Snakes of the Americas

The Americas

The non-venomous snakes

American Blindsnakes:
The Americas have an abundant blindsnake assortment, the Anomalepididae being endemic to the area. While, the basal alethinphidians are weakly represented, only the ubiquitous but monotypic pipesnake genus, Anilius, inhabiting tropical South America. With four families represented: Leptotyphlopidae, Typhlopidae, Anomalepididae and Aniliidae.

These are the most widely distributed scolecophidians in the area with about 50 species in genus Leptotyphlops, including what is possibly the smallest snake in the world, L. bilineatus from the Lesser Antilles, which reaches a maximum adult length of 11cm. Several species are only known from a few specimens and over 30 species are single country endemics or known only from their restricted type localities. Although these tiny snakes are found in the Bahamas and Hispaniola they strangely appear not to be in Cuba, the biggest, and most herpetologically diverse West Indian Island.
The blindsnakes (Family Typhlophidae) include many small species similar in size to the slender blindsnakes but several larger, more robust species as well. The typhlophid blindsnakes are widespread in tropical South America and have a greater diversification in the Caribbean than the Leptotyphlopids they also inhabit Central America, but aren’t found further north than southeastern Mexico, implying that American species could be less acclimatized to desert habitats than the smaller lepyotyphlopids. There are around 25 country endemics amongst the 40 American species of Typhlops, several with very localized distribution.
The primitive blindsnakes (family Anomalepididae), occasionally referred to as ‘dawn blindsnakes, are closely related to the typhlopid blind snakes, from which they are thought to be an early offshoot, hence their common name. The 16 known species, in four genera, are endemic to Latin America, living in southeastern Brazil, the lower Amazon and Guianas, Trinidad, and the Choco region from northwestern Venezuela to lower Central America and coastal Ecuador. Distinct from the typhlopid blindsnakes, some species of early blindsnake have teeth on both upper and lower jaws, but this trait is not universal in this small family.
The most primitive American snake above the blindsnakes is the monotypic South American pipesnake (family Aniliidae), all other basal alethinophidian families are Southeast or South Asian in distribution. Its existence on the other side of the Pacific is intriguing, as it lives on the Atlantic side of South America.

American macrostomatan snakes:
The macrostomatans are the big mouthed snakes, meaning all snakes above the level of basal pipesnakes and their small mouthed relatives. Many American macrostomatans are boas, however the area is the habitat of one anomalous species occasionally referred to as a python, now believed to be more closely related to the sunbeam snakes of Asia.

