This page focuses on the common European adder, Vipera berus, a small venomous viper found across much of Europe and northern Asia. Adders are shy snakes that usually avoid people. They warm themselves by basking, survive cold winters in sheltered hibernation sites, and give birth to live young instead of laying eggs.

Aldabra tortoises are giant land reptiles from the Aldabra Atoll in Seychelles. These slow, powerful grazers have huge domed shells, sturdy legs, long lifespans, and an important job shaping island vegetation.

Alligators are large reptiles with broad rounded snouts, armored skin, strong tails, short legs, and eyes on top of their heads. They live near water and are often confused with crocodiles, but they have their own alligator style.

The alligator snapping turtle is a giant freshwater reptile from the southeastern United States. This page focuses on Macrochelys temminckii, the species found mainly in the Mississippi River drainage, rather than the separately recognised Suwannee alligator snapping turtle. It spends most of its life underwater, where a worm-shaped lure on its tongue helps attract curious prey toward its enormous mouth.

The American alligator is a large armored reptile found in wetlands across the southeastern United States. Its broad rounded snout, dark colour, powerful tail, and mostly hidden lower teeth help distinguish it from the American crocodile. Alligators are major wetland predators, attentive mothers, noisy communicators, and ecosystem engineers that create watery refuges called gator holes.

The American crocodile is a large true crocodile that lives from southern Florida and Mexico through the Caribbean, Central America, and northern South America. It has a narrower, more pointed snout than the American alligator and often shows a large lower tooth even when its mouth is closed. Salt glands help it use coastal lagoons, mangroves, estuaries, and other brackish habitats, although young crocodiles still benefit greatly from freshwater.

Anacondas are giant nonvenomous snakes that live in or near water in warm parts of South America. They are powerful swimmers, heavy-bodied constrictors, and some of the largest snakes in the world.

Anoles are a remarkably diverse group of small and medium-sized lizards native to warmer parts of the Americas. Different species live on tree trunks, twigs, grass, rocks, and forest canopies. Many anoles have adhesive toe pads and a colourful throat fan called a dewlap, which they display with head bobs and push-ups. This page describes anoles as a group because their size, colour, diet, and behaviour vary greatly among hundreds of species.

Ball pythons are nonvenomous constrictor snakes from West and Central Africa. They are also called royal pythons, and their common name comes from their habit of curling into a tight ball when stressed or frightened.

Basilisk lizards are tropical reptiles from Central and South America, famous for sprinting across water when frightened. They live near streams and rivers, use strong back legs, and have special toe scales that help them dash over the surface for short distances.

Bearded dragons are spiky-looking lizards from Australia. They are famous for puffing out a throat pouch that looks like a beard, basking in warm sunlight, and using body signals such as head bobbing and arm waving.

Black mambas are long, fast, highly venomous snakes from parts of sub-Saharan Africa. They are not usually black on the outside; their name comes from the dark inside of the mouth, which they may show when threatened.

Blue-tongued skinks are chunky, smooth-scaled lizards known for their bright blue tongues. Many live in Australia and nearby regions, where they move along the ground, eat a mix of plants and small animals, and use their blue tongue to scare predators.

Boas are mostly nonvenomous constrictor snakes found in the Americas and some nearby regions. Boa constrictors and their relatives use strong muscles to hold prey, and many boas give birth to live young instead of laying eggs.

Boa constrictors are large, nonvenomous snakes from tropical parts of the Americas. They are famous for strong bodies, beautiful patterns, live birth, and a hunting method called constriction.

The Burmese python is a very large nonvenomous constrictor native to South and Southeast Asia. Its scientific name is Python bivittatus. Dark brown saddle-shaped blotches camouflage it among leaves, reeds, and swamp shadows. In its native range the species is Vulnerable because of habitat loss and heavy exploitation, yet escaped and released pets created a damaging invasive population in southern Florida.

Caimans are crocodilian reptiles from Central and South America. They belong to the alligator family, Alligatoridae, but they are not the same animals as the two living alligator species. The caiman group contains six living species, from the small Cuvier’s dwarf caiman to the enormous black caiman. Different caimans inhabit rivers, lakes, swamps, flooded forests, marshes, and mangroves, so size, snout shape, diet, and conservation needs vary across the group.

Chameleons are colorful lizards known for moving eyes, sticky tongues, grasping toes, and amazing color changes. Many live in trees and use careful slow movement to sneak through branches.

Chinese water dragons, also called Asian water dragons, are bright green lizards that live near forest streams and rivers in parts of Southeast Asia and southern China. They are strong climbers and swimmers with long tails, crests, and watchful eyes.

Cobra is a broad common name for several venomous snakes in the family Elapidae. Most true cobras belong to the genus Naja and live across Africa and Asia, while other hood-spreading snakes such as the king cobra and rinkhals belong to different genera. Cobras are famous for raising the front of the body and spreading a hood, but species differ greatly in size, colour, habitat, venom, diet, reproduction, and whether they can spray venom toward a threat.

