A lizard is any of over 5,500 species of reptiles in the suborder Sauria, order Squamata. Lizards have legs, movable eyelids, and external ear openings, but some species lack one or more of these features. They are diverse in body shape and size, ranging from 2 cm to 3 meters in length, and from less than 0.5 gram to more than 150 kg in weight. Lizards inhabit warm regions, with some near the Arctic Circle and others at the tip of South America. They occupy diverse habitats from underground to elevated vegetation. Most lizards are active during the day and eat insects, though some eat small vertebrates or plants. Lizards employ defensive strategies against predators such as remaining near rocks, displaying intimidating frills, or detaching their tails.

How are lizards different from other reptiles?

Lizards are reptiles belonging to the suborder Sauria in the order Squamata. Possessing legs, movable eyelids, and external ear openings usually distinguish them from snakes. However, some lizards lack one or more of these features. Lizards are the most diverse group of modern reptiles in body shape and size, ranging from 2 cm to 3 meters in length. Key distinctions between lizards and other reptiles: * Scales Except for a few openings, scales completely cover most lizards. * Habitat Lizards occupy diverse habitats, from underground burrows to elevated vegetation. * Limbs Most lizards are quadrupedal with powerful limb musculature, though some species are limbless. * Color Change Many lizards can change color due to pigment cells called melanophores. * Prehension Lizards use either lingual prehension (tongue) or jaw prehension to capture their prey.

Where do lizards usually live?

Lizards can be found in diverse habitats, from underground burrows to elevated vegetation. They occupy a variety of environments, including forests, grasslands, and deserts. Some lizards have adapted to extreme environments, such as deserts and oceanic islands, due to their ability to conserve water. In deserts of Australia, numerous lizard species coexist by separating themselves along niche axes, such as time, food, and place.

Lizards exhibit diverse feeding habits. Most lizard species consume insects, but some eat other animals, such as mollusks, birds, frogs, mammals, and even other reptiles. Some lizards are herbivorous, like the green iguana , chuckwalla , and spiny-tailed agamid . The marine iguana is unique because it dives into the sea for seaweed. Iguanian lizards are "sit-and-wait" predators that use visual cues to detect prey, while autarchoglossan lizards actively search for prey using their chemosensory system and visual cues.

How do lizards protect themselves from predators?

Lizards use various strategies to protect themselves from predators. When threatened, chuckwallas wedge themselves into rock crevices and inflate their bodies, making it difficult for predators to remove them. Similarly, spiny-tailed lizards move into crevices, exposing only their sharp tails. Some lizards, like the African armadillo lizard, curl into a spiny ball by holding their tail in their mouth, which prevents predators from finding a starting point to swallow them. Frilled lizards can extend a large neck frill to intimidate intruders. Many lizards can detach their tails (autotomize); the detached tail wriggles, distracting the predator while the lizard escapes. Coloration and patterns also play a role, with some lizards using camouflage to blend into their surroundings.

How do lizards help balance their ecosystems?

Lizards contribute to the balance of their ecosystems in various ways. Many lizard species eat large numbers of insects and other invertebrates, especially in deserts and tropical areas, which helps control pest populations. Some lizards also serve as a food source for larger animals, while others, like the Galapagos tortoise and iguanas, play a role in seed dispersal by consuming fruits and scattering the seeds. Additionally, lizards are models for studying competition between species and evolutionary biology.

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Images & Videos

Illustration showing ten types of lizards and related reptiles, each labeled with their common and scientific names, including Jackson's chameleon, plumed basilisk, flying lizard, red worm lizard, common wall lizard, eastern glass lizard, Texas horned lizard, tokay gecko, gila monster, and Algerian cylindrical skink.

Illustration showing specialized structures in lizards: the frilled lizard with its large neck frill extended, an anole displaying its red throat dewlap, a water lizard's dorsal sail, the fan-shaped toes of a fan-footed gecko, and the fringed toes of a fringe-toed lizard.

Unique traits of the Galapagos marine iguana

A Gila monster (Heloderma suspectum) with a patterned black and pink body rests on sandy ground among prickly pear cactus pads.

A bright green day gecko with red spots on its back rests on a branch, surrounded by dry leaves in Madagascar.

Emoia caeruleocauda, the Pacific bluetail skink, with a bright blue tail and striped body, stands on a piece of dark wood with blurred mushrooms in the background.

A diagram shows a terrestrial reptile on rocks, illustrating energy exchanges with the environment through arrows labeled for reflected radiation, evaporation, direct solar radiation, thermal reradiation, convection, and conduction of heat between the lizard and the rock. Environmental and body temperatures are also noted.

Red-barred dragon lizard, Ctenophorus vadnappa, rests on a rock with its tail curled, showing textured brown skin and orange markings, in the Flinders Ranges, Australia.