Members of the Boidae, Tropidophiidae and Ungaliophidae within the Americas, are known as boas, including giant species like the anacondas and pint-sized species like the eyelash and dwarf boas. Some of the woodsnakes of genus Tropidophis areeasily confused with the more advanced colubrids. While true boas abound, there are no true pythons in America.
Earlier the Neotropical treeboas genus Corallus had only three species. Today eight species are accepted, from south eastern Brazil to Guatemala. Typical traits of the group include a strongly muscular body; long, prehensile tail; bulbous head, with long snout; big eyes, with vertically elliptical pupils; large and highly visible labial pits, and long curved teeth, particularly in the front of the jaws.
As a group, they possibly display more variation in color and pattern than any other genus of boas, even having variation in the same location or litter of neonates. Mainly arboreal, and living in rainforest or riverine forest habitats, but several species inhabit dry forests or the Brazilian savannah-woodland.
It might be thought that the arboreal treeboas prey on birds, but although they will take birds they are mainly nocturnal predators of small arboreal mammals and bats, the latter caught on wing. The existence of a large, extremely sensitive arrangement of heat-sensitive pits along both the upper and lower lip scales considerably boosts their ability to find and catch prey in the total dark of the rainforest night. Their big eyes, with sensitive retinas and vertically elliptical pupils, also help in making them outstanding hunters. The eyes of some, if not all, species of Corallus, have an ability not known for any other snakes: they reflect eye-shine.
Rainbow boas are the only mainland species of the large boa genus Epicrates, the other species being restricted to the West Indies. As a genus, Epicrates is quite varied, having species smaller than 1.0 metres to species longer than 4.0 metres. Mainland rainbows attain lengths around 2.0 metres. Although Caribbean species have quite limited distributions, rainbow boas are widespread through mainland Latin America. Typical traits that link the species of Epicrates, and make them different to other Neotropical boas, include having large regular scales on the top of the head, between and in front of the eyes, instead of the small granular boid scales. They are popularly kept in captivity.
West Indian Boas:
There are nine species of the genus Epicrates in the Caribbean, and only two species on the entire Latin American mainland. They vary in size from under 1.0 metres to over 4.0 metres and live throughout the West Indies, except the Lesser Antilles. The centers of evolution appear to be the Island of Hispaniola and the Bahamian Islands, with three species each, but they also live in Cuba, Jamaica, Puerto Rico and the Virgin Islands.
The genus Boa has a single Neotropical species, Boa constrictor. In 1991 the genus was widened to include the three Madagascan boas previously in the genera Acrantophis and Sanzinia, based on the scrutiny of 79 morphological traits. But, in 2001 this was reversed by a molecular study, which showed that, while Boas and Malagasy Boas have a strong similarity, Boa is genetically closer related to Epicrates and Eunectes, with which it forms a Neotropical genus, and to which the Madagascan Boas form a sister genus.
While the Reticulated Python, Python reticulatus from Southeast Asia is the longest snake in the world, when it comes to which species is the largest, other aspects need to be considered, like. girth and weight. Undoubtably, the widest, bulkiest and heaviest snake in the world is the Green -Anaconda, Eunectes murinus.
Anacondas can be described as large aquatic South American boas. The word ‘anaconda’ isn’t Spanish, or Portuguese, or even a native American name. ‘Anaconda’ is a Sinhalese word, coming from Sri Lanka, and meaning ‘python’. It’s a vernacular name for the Sri Lankan strain of the Indian Rock Python, Python molurus. The use of a Sinhalese word for python to an aquatic South American boa emulates the way the words ‘boa’ (a mythological child-eating, cattle-killing Italian snake) and tarantula’ (a large southern European wolf spider) were conveyed to the neotropics.
The path of these names is due to colonization. They were used by early travellers, explorers and settlers from Spain, Portugal and Italy who, visiting South America and finding large snakes and spiders, portrayeded them using familiar European names. In those days the Portuguese had many far-flung colonies, including the part of the Amazon that is now called Brazil, home of the anacondas, and Taprobane, an Indian Ocean island that under British control became Ceylon, now known as Sri Lanka. Apparentlyy the Sinhalese name for python was taken to the Americas by Portuguese sailors and settlers who had eheard the name used for large snakes in Taprobane.