The common snapping turtle, Chelydra serpentina, is a large freshwater turtle native to much of eastern North America. It has a rough brown or olive shell, an unusually long tail, a powerful beak-like jaw, and a flexible neck that can reach far beyond the front of its shell. Snapping turtles spend most of their lives in ponds, marshes, lakes, rivers, and slow streams, where they usually hide or swim away rather than confront danger.

Coral snakes are small, secretive venomous snakes with bright ringed patterns. They belong to the elapid family, the same broad snake family as cobras and sea snakes, and they are best watched from a safe distance.

Corn snakes are colorful nonvenomous snakes from the southeastern and central United States. They are helpful rodent hunters, use constriction to catch prey, and lay eggs in warm hidden places.

Crested geckos are small climbing lizards from New Caledonia. They are also called eyelash geckos because of the fringed crests above their eyes, and they move through rainforest branches using sticky toe pads and jumping skills.

Crocodiles are large reptiles with powerful jaws, sharp teeth, armored skin, long tails, and strong swimming skills. They live in warm places near rivers, wetlands, lakes, coasts, and mangroves.

The Eastern Brown Snake, Pseudonaja textilis, is a slender, highly venomous elapid native to eastern and central mainland Australia and southern New Guinea. It inhabits grassland, open woodland, farmland, scrub, and seasonal wetlands but generally avoids rainforest and alpine country. Adults vary from pale tan to dark brown or nearly black, while young snakes may have a black head patch and body bands. Eastern Brown Snakes are important rodent hunters and usually try to escape before defending themselves.

Frilled lizards are reptiles from northern Australia and southern New Guinea. They are famous for a large folded skin frill around the neck that can open wide when the lizard feels threatened.

Galápagos tortoises are giant land turtles from the Galápagos Islands of Ecuador. They are famous for enormous shells, slow movement, plant-eating diets, long lives, and an important conservation story.

Garter snakes are small to medium snakes famous for long stripes and backyard sightings. They are common in many parts of North America, often live near water or gardens, and help eat worms, slugs, insects, frogs, and other small animals.

Geckos are small lizards with soft skin, big eyes, quick movements, and amazing climbing feet. Many geckos are active at night and can climb walls or ceilings using special toe pads.

The gharial, Gavialis gangeticus, is a long-snouted crocodilian of large rivers in the northern Indian subcontinent. It belongs to the family Gavialidae and is one of the most aquatic living crocodilians. Adults have narrow jaws lined with many interlocking teeth, raised eyes and nostrils, short legs, webbed hind feet, and a powerful flattened tail. Mature males develop a bulbous growth called a ghara at the snout tip. Gharials feed mainly on fish and are globally Critically Endangered.

Gila monsters are colorful venomous lizards from the southwestern United States and northern Mexico. They are slow-moving reptiles with beadlike scales, black and pink or orange patterns, strong jaws, and fat-storing tails.

Glass lizards are long, mostly legless lizards in the anguid subfamily Anguinae. The name is used especially for species in Ophisaurus of North America, Pseudopus of Europe and western Asia, Dopasia of Asia, and Hyalosaurus of North Africa. They resemble snakes but have movable eyelids, visible ear openings, stiff armored skin, and long fragile tails. Most hunt insects and other small animals in grassland, woodland, dunes, scrub, farms, and rocky habitats. The tail can break into several wriggling pieces, giving the group its glass-like name.

Grass snake is a common name used for several closely related nonvenomous European snakes in the genus Natrix. This page focuses on the Common Grass Snake, Natrix natrix; the Barred Grass Snake, Natrix helvetica; and the Red-Eyed or Iberian Grass Snake, Natrix astreptophora. They live around ponds, rivers, marshes, meadows, woodland edges, gardens, and farms across Europe and into western Asia and northwestern Africa. Grass snakes are strong swimmers that mainly hunt frogs, toads, newts, and other small animals.

Green anacondas are giant nonvenomous snakes from South America. They spend lots of time in or near water, where their heavy bodies, swimming skills, and eyes near the top of the head help them hide and hunt.

Green iguanas are large tree-climbing lizards from tropical parts of Central and South America. They eat mostly leaves, flowers, and fruit, use long tails for balance and defense, and often rest high in trees near water.

Green sea turtles are large hard-shelled sea turtles that live in warm ocean waters. Adults mostly eat seagrass and algae, and females return to sandy beaches to lay eggs.

Hawksbill sea turtles are beautiful reef turtles with pointed beak-like mouths and patterned shells. They live in warm oceans, help coral reefs by eating sponges, and are critically endangered, so protecting beaches and reefs matters.

