Coral Gables, Fla. ? Listed as a federally endangered species in 1975 after hunting and habitat loss nearly wiped it from the wild, the American crocodile has surged to numbers not seen in a century. Today, the population is about 2,000 at the southern tip of Florida, the species’ only U.S. habitat, where the U.S. Fish and Wildlife Service has downgraded its status to threatened.

As it returns to its historical range — now populated by millions of humans — the American crocodile, which can grow to 15 feet, will be living more in people’s backyards, especially those closest to the coast.

It’s alarming to some residents, even in a state that already has more than a million alligators. Florida wildlife officials get thousands of complaints every year from residents fearful of gators, which can eat dogs, cats, and, very infrequently, people. About 140,000 problem alligators were killed in Florida between 1977 and 2007.

American crocodiles have never made a documented attack on a human in the U.S. Here, it’s domestic pets that more often become crocodile food.

Alligators can be found in any freshwater body throughout the state, likely part of the reason for so many attacks on humans — at least 312 unprovoked ones in Florida since 1948, 22 of them fatal — but crocodiles are confined to South Florida.

They need warmer temperatures, and live where salt and fresh water mix. Florida is the only place where alligators and crocodiles coexist.