There is not only one species of anaconda; five species have been described and currently four are be recognized. The Green Anaconda, E. murinus, was described by Linnaeus in 1758 as Boa murina over 100 years later Cope described a second smaller species from further south, the Yellow Anaconda, E. notaeus. In 1936 a strange and unlikely event occurred: two new species of anaconda were described from living specimens at the Philadelphia Zoo. Which itself was not strange, live specimens were used as type specimens in the past, though it is frowned on today, but the two new species were unusual because they were thought to have been gathered from the same place, a large island in the mouth of the Amazon, Ilha de Marajo in Para state. The Green Anaconda was already known for Amazonia, including Marajo, so the idea that two more species of anaconda might exist in the same location, in the same habitat, was incredible.
The two new species were Barbour’s Anaconda (E. barbouri), which looked like a Green Anaconda, and De Schauensee’s Anaconda (E. deschauenseei), named in honor of the collector of both specimens. This second species resemblanced the Yellow Anaconda from much further to the southwest. The status of Barbour’s Anaconda was challenged repeatedly in the following years and when specimens of Green Anaconda, from all over its extensive range, were discovered with barbouri-type patterning it was concluded that it was not a valid species and E. barbouri was placed within E. murinus. At this time, some disbelievers said that De Schauensee’s Anaconda was nothing more than a Yellow Anaconda.
But, the confinement of the two populations, with E. notaeus in southwestern Brazil and Paraguay, a region known as the Pantanal, and E. deschauenseei on Ilha de Marajo thousands of kilometres to the northeast, and its subsequent discovery in the extreme northeastern state of Amapa and nearby French Guiana, implied that, while the two species were very similar, they were most likely to be sister-taxa, separated by the Amazon-dwelling Green Anaconda, than two isolated populations of the same species.
Boas are not usually identified with North America but two species do inhabit the United States and one of these even spreads into Canada. Both species are small, enigmatic and semi-fossorial. Both species are popular in captivity. They are the sole New World examples of the Old World boid subfamily Erycinae, which includes the sand boas of Africa and Asia and the Calabar Ground Boa of West Africa. The taxonomy of this subfamily has experienced extensive alteration recently, including the recognition of a single genus, Charina, for the two American species and the Calabar Ground Boa.
With the elimination of the Central American dwarf boas from the Tropidophiidae, the genus Trachyboa, from Pacific northwest South America, is the sole genus, besides the West Indian-South American Tropidophis remaining in this small Neotropical family. These two species of eyelash boa are inadequately documented in the wild and are challenging to keep in captivity. The term ‘eyelash boas’ is inaccurate, because only one species has the enlarged horn-like scales over the eye which the common name comes from.
Three species of Central American dwarf boas, two bromeliad boas (also called banana or vine boas), in the genus Ungaliophis, and the monotypic Oaxaca Dwarf Boa, Exiliboa plicata, were earlier put in the family Tropidophiidae, with West Indian dwarf boas, however recent DNA analysis contends they should have their own family. They are small, enigmatic snakes whose distribution and natural history are inadequately documented.
The tiny West Indian snakes of the genus Tropidophis have been a protracted question for the taxonomist. Are they boas or colubrids? They may outwardly appear small semi-fossorial colubrids, but many species have vestigal pelvic girdles and the males have small but visible cloacal spurs, both well-known boid traits. The question was solved by placing them in their own family, the Tropidophiidae, which is enlarged to include the monotypic South American genus Trachyboa. The West Indian dwarf boas are also known as woodsnakes, due to their association with woodland habitats and their covert nature, hiding inside rotten logs and bromeliads. They have vertically elliptical pupils and prehensile tails. Currently 20 species are recognized, 17 from the Caribbean and three very inadequately documented species from remote locations in Ecuador, Peru and southeast Brazil. 13 of the 17 West Indian species are endemic to Cuba and its satellite islands; one is widespread in the Great Antilles (Cuba, Hispaniola and Jamaica); the Bahamas and the Cayman Islands are home to two and one endemic species respectively. Many are very small snakes with a size below 0.75metres, though one species reaches an impressive 1.0metres. Most species are inadequately documented with few specimens, natural history notes or field observations. Many of the island populations might be threatened by habitat loss and introduced domestic animals.