Horned lizards are small, flat, spiky reptiles from North and Central America. They are sometimes called horned toads, but they are lizards, not toads, and many are famous for eating ants, hiding in desert colors, and using strange defense tricks.

Iguanas are large lizards with long tails, scaly skin, strong claws, and spiky crests. Many iguanas live in warm places, climb trees, bask in sunlight, and eat mostly leaves, flowers, and fruit.

The Indian Cobra, Naja naja, is a dangerously venomous true cobra of the Indian subcontinent. It is also called the Spectacled Cobra because many individuals carry a double eye-like mark on the back of the expanded hood. Color and hood patterns vary widely, and some cobras lack a clear spectacle. Indian Cobras live in farmland, scrub, forest edges, wetlands, rocky areas, villages, and cities, often where rodents and shelter are available. They usually avoid people but may raise the front body, spread the hood, hiss, and strike when trapped or threatened.

The Indian Rock Python, Python molurus, is a very large nonvenomous snake native to the Indian subcontinent and Sri Lanka. It is a separate species from the darker Burmese Python, Python bivittatus, which older books sometimes treated as its subspecies. Indian Rock Pythons have pale tan, gray, yellowish, or brown bodies covered with dark irregular blotches, heat-sensitive pits along the lips, powerful muscles, and flexible jaws. They live in forest, scrub, grassland, rocky foothills, marshes, river valleys, and other habitats with reliable water and shelter.

King cobras are large venomous snakes from forests and wild areas of South and Southeast Asia. They are famous for their hood, long body, deep warning hiss, and unusual habit of eating other snakes.

King snake, usually written kingsnake in animal common names, refers to many nonvenomous New World snakes in the genus Lampropeltis. The genus currently contains 28 recognised species in the Reptile Database, although some are commonly called milk snakes rather than kingsnakes. These snakes range from southern Canada through the United States and Mexico into Central America and northwestern South America. They have smooth glossy scales and patterns that may be banded, ringed, striped, blotched, speckled, or nearly plain. Kingsnakes subdue many prey animals by constriction and are famous for eating other snakes, including some venomous species. Exact colour, size, habitat, diet, reproduction, venom resistance, and conservation status differ across the group.

Komodo dragons are giant monitor lizards from Indonesia. They are the largest living lizards, with strong bodies, sharp claws, forked tongues, tough skin, and powerful hunting skills.

Leatherback sea turtles are the largest sea turtles and the only sea turtles without a hard shell. They have a flexible leathery carapace, huge front flippers, and travel across oceans to find jellyfish and nesting beaches.

The Leatherback Turtle, Dermochelys coriacea, is the world's largest living turtle and the only surviving sea turtle without a hard, scaly shell. Its streamlined black body is covered by tough rubbery skin over thousands of tiny bones, with seven long ridges running down the back. Leatherbacks cross the Atlantic, Pacific, and Indian oceans, dive deeper than any other turtle, and travel between tropical nesting beaches and cold jellyfish-rich feeding seas. The species is globally Vulnerable, while several regional populations are Endangered or Critically Endangered.

Leopard geckos are small spotted lizards from dry rocky places in parts of Asia. Unlike many geckos, they have movable eyelids, clawed toes instead of sticky pads, and thick tails that store fat for lean times.

Lizard is the common name for more than 7,000 living squamate reptiles that are not usually called snakes or worm lizards. It is a useful everyday group but not one tidy evolutionary branch, because snakes evolved from within the broader lizard family tree. Lizards range from tiny island chameleons and geckos to the huge Komodo Dragon. Most have four legs, movable eyelids, external ear openings, dry scales, and long tails, but many species break one or more of those rules. They live on every continent except Antarctica.

Loggerhead sea turtles are ocean reptiles named for their large heads and strong jaws. They use those jaws to crush hard-shelled prey such as whelks, conchs, crabs, and other seafloor animals.

Mambas are fast, slender, venomous snakes from Africa. Some mambas live mostly in trees, while the black mamba often moves on the ground. They are amazing reptiles, but they should always be watched from far away and never touched.

Marine iguanas are unusual reptiles from the Galapagos Islands. They are the only modern lizards that regularly forage in the sea, where they swim and dive to eat algae growing on rocks.

Matamata turtles are strange-looking freshwater reptiles from northern South America. Their flattened heads, ragged skin flaps, rough shells, and long snorkel-like snouts make them resemble soggy leaves and bark on a muddy river bottom. Scientists now recognize two living species: the Amazon matamata, Chelus fimbriata, and the Orinoco matamata, Chelus orinocensis. Both are ambush predators that gulp prey using powerful suction.

Milk snakes are colorful nonvenomous snakes related to kingsnakes. Their red, black, white, yellow, or tan bands can make them look like coral snakes, but milk snakes are harmless to people when left alone and are helpful rodent hunters.

