Snakes are elongated, legless, carnivorous reptiles that can be found on every continent except Antarctica. There are over 3,000 known species of snakes in the world, living in a wide variety of habitats from deserts to jungles to oceans. Determining exactly how many different types of snakes exist is tricky, as new species continue to be discovered every year. However, examining major snake families and genera can provide a good estimate of just how diverse and numerous these reptiles are globally.
Viperidae (Vipers)
The Viperidae family contains some of the world’s most infamous and recognizable snakes. This family includes rattlesnakes, copperheads, and other vipers known for their hinged fangs that inject venom. There are over 330 species of vipers around the world, spanning Asia, Europe, Africa, and the Americas. They occupy diverse habitats from swamps to mountains to grasslands. Some of the largest viper species can grow over 7 feet long.
Notable Viper Genera and Species:
- Rattlesnakes – Found in the Americas, over 30 species
- Puff Adders – Found in Africa, over 10 species
- Pit vipers – Found in Asia and the Americas, over 200 species
- Gaboon Viper – The heaviest viper in the world, found in Africa
- King Cobra – The world’s longest venomous snake, found in Asia
Colubridae (Colubrids)
The Colubridae is the largest snake family, containing over 700 different species. Colubrids are extremely diverse in appearance, behavior, habitat, and venom toxicity. Most species are nonvenomous and many primarily feed on rodents and other small prey. Colubrids are found on every continent except Antarctica and several species do well around human settlements. Notable colubrids include garter snakes, rat snakes, vine snakes, and racers.
Notable Colubrid Genera:
- Garter snakes – small, nonvenomous snakes found throughout North and South America
- Rat snakes – excellent climbers and rodent hunters found in Asia, Africa, and the Americas
- Kingsnakes – North American constrictors known for preying on other snakes
- Milk snakes – brightly colored American species once believed to milk cows
- Racers – speedy colubrids distributed across much of North America
Elapidae (Elapids)
The Elapidae family contains some of the most toxic snakes on Earth, including cobras, coral snakes, and sea snakes. There are over 300 species of elapids, characterized by their fixed front fangs and potent neurotoxic venom. While they have a worldwide distribution, elapids are most diverse in tropical regions like Australia and Southeast Asia. Notable elapids include the black mamba, coastal taipan, and inland taipan – considered the world’s most venomous snake.
Notable Elapid Genera:
- Cobras – Iconic hooded snakes found from Africa to Southeast Asia
- Mambas – Fast, arboreal, and highly venomous African snakes
- Kraits – Nocturnal, venomous snakes of South and Southeast Asia
- Coral snakes – Venomous American species with bright red, yellow, and black banding
- Sea snakes – Highly venomous marine snakes found in the Indian and Pacific Oceans
Pythonidae (Pythons)
Pythons are nonvenomous constrictors that are found in Africa, Asia, Australia and some Pacific islands. There are over 20 python species, including some of the largest snakes in the world like reticulated pythons and anacondas. On average pythons are not considered dangerous to humans, though larger individuals can inflict serious injuries through constriction. Pythons are ambush predators that have heat-sensing pits to detect warm-blooded prey.
Notable Python Species:
- Reticulated python – The longest snake in the world, native to Southeast Asia
- Burmese python – One of the five largest snakes, found in Asia
- Ball python – A smaller, more docile African species popular as pets
- Green tree python – An arboreal ambush hunter native to Australia and Asia
- Anaconda – The heaviest snake in the world, living in South America
Boidae (Boas)
Boids are nonvenomous constrictors like pythons that encompass around 70 species. They are found in the Americas, Africa, Europe, Asia, and some Pacific islands. Some of the largest boas include the green anaconda and reticulated python. Smaller, more docile species like the rosy boa are popular exotic pets. Boas use constriction to subdue prey and have heat-sensing pits on their faces like pythons.
Notable Boa Species:
- Green anaconda – The heaviest snake in the world
- Reticulated python – The longest snake in the world
- Rainbow boa – A slender, beautifully colored boa from Central and South America
- Rubber boa – A small species found across western North America
- Rosy boa – A docile, easy to handle pet species from the American southwest
Hydrophiinae (Sea Snakes)
Sea snakes are venomous elapids that have adapted to a fully marine lifestyle. There are over 60 species that inhabit warmer coastal waters from the Indian Ocean to the Pacific. They have paddle-shaped tails for swimming and valved nostrils to seal out water. Sea snake venom is potent, though most species are not aggressive. The yellow-bellied sea snake is one of the most widespread and frequently encountered species.
Notable Sea Snake Species:
- Yellow-bellied sea snake – Pelagic species found across the Pacific and Indian Oceans
- Beaked sea snake – A larger species up to 6 feet long found around Australia and Southeast Asia
- Olive sea snake – Generally avoids the surface and dives up to 100 meters deep
- Horned sea snake – Recognizable by spiny scales on its head, native to Australia
- Dubois’ sea snake – A critically endangered species limited to a small region of Indonesia
Atractaspididae (Burrowing Asps)
The Atractaspididae are a family of fossorial (burrowing) snakes found across much of Africa and the Middle East. There are around 90 species often called burrowing or mole vipers due to their underground habits. They have stout, spade-shaped heads used for tunneling through soil and unique hinged fangs. Venom toxicity varies between species – some being harmless to humans while others can inflict serious envenoming.
Notable Burrowing Asp Species:
- Mole viper – A small but dangerously venomous species found in sandy deserts of Namibia and Angola
- Stiletto snake – A common African burrower with less toxic venom than many other genera
- Rhinostoma – Unusual burrowers from Kenya and Somalia that feed primarily on amphibian eggs
- Parasphenoid snake – A poorly understood genus native to southern Africa
Leptotyphlopidae (Threadsnakes and Blindsnakes)
Threadsnakes and blindsnakes comprise over 100 species of tiny, primitive snakes. They are found across Africa, Asia, Australia, and the Americas. Most species look like shiny earthworms and measure less than 1 foot long. Threadsnakes are nonvenomous and fossorial, spending much of their time underground. Their eyes are vestigial and covered by large scales. Given their small size and secretive nature, threadsnakes are infrequently encountered and remain poorly understood by scientists.
Notable Threadsnake Genera:
- Leptotyphlops – The most widespread genus with over 40 species on three continents
- Rena – Small, colorful African blindsnakes
- Rhinoleptus – A poorly known Asian genus
- Epacrophis – Includes some of the only aquatic blindsnake species
- Myriopholis – Host to the world’s smallest snake, found in Barbados
Conclusion
In summary, there are over 3,000 snake species in the world divided among numerous families like vipers, constrictors, elapids, and sea snakes. While the true diversity is difficult to quantify, some of the most speciose genera include rattlesnakes, rat snakes, cobras, racers, garter snakes, and threadsnakes. Discovering and documenting new species remains an ongoing effort by herpetologists given the secretive nature of many snakes. Particular hotspots for snake diversity include the Amazon rainforest, Sub-Saharan Africa, and Southeast Asia. With their impressive adaptations, nearly global distribution, and range of habits, snakes occupy a number of vital ecological niches across land, sea, forests, and deserts.