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1, Introduction:

Lizard is a cold-blooded reptile, which is very similar to the early reptile ancestors that appeared in Triassic. Most of them reproduce by laying eggs, but some species have evolved to give birth to young lizards directly. Lizards usually have four feet, so they are also called "four-legged snakes". Lizards are the largest reptile family, with more than 4,700 recorded species and widely distributed habitats. Some of them live in the water, some live in the desert, some hide underground, some climb trees and even fly in the air. They will evolve into various forms because of different environments.

2. Main features

Lizard is the largest reptile group, with more than 4,000 known species in the world, mainly distributed in tropical areas. Body sizes vary greatly, from a few centimeters long Caribbean gecko to a nearly 3-meter-long Komodo dragon. Some species called snake lizards have degraded their feet, leaving only traces of their feet. They can be distinguished from snakes because they have eyelids and ears. Many lizards, such as chameleons, can change their colors to cope with environmental changes or stress.

Most species are carnivores, feeding on insects, earthworms, snails and even mice. However, some people take cactus or seaweed as their staple food, or are omnivorous. The general term for lizards and reptiles. Its close relatives, snakes, account for 95% of all living reptiles. * * * 18 family with more than 3000 species. Tropical areas have the largest variety and quantity. From the Arctic to South Africa, South America and Australia. Lizards are the most different in size and size among reptiles. Body length varies from 3cm (1 inch, gecko) to 3m (10ft, monitor lizard). The lightest is less than 1g, and the heaviest is more than 150kg. Slender body, long tail and developed limbs. In addition to the nostrils, mouth, eyes and cloaca openings, the body surface is covered with scales, a pair of eyes and a pair of ear holes. If there is no external auditory canal, the tympanic membrane is located on the surface, and some species have bone scales in the dermis under the scales of the head and body surface. The scales are covered with keratin.