American crocodiles are big reptiles; males routinely grow to 15 feet in length. They're opportunistic predators, feeding at night on fish, crabs, birds, turtles, snakes, and small mammals. They're also shy and reclusive, particularly during their nesting season. Crocodiles nest in secluded areas -- unlike their close relatives, the alligators, who will nest almost anywhere they can find suitable vegetation. There are very few active crocodile nests in Florida. To reach adulthood, the young crocodiles need to survive at least two years, when they'll be large enough to discourage predators. Baby crocs are eaten by raccoons, birds, crabs, and even adult crocodiles. Only a small fraction of the hatchlings make it.

Today, human population pressures in southern Florida take an additional toll on young crocodiles. Dams built to supply water for homes, cities and farms greatly reduce the flow of fresh water from Lake Okeechobee into Florida Bay. As a result, the salt content of the bay is rising dramatically. Adult crocodiles can tolerate salt water, but hatchlings can't. They need fresh water to survive. So even in the few remaining nest sites, they are increasingly in harm's way.

"I Thought It Was a 'Gator"
Alligators are one of the principal threats to crocodiles. But the threat is not directly from the alligators themselves; it's from people. Alligators were once endangered in the U.S. as well, but -- thanks in part to protections afforded by the Endangered Species Act -- they've made an impressive comeback. In 1987, they were downgraded from Endangered to Threatened. Now they are so numerous in Florida that they are sometimes destroyed as nuisances. The problem is that most people can't tell the difference between the two species. Many a crocodile has been killed because someone "thought it was a 'gator."

Here's how to tell a crocodile from an alligator:
Look at the lower front teeth. On both sides of the lower jaw of crocodiles, the fourth tooth from the front of the snout is visible when the animal's mouth is closed. When an alligator's mouth is closed, you can't see any of its lower teeth. Alligators have a broad snout. Crocodiles have a narrow snout. Alligators' coloring is darker than that of crocodiles. If you hear one of these big reptiles bellowing, it's an alligator. Crocodiles don't bellow and are far less vocal in general. Now you can tell the difference between the two animals -- but since most people still can't, conservation biologists have urged that alligators be kept on the Endangered Species List until (and unless) the crocodile can also come back. That way, the crocodile won't suffer from so many cases of mistaken identity.