Monitor lizards are smart, active reptiles with long bodies, strong claws, powerful tails, and forked tongues. Different species live in Africa, Asia, Australia, and nearby islands, from forests and deserts to rivers and mangroves.

The monocled cobra is a highly venomous snake from South and Southeast Asia. Its scientific name is Naja kaouthia, and its famous hood often carries a single round mark that looks like an old-fashioned monocle. This cobra is impressive, but it must always be admired from a safe distance.

The mugger crocodile is a broad-snouted reptile of southern Asia. Its scientific name is Crocodylus palustris, and it is also called the marsh crocodile. Muggers are powerful freshwater predators, attentive parents, and surprisingly capable travelers on land—but they must always be observed from a safe distance.

The mulga snake is a large, powerfully built venomous snake found across most of Australia. Its scientific name is Pseudechis australis. It is often called the king brown snake, but that name is misleading: it belongs to Australia's black-snake genus, not the true brown-snake genus.

Pythons are nonvenomous snakes with long muscular bodies, flexible jaws, smooth scales, and strong squeezing power. They live in warm habitats and are famous for being constrictors, which means they wrap around prey instead of using venom.

Rattlesnakes are venomous snakes from the Americas, famous for the rattle at the end of the tail. They use camouflage, heat-sensing pits, fangs, and warning rattles to survive in deserts, grasslands, forests, and rocky places.

Reticulated pythons are huge nonvenomous snakes from South and Southeast Asia. They are famous for their net-like pattern, strong constriction, excellent swimming, and record-breaking length, but wild pythons should always be watched from a safe distance.

The saltwater crocodile, Crocodylus porosus, is the largest living reptile. It inhabits rivers, wetlands, mangroves, estuaries, coasts, and nearby seas from South Asia through Southeast Asia to northern Australia and western Pacific islands. This powerful ambush predator can tolerate salt water, cross long ocean distances, and disappear almost completely beneath a shallow surface.

Sea kraits are venomous sea snakes that split life between ocean and land. They hunt in coral reefs and coastal waters, but unlike fully ocean-living sea snakes, sea kraits return to land to rest, digest food, shed skin, mate, and lay eggs.

Sea snakes are marine reptiles that live in warm ocean waters. They are related to cobras, have venom, breathe air at the surface, and many have flattened paddle-like tails that help them swim through reefs, lagoons, and coastal seas.

Sea turtles are ocean reptiles with shells, flippers, lungs, and long life cycles. They live in the world’s oceans and come onto beaches to lay eggs in sandy nests.

Skinks are lizards in the enormous family Scincidae, which contains more than 1,500 living species. Many have shiny overlapping scales, long cylindrical bodies, small legs, and a barely visible neck, but the family also includes sturdy blue-tongued skinks, spiny crocodile skinks, burrowers with reduced limbs, and completely legless species.

The slow worm, Anguis fragilis, is neither a worm nor a snake. It is a harmless legless lizard with smooth shiny scales, blinking eyelids, a slightly notched tongue, and the ability to shed its tail. Slow worms spend much of life hidden in grass, soil, compost, leaf litter, or beneath sun-warmed objects while hunting slugs and other invertebrates.

Snakes are elongated legless reptiles in the group Serpentes. More than 4,000 living species occupy forests, deserts, grasslands, farms, caves, rivers, oceans, and cities on every continent except Antarctica. All are carnivores, but most are nonvenomous and avoid people while helping food webs by hunting rodents and other animals.

Snapping turtles are freshwater turtles named for their powerful biting defense. They have strong jaws, rugged shells, long tails, and a mostly aquatic life in ponds, lakes, rivers, swamps, and slow waterways.

What exactly is a terrapin? The answer depends on where you live. In Britain and some other places, people use the word for various freshwater or semi-aquatic turtles. In North America, “terrapin” usually means the diamondback terrapin, a special turtle of brackish coastal marshes. All terrapins are turtles, but terrapin is not one precise scientific group.

Thorny devils are small spiky lizards from dry parts of Australia. They look fierce with thorny bodies and a pretend head, but they are slow, harmless reptiles that mostly eat ants.

Tortoises are land-living turtles with sturdy legs, strong shells, and slow steady movement. They belong to the turtle order, but most tortoises spend their lives on land instead of swimming in water.

Tuataras are rare lizard-like reptiles from New Zealand, but they are not lizards. They are the only living members of an ancient reptile group and have spiky crests, a beak-like mouth, slow growth, and a hidden third eye on top of the head.

Turtles have traveled Earth for more than 200 million years. Their order includes sea turtles, freshwater turtles, terrapins, box turtles, and tortoises. From a tiny bog turtle to a giant leatherback, every species carries a remarkable shell that is built into its skeleton.

Vipers are venomous snakes known for long hinged fangs that fold back when not in use. This group includes many famous snakes, such as adders, rattlesnakes, copperheads, puff adders, and other vipers from many habitats around the world.