed to optic tectum; high resolution of heat detection is so efficient can detect heat variables down to 0.003 °C/.0054 °F; with this ability can locate prey blindfolded; opisthoglyphous fangs are long for deep penetration and are retractable based on maxilla bone that is hinged; sexual dimorphism exists where males become much larger after reaching sexual maturity; overall dorsum coloration is variable either being a yellowish gray, pale blue, rust tan or pinkish orange cast; rowed dorsal diamond shaped blotches are dark with pale white borders lining the back; diamond blotches are often peppered with darker speckled scales; tail is white with jet black rings; head is distinctly patterned with an angled pale oblique band from nostril to upper labials; another thinner light colored stripe extends back and down forming a steep angle from posterior of eye towards end of mouth's supralabials; ventrum is off-white and usually unmarked by patterns; there are no considered subspecies.
Diet: Chief prey are small mammals such as rodents (mice, rats, voles, gophers, prairie dogs, squirrels, etc.) and rabbits & jackrabbits; birds are also taken including mockingbirds, quail & burrowing owls; along with other reptiles in particular lizards are also taken; juveniles prey on
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| 3. Opisthoglyphous fangs |
Habits: Outside of hibernating or mating, this is a solitary species; when threatened this snake will stand its ground; we like to anthropomorphize C. atrox by calling it ill tempered and savage, but in actuality it is simply defending itself from situations it perceives as life threatening; however, in the U.S. because of its defensive nature, more human fatalities each year are caused by C. atrox than any other snake; defensive posturing entails raising a third of anterior body with head directed at intruder while rattling tail; even though the snake cannot hear sound, it knows its adversaries can, so rattling is fair warning; can activate rattling up to 60 cycles/second; rattle warning may have evolved for the benefit of herding mammals, that could not see the camouflaged snake, but definitely could detect the rattle that it was nearby and not to tread too close; this saved the snake from being trampled and the mammal from being envenomated; venom evolved for acquiring prey and became secondary as a defense
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| 4. Defensive posturing |
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| 5. Two males battling |
Lizard species: P. cornutum- 1. Rune Midtgaard; 2. Tom Brennan; 3. Dr. Ted Macrini courtesy: Texas Memorial Museum; 4. A. E. Holte & M. A. Houck; 5. Tim Burkhardt. M. horridus 1. source: ianimal.ru (Russia); 2.&3. Dr. Jessie Maisano/Amy Balanoff courtesy: digimorph.org Univ. Texas; 4. Gerry Ellis; 5. Frans Lanting; 6. source: Wekipedia (German). P. apodus- courtesy: herpetofauna.at; 2. von Frank Burggraf; 3. Lukas Konecny; 4. illustrator J. Klembara (1981); 5. Jean-Pierre Vacher. H. horridus- Dr. Paddy Ryan; 2. Mark O'Shea; 3. illustrator S. B. McDowell; 4. Dr. Paddy Ryan; 5. Thomas Eimermacher; 6. source: Price Animal Company; 7. source: Zootropic/Nature Conservancy. S. crocodilurus- 1. Wilfried Berns; 2. source: leapinleachies.com (Leapin' Leachies); 3. Al Stotton; 4. source: tupian.hudong.com/wiki (China); 5. Ryan Hawk, courtesy: Woodland Park Zoo; C. lewisi- 1. source: wdict.net (German); 2. Matt Reinbold; 3. S. Cyd Read; 4. Dr. Paddy Ryan; 5. Luke (Wikipedia); 6. Tai Haku; 7. Mike Kern source: mkern/Images. P. kuhli- 1. source: reptilia.nl (Netherlands); 2. lft: E. Yakhontov, mdl: Tom McHugh, Rt: E. Yakhontov; 3. Herve Saint Dizier; 4. Peter Kollar; 5. Tom McHugh; 6. courtesy: Warren Photographics. P. laticeps- 1. Todd Pierson; 2. John Kenney; 3. Pierson Hill; 4. Laura Moyer; 5. Brent Steury; 6. Eric B. Holt. A. allisoni- 1. Todd Jackman; 2. Eladio Fernandez; 3. source: Wikimedia Commons; 4. Chris Miller; 5. Tom & Martina Trnka Dubois; 6. M. Butler, S. Sawyer & J. Losos. C. calyptratus- 1. Chris Kadet; 2. Professor Steve Huskey, Western Kentucky University; 3. William Warby; 4. source: generalexotics.com; 5. Gail J. Worth; 6. Donald Quintana; 7. hatchling: Michael D. Kern, neonate: J. Kleber, young juvenile: flchams.com. V. indicus- Peter Bonser; 3. Dr. S.P. Mackessy; 4. Lft: Kenneth Jensen, Rt: Joe Sablan; 5. Lft: source: Godzilla squatte la menagerie (France), Rt: Linda De Volder. C. collaris- 1.&2. Thomas C. Brennan; 3. William Wells; 4. Phil Myers; 5. William Wells.
