Lizards are the general name 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, and some species have bone scales in the dermis under the scales of the head and body surface. The scales are covered with keratin. Some lizards have scaly organs, and the serrated edges of scales protrude bristles, which may be used for touch. Many lizards, especially chameleons and comfort lizards, can change their body color, from bright green to dark chocolate brown, and their lines and stripes can also flicker. The mechanism of discoloration is the movement of pigment particles in melanocytes, which is lighter when concentrated and darker when dispersed. Some lizards have extensible skin folds on their necks, horns or helmets on their heads and thorns or folds in their throats. The front of the skull consists of thin cartilage and membrane. The eyelids are movable, and the space between the eyes is a thin vertical orbital space. There is a temporal foramen on the backbone formed by the posterior orbital bone and squamous bone. The upper jaw can move relative to the rest of the skull, with a square bone and an open mouth for swallowing prey.

Most lizards feed on insects and some rodents, and occasionally eat poultry. Their teeth are sharp and have three sharp points. Herbivores (such as iguanas) have a broad leaflike crown with jagged edges. Feeding on molluscs and crustaceans (e.g. [Dracaena Dracaena]) has blunt teeth at the back of the upper jaw, which are used for crushing. The Gila monster in the southwestern United States and its Mexican relative (Heloderma) are poisonous. They bite when provoked, but they are rarely fatal. There are longitudinal grooves or folds on the inside of each tooth in the lower jaw, which are used to extract venom. Most lizard teeth are born on the edge of maxilla, anterior palatine bone and dental bone, and a few species are born on the palate. There are "egg teeth" on the palatine bone in embryonic stage, which protrude forward from the snout and are used to drill through the eggshell, and degenerate after hatching. Most of the ways to implant teeth are lateral movement, and some of them are terminal movement, so both eyes can move independently. Many lizards have salt glands to excrete mineral salts. The shoulder strap exists.

Most lizards have four legs, and their hind limbs are powerful. They can run quickly and change their running direction quickly. Cnemidophorus's speed is 24 kilometers per hour (15 miles). Some lizards have elongated bodies, shortened limbs and even no limbs. Gecko, iguana (Uta) and Acanthosaurus have many edges on their toes to increase their surface area and prevent them from sinking into the sand. Geckos can crawl on vertical glass plates. There are five toes on each foot, and the webbed skin is divided into two groups, three toes on the outside of the hind limb and two toes on the inside, and the forelimbs are opposite, which is suitable for grasping branches. Some terrestrial iguanas and iguanas can run on two hind legs, and their tails stretch backwards and upwards to maintain balance when running. Flying lizard has a skin membrane on its side, which can glide. Male lizards have a pair of joint organs-half penis. King lizards can run over short distances of water.

Lizards live in different habitats, underground, on the surface or in tall vegetation, and can be seen in deserts and islands. The only remaining marine species is the Galapagos sea iguana, which feeds on seaweed. Some kinds of lizards live partly in water and eat fresh water. The most important environmental factor for lizards is temperature. Many species have their "optimum temperature". They will bask in the sun and raise their body temperature above the temperature. Species living in cold regions hibernate. The length of a day also affects lizards. Most lizards lay eggs, which are laid in dug holes, cracks in trees and rocks, or under deciduous layers. Some lizards (especially those living at high altitude and high latitude) are viviparous or viviparous. Most of them don't have the habit of protecting eggs, but in the process of hatching, the skink will stay next to the eggs. A few species (such as lizards and Cnemidophorus) have parthenogenesis. The latter parthenogenesis type is bisexual hybridization. Many geckos lay eggs in the same place. In captivity, the life span of Sheila lizard can reach 25 years and that of gecko can reach 20 years.

Most lizards move during the day, while geckos move between dusk and dawn, making a loud noise (while most lizards cannot make a sound). Lizards hunt by waiting or searching. Many lizards can cut their own tails, and the broken tails can twist quickly to distract predators, so lizards can escape. Many lizards have domain behaviors (including domain performances) or courtship performances. Many species have femoral pores, which may be used to secrete chemicals to attract the opposite sex. Lizards are of little economic significance to people. Some iguanas are edible, while others can get a tan. Geckos live in houses and can catch pests, but may spread salmonella. Lizards are important research materials in biology and are often kept as ornamental animals.

Lizard suborder comes from double temporal fossa, which first appeared in the late Triassic. * * * About 3000 species, divided into 2 suborders, 5 superfamilies, 18 families. A, Ascalabota attached. (1) Gecko Noidea: 1. Gecko family, 82 genera, 650 species, widely distributed in tropical and subtropical regions; 2. Tenebrionidae, 8 genera, 15 species; 3.Dibamidae, 1 genus, 3 species; 4. Ankless family, 1 species, no limbs. (2) Iguanodia: 1. Iguanidae, 15 genus, 600 species, with movable eyelids; 2. Acorus, 33 genera, 300 species. (3) Rhiptoglosoidea, 1 Family: Chamaeleontidae, 2 genera, 84 species. Second, attach Autarchoglossa. (1) scintillator: 1. Tabanidae, about 50 genera, 8 10 species; 2. Family, about 10 genus, 50 species; 3. Sauridae, nearly 20 genera, 150 species; 4. stinkbug family, 40 genera, 200 species. (2) Eellioidea: 1. Eellidae, 7 genera, 67 species; 2. California Ankylosauridae, 1 genus, 2 species; 3. Heterosauridae, 2 genera and 4 species; 4. Poisonous lizards (Liliaceae, chinese forest frog and Nymphaeaceae); 5. Moniliaceae (Moniliaceae), 1 genus, 30 species; 6. Lanthanides, 1 genus, 1 species; 7. Nocturnal lizard family, 4 genera, 12 species.

Amphisbaenia is closely related to sauropods. The body length is cylindrical and the groove is shallow. Without external ear, eyes degenerate. They don't have hind limbs in caves, and they also lack forelimbs except for three genera. Mainly distributed in tropical areas. 15 genus, about 100 species.