Photos: What are vipers?

This photo post comes via Mongabay’s partnership with the Wildlife Conservation Society’s Wild View blog.
Under this partnership, we publish occasional original contributions from Wild View that highlights an animal species or group.
In this post, the Wildlife Conservation Society’s Herpetology Collection Manager Kevin Torregrosa writes about vipers.
Photos by WCS Staff Photographer Julie Larsen Maher.

Mangshan Pit Viper (Protobothrops mangshanensis). This newly-described large pit viper is found in the mountains of Hunan, China at high elevations. It is one of the few viper species that lays eggs. Photo by Julie Larsen Maher.

Puff Adder (Bitis arietans). This notorious African viper is often found in close proximity to humans. This leads to this snake having the dubious distinction of inflicting the most venomous snake bites of any species in South Africa. Photo by Julie Larsen Maher.

When many people think of snakes, they conjure up a vision of venomous serpents with huge fangs, large diamond-shaped heads, and cat-like eyes. The vision actually comes from the true-to-life physical appearance of vipers. This group of more than 300 species of snakes possess large heads that are distinct from the neck (diamond-shaped), the largest fangs of any of the venomous snakes, and elliptical pupils (cat-like). These characteristics may seem to play into an ophidiophobia nightmare, but in reality, they are important adaptations for this group of snakes’ place in their ecosystem. The shape of their head accommodates large venom glands used to incapacitate their prey. Their fangs are so large that they fold against the roof of their mouth when closed. These sizable fangs ensure that venom is delivered, and their food will not escape. Their elliptical pupils can dilate to allow more light in order to see better in the dark. Their features are perfectly designed for these ambush predators to lie in wait for the perfect opportunity to strike at unsuspecting prey animals.

Copperhead (Agkistrodon contortrix laticintus). Copperheads are found throughout the eastern US and parts of Northern Mexico. Copperhead venom is being used in research to fight cancer. Photo by Julie Larsen Maher.

Bushmaster (Lachesis muta). Native to Central and South American the bushmaster is the largest of the vipers. It is also the only viper in the Americas that lays eggs. This viper is part of the Species Survival Plan (SSP), a cooperatively managed program with the Association of Zoos and Aquariums (AZA) that oversees population management of select species with AZA member institutions like WCS’s Bronx Zoo. Photo by Julie Larsen Maher.

Eastern Diamondback Rattlesnake (Crotalus adamanteus). Found in the southeast US, this is the largest venomous snake in North America. Photo by Julie Larsen Maher.

Though all vipers share these features, this is a very diverse family of snakes. The family Viperidae consists of three subfamilies: Viperinae, Crotalinae, and Azemiopinae. The subfamily Viperinae comprises the true vipers and is represented by just more than 100 species. The true vipers are found throughout Europe, Africa, the Middle East, and Asia. One of the most iconic species in this group is the Gaboon viper from Africa. This viper holds the distinction of having the longest fangs of any snake at more than two inches in length. Crotalinae boasts the most species at more than 230. This subfamily, also known as the pit-vipers, is distinguished by the heat-detecting pit located between their eye and nostril. Found throughout the Americas and Asia, this group is also home to the rattlesnakes. The final subfamily, Azemiopinae, only contains two species; the Fea’s viper (Azemiops feae) and the white-head Burmese viper (Azemiops kharini) are both fossorial species from Southeast Asia. Among this family of snakes are the small Pygmy rattlesnake (Sistrurus milliarius) that is lucky to reach three feet as well as the bushmaster (Lachesis muta) which can reach lengths up to 10 feet.

Gaboon Viper (Bitis rhinoceros). This African species uses its geometric pattern to disappear amongst the leaves of the forest floor. At two inches in length, this snake possesses the longest fangs of any snake. Photo by Julie Larsen Maher.

Southwestern Speckled Rattlesnake (Crotalus pyrrhus). Found in the American southwest, this beautiful rattlesnake uses its color and pattern to perfectly blend into its surroundings. Photo by Julie Larsen Maher.

Variable Bush Viper (Atheris squamigera). This beautiful little viper from Africa lives up to its name. Its color is variable from uniform green, orange, yellow, black, or any combination of these colors. Photo by Julie Larsen Maher.

The bushmaster is unique in that it is the only New World viper to lay eggs. The majority of vipers break the traditional mold of reptiles in that they are ovoviviparous; their eggs hatch internally, and they give birth to live snakes. Vipers fill almost every niche in the ecosystem: they are arboreal and terrestrial and come from swamps and lakes as well as deserts. They can be found in the heat of the Sahara as well as the cooler temperatures of Europe and Canada.

The vipers’ adaptations for survival may have given rise to generations of people with an irrational fear of snakes, however; these snakes hold no ill will to humans. They simply want to do what they have done for the last 60 million years. They want to survive.

Aruba Island Rattlesnake (Crotalus durissus unicolor). This rattlesnake can only be found in small areas of desert habitat on the island of Aruba. It is among the rarest rattlesnakes in the world. This species is critically endangered, but recent education and public relations efforts through the SSP program have had a positive effect. Photo by Julie Larsen Maher.

Timber Rattlesnake (Crotalus horridus). Found in the eastern US from northern Florida all the way up to Canada, this species will congregate with dozens of other rattlesnakes as well as other reptiles in dens to survive the winter months. Photo by Julie Larsen Maher.

Santa Catalina Island Rattlesnake (Crotalus catalinensis). Only found on the island of Santa Catalina in the Gulf of California off the coast of Mexico, this species is known as the “rattleless rattlesnake” due to the fact that while it is born with the first button of a rattle it never adds to the rattle. It is listed as Critically Endangered. WCS’s Bronx Zoo is participating in a breeding program through the SSP. Photo by Julie Larsen Maher.

WCS Wild View posts related to vipers.

Correction (4/10/2019), the original version of this story placed Santa Catalina “off the coast of California” when in fact it is located in the Gulf of California. We regret the error.