The Venomous Species

American Elapids:
The family that gives us the cobras and their relatives in Africa and Asia, the Taipans and Tigersnakes in Australia, the elapidae is represented by the coralsnakes in the Americas.

Coral snakes are not seasnakes, but are terrestrial snakes, their name derives from the bright coral-red bands that characterize most, not all, of the seventy plus species. Among American snakes, particularly the highly venomous coralsnakes and their mimics, red is not an unusual color but it is rare on other continents. Coral snakes live in every country in mainland American, with the exception of Canada and Chile, and some of the continental islands. They live in all habitats, swamps, rivers, woodlands, grasslands, even deserts, but the majority of species dwell in rainforests. They are not often encountered, because they are secretive, nocturnal snakes. They possess tiny eyes and are extremely venomous. But, they only account for 0.9% of serious snakebites in Latin America. Most of them belong to the large genus Micrurus but there is four species of slender coralsnakes and the Sonoran coralsnake, that are placed in two other genera. The coralsnakes of genus Micrurus may be separated into subgroups depending on the pattern of their red and black bands (white or yellow bands are absent in some species).
They have a single black band between each pair of red bands (red/yellow/black/yellow/red).
Have three black bands between each pair of red bands (red/black/yellow/black/yellow/black/red).

There are the ‘mimics’, nonvenomous or mildly venomous snakes, throughout the entire range of coralsnakes. The ‘false coralsnakes’. North American coralsnakes can be distinguished by the old rhyme “Red to Yellow, kill a fellow; red to black, venom lack”. By looking at the arrangement of the bands and deciding if the red bands contact the black bands or yellow bands it is possible to determine if the snake is a dangerous coralsnake or a harmless milksnake, in most instances. But, if you aren’t sure that it really is harmless, please let it be as this is not 100% guaranteed. In Latin America coralsnake patterns are far more varied, and there are many more ’mimics’ ranging from the red and black banded South American Pipesnake to some very elaborately patterned false coralsnakes the rhyme isn’t true, In fact in some areas of Latin America the coral snake and the false coralsnake have strikingly similar local variations in their patterning.

American Pitvipers:
There are no true vipers in America only pitvipers, that have heat-sensitive facial pits to help them hunt prey.

These pitvipers are most closely related to their ancestors that crossed the Bering land bridge from Asia 24 million years ago. When young all four species have bright yellow tail tips, which they twitch to lure prey within striking distance (caudal luring). As they get older the tip color fades. Their defensive behavior includes thrashing their tail in leaf litter to deter interference.

There are around 30 species of lanceheads that are found from Mexico to Argentina and on some islands. They are mainly terrestrial, but a few are semi-arboreal. These are widespread venomous snakes, extremely adaptable, moving into agricultural land or newly cleared habitats and producing high numbers of venomous babies. Their venom is cytotoxic and even surviving bites means suffering huge tissue damage leading to debilitating injuries or amputation. They are responsible for about 90% of all serious snakebites in Latin America.

Six species make up the South American genus Bothriopsis , which are considered part of the Lancehead group by some experts.

Most of the nine species in the Central American Genus, Bothriechis, have limited distribution, but several are more widespread.

Five new genera have been created or resurrected for these twenty five species previously considered part of the Lancehead group.

These really unique, huge, mainy nocturnal forest pitvipers are the longest pitvipers in the world, the only American pitvipers to lay eggs.
Bushmasters are seldom found in dry forest, needing annual rainfall of 2,000-6,000mm they are really rainforest snakes. Bushmasters dislike their habitat being disturbed. If rainforest is cleared and replaced with pastoral land or overgrown with secondary growth they quickly disappear and are substituted by the probably more dangerous Lanceheads. Statistics show that bushmasters are responsible for only 0.01% of all recorded bites in Latin American, they are greatly feared. A bite obtained in the jungle will almost assuredly be lethal and omitted from the statistics, because the victims might never reach the hospital. The Atlantic coastal bushmaster is threatened with extinction due to the clearing of its native habitat, the other species aren’t faring much better.
Bushmasters are exquisitely patterned with an array of dark diamond shaped markings over the center of their back, overlaying a yellowish or pinkish background. Each side of the dark diamond is centred with lighter color. They are stout bodied with a raised vertebral ridge and their head is rounded. Bushmasters do not chase people, but an irate adult will put on an impressive display, inflating its neck, raising its body, and vibrating its tail in the leaf litter. They lead a mainly sedentary life, lying motionless in ambush for days, staying in animal burrows for long periods, they can live for 30 years or more.

