Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes. Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads. To accommodate their narrow bodies, snakes' paired organs appear one in front of the other instead of side by side, and most have only one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca. Lizards have independently evolved elongate bodies without limbs or with greatly reduced limbs at least twenty-five times via convergent evolution, leading to many lineages of legless lizards. These resemble snakes, but several common groups of legless lizards have eyelids and external ears, which snakes lack, although this rule is not universal.
Elapidae is a family of snakes characterized by their permanently erect fangs at the front of the mouth. Most elapids are venomous, with the exception of the genus Emydocephalus. Many members of this family exhibit a threat display of rearing upwards while spreading out a neck flap. Elapids are endemic to tropical and subtropical regions around the world, with terrestrial forms in Asia, Australia, Africa, and the Americas and marine forms in the Pacific and Indian Oceans. Members of the family have a wide range of sizes, from the 18 cm (7.1 in) white-lipped snake to the 5.85 m king cobra. Most species have neurotoxic venom that is channeled by their hollow fangs, and some may contain other toxic components in various proportions. The family includes 55 genera with around 360 species and over 170 subspecies.
Rattlesnakes are venomous snakes that form the genera Crotalus and Sistrurus of the subfamily Crotalinae. All rattlesnakes are vipers. Rattlesnakes are predators that live in a wide array of habitats, hunting small animals such as birds and rodents.
Garter snake is the common name for small to medium-sized snakes belonging to the genus Thamnophis in the family Colubridae. Native to North and Central America, species in the genus Thamnophis can be found in all of the lower 48 United States, and nearly all of the Canadian provinces south of the Northwest Territories and Nunavut—with the exception of Newfoundland and Labrador. They are found from the subarctic plains of west-central Canada east through Ontario and Quebec; from the Maritime Provinces and south to Florida, across the southern and central U.S. into the arid regions of the southwest and Mexico, Guatemala and south to the neotropics and Costa Rica.
The common garter snake is a species of snake in the subfamily Natricinae of the family Colubridae. The species is indigenous to North America and found widely across the continent. There are several recognized subspecies. Most common garter snakes have a pattern of yellow stripes on a black, brown or green background, and their average total length is about 55 cm (22 in), with a maximum total length of about 137 cm (54 in). The average body mass is 150 g (5.3 oz). The common garter snake is the state reptile of Massachusetts.
The grass snake, sometimes called the ringed snake or water snake, is a Eurasian semi-aquatic non-venomous colubrid snake. It is often found near water and feeds almost exclusively on amphibians.
The tiger snake is a large and highly venomous snake of southern Australia, including its coastal islands and Tasmania. These snakes are often observed and locally well known by their banding, black and yellow like a tiger, although the species can be highly variable in coloration and patterning. All populations are classified within the genus Notechis (Elapidae). Their diverse characteristics have been classified either as distinct species or by subspecies and regional variation.
Natrix is a genus of Old World snakes found mainly across Eurasia in the subfamily Natricinae of the family Colubridae. They are commonly called grass snakes and water snakes, but some other snake species also known commonly as "grass snakes" and "water snakes" are not in the genus.
The Aesculapian snake is a species of nonvenomous snake native to Europe, a member of the Colubrinae subfamily of the family Colubridae. Growing up to 2 metres (6.6 ft) in length, it is among the largest European snakes, similar in size to the four-lined snake and the Montpellier snake. The Aesculapian snake has been of cultural and historical significance for its role in ancient Greek, Roman and Illyrian mythology and derived symbolism.
The desert monitor is a species of monitor lizard of the order Squamata found living throughout North Africa and Central and South Asia. The desert monitor is carnivorous, feeding on a wide range of vertebrates and invertebrates.
Diadophis punctatus, commonly known as the ring-necked snake or ringneck snake, is a rather small, harmless species of colubrid snake found throughout much of the United States, as well as south in Central Mexico and as far north as Quebec, Canada. Ring-necked snakes are generally fossorial and somewhat secretive, by nature, and, as a nocturnal species, are rarely seen during the daytime. These snakes are believed to be fairly abundant throughout most of their range, though no scientific evaluation supports this hypothesis. Scientific research is lacking for the species, despite their apparently common status, and more in-depth investigations are greatly needed. It is the only species within the genus Diadophis and, currently, 14 subspecies are identified, though many herpetologists question the morphologically-based classifications.
Nerodia rhombifer, commonly known as the diamondback water snake, is a species of nonvenomous natricine colubrid endemic to the central United States and northern Mexico. There are three recognized subspecies of N. rhombifer, including the nominotypical subspecies.
Nerodia erythrogaster, also known as the plain-bellied water snake or plainbelly water snake, is a common species of semi-aquatic, non-venomous colubrid snake endemic to the United States.
The banded water snake or southern water snake is a species of mostly aquatic, nonvenomous, colubrid snakes most commonly found in the Midwest, Southeastern United States.
Nerodia clarkii, commonly known as the salt marsh snake, is a species of semi-aquatic, nonvenomous, colubrid snake found in the southeastern United States. Their range extends along the brackish salt marshes of the Gulf of Mexico and the Atlantic Coast from Texas to Florida, with an additional population in northern Cuba. Different subspecies of this snake are primarily identified via color patterns on each snake's belly, or anterior.
Rhabdophis tigrinus, also known commonly as the tiger keelback, yamakagashi, or kkotbaem, is a species of venomous snake in the subfamily Natricinae of the family Colubridae. The species is native to East Asia and Southeast Asia. Many sources, though not ITIS, recognize one subspecies, Rhabdophis tigrinus formosanus of Taiwan.
The black-necked spitting cobra is a species of spitting cobra found mostly in sub-Saharan Africa. They are moderately sized snakes that can grow to a length of 1.2 to 2.2 m in length. Their coloration and markings can vary considerably. They prey primarily on small rodents. They possess medically significant venom, although the mortality rate for untreated bites on humans is relatively low. Like other spitting cobras, they can eject venom from their fangs when threatened. The neurotoxic venom irritates the skin, causing blisters and inflammation, and can cause permanent blindness if the venom makes contact with the eyes and is not washed off.
The common watersnake is a species of large, nonvenomous, common snake in the family Colubridae. The species is native to North America. It is frequently mistaken for the venomous cottonmouth.
Anchieta's cobra, sometimes referred to as the Angolan cobra, is a species of venomous snake in the family Elapidae. The species is native to Southern Africa.
Naja romani is an extinct species of cobra from the Miocene of Europe. Its remains have been found from France to Russia and suggest a continued growth to larger sizes throughout its range in time. While successful during the early and middle stages of the Miocene, the species disappeared from the fossil record of Central Europe during the late Miocene with the last known specimen being recovered from a site in the modern Caucasus, inferred to have been a refuge for reptiles. Estimates suggest that Naja romani may have reached a length of over 2 m.
