They are among the most ancient of all backboned land animals, and are found all over the world's warmer regions, on land and in water.
Reptiles are especially well-adapted to survive in hot deserts.
Hot and cold Reptiles are often said to be cold-blooded. Reptiles can survive on very little food, but must continually shuttle between warm and cold places to avoid getting too hot or too cold. So they adjust their lifestyle according to changes in their surroundings. Reptiles such as lizards spend hours basking in the sun, soaking up its warmth and gaining energy to hunt. Once they are warm enough, they scurry off to find food, rest in the shade for a while, then bask again.