Evolving on the plains of North America they developed rattles, an excellent way to warn off a herd of heavy footed short sighted bison or potential predator. Of the 32 species of rattlesnake, all but two are in the genus Crotalus. They live in every mainland American country, except Panama, Ecuador and Chile, and a number of islands. Some are extremely rare like the Autlan rattlesnake (C. lannomi) which is known from a single specimen from Jalisco, Mexico.
South American Rattlesnakes consist of 11 subspecies, living east of the Andes.
Two small rattlesnakes making genus Sistrurus are different to the typical rattlesnakes of genus Crotalus due to the structure of the male’s hemipenes. They also have the enlarged regular head scutes more commonly associated with colubrids and elapids.

The Caribbean:
Hundreds of large and small islands, the West Indies is home to nearly 700 species of reptiles and amphibians, but dangerous venomous snakes are found on only a few of them. There are endemic venomous snakes on only five of the islands. Many islands off the north coast of South America are inhabited by South American Species.

South American Rear-fanged Colubrids:
It was thought, for many years, that only dangerous rear-fanged colubrids were African treesnakes but recently a number of serious snakebites have arisen from species thought harmless or inoffensive. These bites occurred mainly to herpetologists or herpetoculturists, rather than agricultural workers or villagers as is usual with viper and elapid bites. Probably because the bites frequently require some provocation and tend to happen when the snake is being caught or handled, rather than just encountered in the field. While serious effects are unusual, and deaths even rarer, it is imperative to be aware that no antivenom exists for the treatment of these bites, regardless of how serious they become.

North American Species

Family: Typhlopidae Blind snakes – 1 species
Brahminy Blindsnake Ramphotyphlops braminus *

Family: Boidae Boas – 5 species
Subfamily: Erycinae
Northern Rubber Boa Charina bottae
Rosy Boa Lichanura trivirgata
Northern Three-lined Boa Lichanura orcutti (formerly in L. trivirgata)
Southern Rubber Boa Charina umbratica
Subfamily: Boinae