SNAKES: 1. illustrator: Karen Carr; 2. Ramon Crater; 3. source: BBC News Online; 4. source: Journal of Vertebrate Paleontology; 5. sculptor: Tyler Keillor, photo: Ximena Erickson; 6. Zoltan Sylvester; 7. source: cbcreatures.webs.com (India); 8. Bruce A. Young (University of Massachusetts); 9. Sean Thomas; 10. arrangement: BJA.
Snake species: L. dulcis- 1. source: thehibbitts.net; 2. Jack Goldfarb; 3. Professor Nathan Kley, University of Stony Brook; 4. Sheryl Smith-Rodgers; 5. N.J. Kley & E.L. Brainerd (Nature 402: 11/25/1999). N. erythrogaster- 1. Will Bird, Ectotherms.net; 2. courtesy: SBS University of Texas Education; 3. J.D. Wilson; 4. courtesy: University of Texas at Dallas biology department; 5. Jeff LeClere (HerpNet.net). C. reinhardtii- 1. Eric Osterman 2. Daniel Heuclin; 3. Lft: Lubomir Klatil, Rt: Vladimir Moyycka; 4. Eric Osterman; 5. Lft: Rick Straub, Mid: Rick Staub, Rt: Tom Keogan. A. melanocephalus- 1. source: herpetobotanical.blogspot.com; 2. Paul Looyen; 3. Pilbara Pythons, Dave MacKintosh (Australia) 4. Lft: Stewart MacDonald, Mid: source: aussiepythons.com (Aspidito), Rt: Dave macKintosh; 5. Multipro Mining Operations staff, Stephen R. Dowling. C. hortulanus- 1. source: Science Photo Library; 2. source: charmthesnake.tmblr; 3. source: reptilis.org (France); 4. Peter Szymonik; 5. Vladimir Trailin; 6. Lft: Bill Love & Jerry Gingerich, Rt: Philippe Lesne`; 7. Lft & Rt: source: urbanjungles.com, Mid: source: coralluscaninus.info; 8. Lft: source: coralluscaninus.info, Mid: David Barkasy, Rt: source: urbanjungles.com; A. arafurae- 1. Rohan Clarke; 2. Matt Summerville; 3. Dayman Steptoe; 4. Dan Lynch. C. maculatus- 1. Fletcher & Baylis @ Visual Photos; 2. source: exploresrilanka.lk; 3. Chaminda Jayaratne; 4. Alex Pyron. B. subocularis- 1. Chris Newsom; 2. Lady Shmee; 3. Gary Nafis; 4. Lft; Gary Nafis, Mid & Rt: Troy Hibbitts; 5. oOBrieOo. C. palarostris- 1. Tom Brennan; 2. nmcrotalus source: flikr; 3. William T. Kendall; 4. Geoffrey Palmer. M. tener- 1. Matt Buckingham; 2. Craig Howard; 3.University of Sam Houston (Texas) Biological Dept.; 4. Jerry Cates; 5. Seth Patterson. B. dendrophilia- 1. source: divydovy.com; 2. source: Sir Mart Outdoorgraphy; 3. Dan Rosenberg (flikr); 4. Arie Lev; 5. Stuart Douglass; 6. source: reptiliaexpo.it (Italy). A. laevis- 1. Gary Bell; 2. Ross Gudgeon; 3. Cedric Mitel; 4. Veronique Lamare; 5. Mike Johns. B. insularis- 1. Rogerio Zacariotti; 2. source: ecoblogando.wordpress.com; 3. source: smarley.nl (Netherlands); 4. source: jureia.com.br (Brazil); 5. Otavio A. V. Marques. C. atrox- 1.William Wells; 2. Brian D. Hughes; 3. J.D. Wilson; 4. Brian D. Hughes; 5. Tim Allen.
Very thorough and reliable info! This page alone could be a book! Love your site!
ReplyDeleteThanks much anonymous for your reply and thought...I do hope awareness comes into play as well in that we share this world in living...
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