Lizards are mostly quite small, quick-moving reptiles. They have a thick, scaly, and usually smooth skin. Most lizards have four legs and a tail, though some kinds are legless. They have long tongues that they flick in and out to “taste” the air or ground, to pick up information about their surroundings. Geckos also use their tongues to clean their permanently closed, transparent eyelids, while chameleons shoot theirs out to catch insects.
Lizards have a special receptor on their heads that is sensitive to light. This is connected to the brain, and may act as a “third eye”, giving the lizard information about the patterns of day and night.
Lizards are mostly land-dwellers, living all over the world except in Polar Regions. Some are burrowing animals, while many live in trees. Chameleons and some iguanas have prehensile tails to help them climb. Geckos have tiny ridges on their toes and can even walk upside down. Some lizards, such as skinks, are good swimmers, and will dive into the water to escape from predators.
Almost all lizards are meat-eaters, feeding on insects, birds, small mammals and other reptiles. The largest lizard, the Komodo dragon, can reach three metres in length. It is a powerful predator, and can kill large mammals such as cattle. It has even been known to attack and kill humans.
Lizards lay their eggs in warm, damp holes. Most female lizards take no interest in their eggs after laying them, but a few kinds guard the eggs until they hatch.
The smaller lizards have many predators. They defend themselves with camouflage, or by running away, climbing trees or even playing dead. Several species are able to break off their own tails, to confuse an attacker while they run away. The tail has a special “weak point” that can be snapped without harming the lizard. A new tail will grow in its place.
Snakes are a group of reptiles that have long, narrow bodies and tails, and no limbs. Their ancestors, however, were four-legged, lizard-like creatures. Some snakes have two tiny lumps on their bodies – the remains of the hind legs of these ancestors. Snakes have no eyelids. Instead, their eyes have a permanent, transparent covering.
Snakes have many more bones in their spines than other animals. They move by flexing their belly muscles, which are attached to their many ribs. As they move, most snakes curve their bodies into a series of S-shapes, giving them greater speed.
Most snakes lay eggs, and a few kinds will guard them from predators until they hatch. There are some snakes, such as sea snakes that give birth to live young. Young snakes are left to survive on their own.
All snakes are carnivores. Some kinds eat small animals such as snails or worms, but many feed on large prey such as frogs, birds and mammals. Snakes have special loosely hinged jaws that can open extremely wide to take large prey. Their skin can also stretch. They swallow their prey whole, using their sharp teeth to pull it into the throat, and their muscles to squeeze it into the stomach. A snake may need to hunt and feed only every few weeks or even months.
Some snakes have good vision, but most rely on special senses to hunt their prey. Like lizards, snakes are able to collect “tastes” from the air or ground by flicking out their forked tongues. Some kinds of snakes also have heat sensors on their heads that help them to locate live prey accurately, even at night.
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