At a Glance

lizard summary

lizard

reptile

Also known as: Sauria

Written by

Laurie VittAll

Fact-checked by

Britannica Editors

Last updated

Nov. 12, 2026 •History

News •

Male lizard 'perfumes' may be more about rivalry than seduction • Nov. 9, 2026, 5:40 PM ET (Phys.org)

Lizard tail trapped in amber reveals a 99-million-year-old survival trick • Oct. 31, 2026, 7:35 AM ET (Earth.com)

Lizard Dropped Its Tail 99 Million Years Ago, Amber Preserved Evidence • Oct. 16, 2026, 3:00 AM ET (Sci.News)

lizard, (suborder Sauria), any of more than 5,500 species of reptiles belonging in the order Squamata (which also includes snakes, suborder Serpentes). Lizards are scaly-skinned reptiles that are usually distinguished from snakes by the possession of legs, movable eyelids, and external ear openings. However, some traditional (that is, non-snake) lizards lack one or more of these features. For example, limb degeneration and loss has occurred in glass lizards (Ophisaurus) and other lizard groups. Movable eyelids have been lost in some geckos, skinks, and night lizards. External ear openings have disappeared in some species in the genera Holbrookia and Cophosaurus. Most of the living species of lizards inhabit warm regions, but some are found near the Arctic Circle in Eurasia and others range to the southern tip of South America.

Snakes arose from lizards and are thus considered to be a highly specialized group of limbless lizards. In addition to those traits they have in common with non-snake lizards, snakes are often separated from other lizards in popular literature because they share a set of unique traits that are relatively easy to observe. For a full description of snakes, see snake.

General features

Lizards are by far the most diverse group of modern reptiles in body shape and size. They range from 2 cm (0.8 inch) snout to vent in geckos (family Gekkonidae) to 3 metres (10 feet) in total length in monitor lizards (family Varanidae). The weight of adult lizards ranges from less than 0.5 gram (0.02 ounce) to more than 150 kg (330 pounds). The popular conception of a lizard as a scampering reptile about 30 cm (12 inches) in total length with a slender tail may be applied accurately only to a small number of species. Representatives of several families are limbless and resemble snakes, whereas others have long hind legs that permit bipedal locomotion. Male lizards may be outfitted with a wide array of ornamentation—such as extensible throat fans and frills, throat spines, horns or casques on the head, and tail crests.

Lizards occupy diverse habitats that range from underground warrens and burrows to the surface and elevated vegetation. Some move slowly and rely on cryptic coloration for protection, whereas others can run swiftly across desert sands. Lizards of the family Mosasauridae, an extinct group, were strictly marine. Some mosasaurs were giants and grew to lengths of 10 metres (33 feet). One living lizard, the marine iguana (Amblyrhynchus cristatus) of the Galapagos Islands, feeds on algae in the sea. However, it spends much of its time basking on lava rocks on the islands. No other extant lizard species is marine, but several are partially aquatic and feed on freshwater organisms.

The role lizards play in human ecology is poorly known. Some lizards are sources of food and clothing or agents of pest control, whereas others are pests. Some larger lizards (such as the iguanas [Iguana and Ctenosaura] of Mexico, Central America, and South America) are eaten and are an important food source. Others are used for leather goods. Monitor lizards and tegus (family Teiidae) are harvested for their skins, and these skins have a major effect on local economies of rural areas in Third World countries. Although lizards are often portrayed as insectivores, many also consume small vertebrates and at least some plant material; strict herbivory has evolved independently in several groups of lizards. Nevertheless, lizards eat large numbers of insects and other invertebrates, particularly in the tropics and in deserts. These insect-control services affect humans in many subtle ways; however, such effects have not been well studied. Large predatory lizards (such as monitors and tegus) can be pests—often preying on farm animals or stealing chicken eggs—that affect the livelihoods of ranchers and farmers.

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Some relatively small lizard species, such as geckos, have not only colonized many islands by rafting with humans on boats but have also invaded cities and towns throughout the world. For example, throughout Brazil, one of the best-known lizards, the Mediterranean gecko (Hemidactylus mabouia), is so common in houses and buildings that most Brazilians know more about it, based on their own observations, than they know about any of the endemic species. As is the case with many introduced lizards, the Mediterranean gecko appears to do very well living with people in disturbed areas but does not seem to invade undisturbed habitats.

For the most part, lizards are not disease vectors and pose little danger to humans who take proper precautions when handling them. Lizards are often infected with various parasites, including a type of malaria, but these parasites tend to be species specific. Salmonella bacteria may be transmitted from a lizard to a human, particularly if the lizard is placed in a person’s mouth. Tuberculosis (Mycobacterium tuberculosis) and some viral and fungal infections may also pass from lizard to human. Persons handling lizards are advised to practice good personal hygiene.

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Only two species, the Gila monster (Heloderma suspectum) of the southwestern United States and northwestern Mexico and the Mexican beaded lizard (H. horridum) of western Mexico, are venomous. Both species bite humans only when provoked, and fatalities are very rare. Among the most harmless of lizards are geckos, which are falsely believed to be highly venomous by many indigenous cultures throughout the world. Reasons for this suspicion are unclear; however, the geckos’ nocturnal activity, elliptical pupils, and ability to walk up smooth vertical surfaces could make them seem supernatural to some cultures.

Lizards are also valued as subjects for biological research. Their varied modes of reproduction and their ability to regulate body temperatures are two of many areas studied by comparative physiologists (see thermoregulation). The great abundance and observability of numerous species make them ideal subjects for ecologists and ethologists. The ability of some species to regenerate broken tails has led to their use as research subjects by behavioral ecologists and developmental biologists. Since they are relatively clean and easy to keep, lizards are also quite popular as house pets.

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