Boa Constrictor Boa constrictor *

Family: Colubridae Colubrids – 125 species
Subfamily: Colubrinae

North American Racer Coluber constrictor
Sonoran Whipsnake Coluber bilineatus
Coachwhip Coluber flagellum
Baja California Coachwhip Coluber fuliginosus (formerly in Coluber flagellum)
Striped Racer Coluber lateralis
(Alameda Striped Racer C. l. euryxanthus: )
Striped Whipsnake Coluber taeniatus
Schott’s Whipsnake Coluber schotti (formerly in Coluber taeniatus)
Baja California Rat Snake Bogertophis rosaliae
Trans-Pecos Rat Snake Bogertophis subocularis
Pantherophis alleghaniensis
Texas Ratsnake Pantherophis obsoletus
Eastern Ratsnake Pantherophis alleghaniensis (formerly in Pantherophis obsoletus)
Gray Ratsnake Pantherophis spiloides (formerly in Pantherophis obsoletus)
Baird’s Ratsnake Pantherophis bairdi
Great Plains Ratsnake Pantherophis emoryi
Western Foxsnake Pantherophis ramspotti (formerly in Pantherophis vulpinus)
Eastern Foxsnake Pantherophis vulpinus
Red Cornsnake Pantherophis guttatus
Slowinski’s Cornsnake Pantherophis slowinskii (formerly in Pantherophis guttatus)
Glossy Snake Arizona elegans
Scarletsnake Cemophora coccinea
Variable Sandsnake Chilomeniscus stramineus (merged former C. cinctus, C. punctatissimus and C. stramineus)
Western Shovel-nosed Snake Chionactis occipitalis
Sonoran Shovel-nosed Snake Chionactis palarostris
Eastern Indigo Snake Drymarchon couperi
Central American Indigo Snake Drymarchon melanurus
Speckled Racer Drymobius margaritiferus
Tamaulipan Hook-nosed Snake Ficimia streckeri
Chihuahuan Hook-nosed Snake Gyalopion canum
Thornscrub Hook-nosed Snake Gyalopion quadrangulare
Gray-banded Kingsnake Lampropeltis alterna
Yellow-bellied Kingsnake Lampropeltis calligaster
Short-tailed Snake Lampropeltis extenuata
Common Kingsnake Lampropeltis getula
California Kingsnake Lampropeltis (getula) californiae
Speckled Kingsnake Lampropeltis (getula) holbrooki
Eastern Black Kingsnake Lampropeltis (getula) nigra
Desert Kingsnake Lampropeltis (getula) splendida
Sonoran Mountain Kingsnake Lampropeltis pyromelana
Knobloch’s Mountain Kingsnake Lampropeltis (pyromelana) knoblochi
Milksnake Lampropeltis triangulum
Scarlet Kingsnake Lampropeltis elapsoides (formerly in L. triangulum)
California Mountain Kingsnake Lampropeltis zonata
Rough Greensnake Opheodrys aestivus
Smooth Greensnake Opheodrys vernalis
Brown Vinesnake Oxybelis aeneus
Saddled Leaf-nosed Snake Phyllorhynchus browni
Spotted Leaf-nosed Snake Phyllorhynchus decurtatus
Gophersnake Pituophis catenifer
Pinesnake Pituophis melanoleucus
Louisiana Pinesnake Pituophis ruthveni
Pine Woods Littersnake Rhadinaea flavilata
Long-nosed Snake Rhinocheilus lecontei
Eastern Patch-nosed Snake Salvadora grahamiae
Western Patch-nosed Snake Salvadora hexalepis
Green Ratsnake Senticolis triaspis
Western Groundsnake Sonora semiannulata
Mexican Black-headed Snake Tantilla atriceps
Southeastern Crowned Snake Tantilla coronata
Trans-Pecos Black-headed Snake Tantilla cucullata (formerly in Tantilla rubra)
Flat-headed Snake Tantilla gracilis
Smith’s Black-headed Snake Tantilla hobartsmithi
Plains Black-headed Snake Tantilla nigriceps
Rim Rock Crowned Snake Tantilla oolitica
Western Black-headed Snake Tantilla planiceps
Florida Crowned Snake Tantilla relicta
Chihuahuan Black-headed Snake Tantilla wilcoxi
Yaqui Black-headed Snake Tantilla yaquia
Sonoran Lyresnake Trimorphodon lambda
California Lyresnake Trimorphodon lyrophanes
Texas Lyresnake Trimorphodon vilkinsonii (formerly in Trimorphodon biscutatus)
Subfamily: Natricinae

Kirtland’s Snake Clonophis kirtlandii
Saltmarsh Watersnake Nerodia clarkii
Gulf Saltmarsh Watersnake N. c. clarkii
Mangrove Saltmarsh Watersnake N. c. compressicauda
Atlantic Saltmarsh Watersnake N. c. taeniata :
Mississippi Green Watersnake Nerodia cyclopion
Plain-bellied Watersnake Nerodia erythrogaster
(Copper-bellied Watersnake N. e. neglecta:
Southern Watersnake Nerodia fasciata
Broad Banded Watersnake N. f. confluens
Banded Watersnake N. f. fasciata
Florida Watersnake N. f. pictiventris
Florida Green Watersnake Nerodia floridana
Brazos River Watersnake Nerodia harteri
Concho Watersnake Nerodia paucimaculata
Diamond-backed Watersnake Nerodia rhombifer
Northern Watersnake Nerodia sipedon
Brown Watersnake Nerodia taxispilota
Striped Crayfish Snake Regina alleni
Graham’s Crayfish Snake Regina grahamii
Glossy Crayfish Snake Regina rigida
Queensnake Regina septemvittata
Black Swampsnake Seminatrix pygaea
Dekay’s Brownsnake Storeria dekayi
Florida Brownsnake Storeria victa (formerly in Storeria dekayi)
Red-bellied Snake Storeria occipitomaculata
Aquatic Gartersnake Thamnophis atratus
Short-headed Gartersnake Thamnophis brachystoma
Butler’s Gartersnake Thamnophis butleri
Sierra Gartersnake Thamnophis couchii
Black-necked Gartersnake Thamnophis cyrtopsis
Terrestrial Gartersnake Thamnophis elegans
Mexican Gartersnake Thamnophis eques
Giant Gartersnake Thamnophis gigas
Two-striped Gartersnake Thamnophis hammondii
Checkered Gartersnake Thamnophis marcianus
Northwestern Gartersnake Thamnophis ordinoides
Western Ribbonsnake Thamnophis proximus
Plains Gartersnake Thamnophis radix
Narrow-headed Gartersnake Thamnophis rufipunctatus
Eastern Ribbonsnake Thamnophis sauritus
Common Gartersnake Thamnophis sirtalis
(San Francisco Gartersnake T. s. tetrataenia: )
Lined Snake Tropidoclonion lineatum
Rough Earthsnake Virginia striatula
Smooth Earthsnake Virginia valeriae
Subfamily: Dipsadinae

