The skin of the Nile crocodile, unlike that of most reptiles, is not shed, but grows with the animal. Although crocodiles look like alligators, they can be distinguished by their longer, narrower snout, and their fourth tooth, which sticks out from the lower jaw rather than fitting neatly into the upper jaw. The adults can reach lengths of over 10 feet and can weigh up to 1500 pounds. The crocodile's eyes and nostrils are on top of the head so it can see and breathe while the rest of it is underwater. As an added advantage, its ears and nostrils can close when it dives, and a nictitating membrane (a transparent eyelid) closes over the eye to keep water out.

Nile crocodiles range all over Africa, eating almost anything (including each other!), but rarely moving away from their chosen body of water. Hatchlings eat small fish and insects; adults will go after turtles, baboons, and even the gigantic wildebeest. They live in large "communities" of several dozen crocodiles, but even there they tend to leave each other alone except during a "feeding frenzy" when they will all unite to take down a much larger animal. Crocodiles swim mostly with their tails. Though their back feet are webbed, they rarely use them underwater. On land, they use their powerful legs to move around. They only look slow; Nile crocodiles have been known to "gallop" at speeds of about 30 miles an hour.