Lizards and snakes are order Squamata in the reptile class of vertebrates. The lizards are in suborder Sauria. The bodies of most lizards found on land are flat from top to bottom (vertically). Those of water lizards are flat from side to side (horizontally), and those of burrowing lizards are usually round and snake-like. Many lizards are brightly colored and some are able to change certain colors quickly.
Lizards move in different ways. A few species have lost their legs as they evolved or else they have small, helpless legs. These kinds undulate like snakes and burrow into the ground. Those with four well-developed legs usually walk or run on all fours, though some of them rear up and run on their hind legs when they are really in a hurry. Geckos have pad-like disks with hooked hairs on their feet and can run up walls and even across ceilings. The so-called flying dragons have wing-like membranes which enable them to glide from tree to tree. A few lizards can swim, as the ancestors of all lizards probably did.
Some species of lizard lay eggs. Others bear live baby lizards. Mother lizards do not take care of their babies after they are born, though some of the egg-laying species protect the eggs from predators.
Lizards eat plants, insects, eggs, fishes, small birds and mammals, and just about anything they can catch and subdue. Usually they seize their food with their jaws, but some kinds, such as the chameleons, shoot out their long tongues to grab insects.
Lizards protect themselves in various ways. Only the Gila monster and the Mexican beaded lizard have poisonous venom. Running away and hiding are usually the lizards' best defenses. Different species have various ways of frightening or confusing their enemies. Horned toads, for example, are protected with spines and are able to squirt blood from their eyes into the face of the predator if they are attacked. The blood contains a substance that many mammals, such as coyotes and wolves, find very disagreeable. Some lizards have a trick of discarding their tails. Sometimes the tail is larger than the rest of the lizard and the enemy fights the tail while the lizard scoots away. It then grows a new tail; the new tail may not be as large or complete as the old. Some lizards hiss and puff up to frighten their enemies. The legless snake lizards and worm lizards are apt to be mistaken for snakes and worms except by experts.