Forest Sharp-tailed Snake Contia longicaudae
Common Sharp-tailed Snake Contia tenuis
Desert Nightsnake Hypsiglena chlorophaea (formerly in Hypsiglena torquata )
Chihuahuan Nightsnake Hypsiglena jani (formerly in Hypsiglena torquata )
Coast Nightsnake Hypsiglena ochrorhyncha (formerly in Hypsiglena torquata )
Cat-eyed Snake Leptodeira septentrionalis (w/o former L. s. polysticta elevated now to species)
Subfamily: Xenodontinae
Eastern Worm Snake Carphophis amoenus
Western Worm Snake Carphophis vermis
Regal Black-striped Snake Coniophanes imperialis
Ring-necked Snake Diadophis punctatus
Red-bellied Mudsnake Farancia abacura
Rainbow Snake Farancia erytrogramma
Plains Hog-nosed Snake Heterodon nasicus
Dusty Hog-nosed Snake Heterodon gloydi (formerly in Heterodon nasicus)
Mexican Hog-nosed Snake Heterodon kennerlyi (formerly in Heterodon nasicus)
Eastern Hog-nosed Snake Heterodon platirhinos
Southern Hog-nosed Snake Heterodon simus

Family: Viperidae – 20 species
Subfamily: Crotalinae

Copperhead Agkistrodon contortrix
Cottonmouth Agkistrodon piscivorus
Eastern Diamond-backed Rattlesnake Crotalus adamanteus
Western Diamond-backed Rattlesnake Crotalus atrox
Sidewinder Crotalus cerastes
Timber Rattlesnake Crotalus horridus
Rock Rattlesnake Crotalus lepidus
Speckled Rattlesnake Crotalus mitchellii
Black-tailed Rattlesnake Crotalus molossus
Prairie Rattlesnake Crotalus viridis
Western Rattlesnake Crotalus oreganus (formerly in Crotalus viridis)
Arizona Black Rattlesnake Crotalus cerberus (formerly in Crotalus viridis)
Twin-spotted Rattlesnake Crotalus pricei
Red Diamond Rattlesnake Crotalus ruber
Mojave Rattlesnake Crotalus scutulatus
Panamint Rattlesnake Crotalus stephensae
Tiger Rattlesnake Crotalus tigris
Ridge-nosed Rattlesnake Crotalus willardi
(New Mexico Ridgenosed Rattlesnake C. w. obscurus’
Massasauga Sistrurus catenatus
Pigmy Rattlesnake Sistrurus miliarius

Family: Elapidae – 4 species

Sonoran Coralsnake Micruroides euryxanthus
Harlequin Coralsnake Micrurus fulvius
Texas Coralsnake Micrurus tener
Subfamily: Hydrophiinae

Yellow-bellied Seasnake Pelamis platurus
Family: Leptotyphlopidae Slender blind snakes – 3 species

Texas Threadsnake Leptotyphlops dulcis
New Mexico Threadsnake Leptotyphlops dissectus (formerly in Leptotyphlops dulcis)
Western Threadsnake Leptotyphlops humilis
Family: Acrochordidae File snakes – 1 species
Javanese File Snake Acrochordus javanicus *

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