Wildlife biologist Joe Wasilewski has hauled many scaly creatures out of South Florida lakes, canals and marshes over the years.

But the snappish four-footer he snared at the Redland Fruit & Spice Park was an unsettling surprise. It was a young crocodile, but not the typically timid native species. This was a Nile croc, infamous for its appetite for humans and savage attacks on wildebeest and other large animals along African rivers and watering holes.

The capture late last year appears to have been the first sighting — at least officially — of a Nile croc in the wilds of Florida. It wasn’t the last. In April, a botanist photographed a second Nile of similar size on a Krome Avenue canal bank, also in the Redland community south of Miami. After eluding capture for months, that croc is now in hiding, whereabouts unknown. A report of a third, caught in the same area three years ago, has surfaced since.

In a state overrun with exotic invaders, even a few sightings of such an aggressive and dangerous animal have raised concerns with state and federal wildlife managers. In late August, the U.S. Fish and Wildlife Service took the unusual step of authorizing a state shoot-to-kill request for a reptile technically protected under federal law because it is disappearing in its native range and on international threatened lists.

“It was a tough call but we wanted to use common sense,” said Larry Williams, South Florida field supervisor for the service. “We’ve got a protected species but we’ve got it in a place where it’s an exotic.”

No one is predicting Nile crocs will become the next Burmese python, a once commonly sold pet that has settled into the Everglades as a damaging predator. But even a single Nile croc poses a potential threat if it grows to maturity, said Frank Mazzotti, a University of Florida wildlife ecologist helping search for that elusive canal croc. Like the two that preceded it, authorities suspect the still-at-large crocodile escaped from a local breeder, probably as a hatchling.

Big boys of the

crocodile world

Nile crocodiles typically grow larger than their Florida relatives, which top out at around 13 feet.

“A huge Nile or saltwater croc is 16 to 17 feet and probably three or four times the weight of an American crocodile,’’ Mazzotti said. “If it got into a tug of war with a Volkswagen, the Volkswagen would probably lose.”

But what really separates them from local boys is their aggressive nature and habit of stalking and killing large prey, including humans. They’re blamed for hundreds of deadly attacks annually in Africa.

American crocs, largely confined to isolated coastal mangroves in South Florida, tend to steer clear of people. Like any large predator, of course, they can be dangerous. American crocs have been implicated in occasional fatal attacks in South and Central America. But they’re pussy cats in comparison to Nile crocs, said Wasilewski, a consulting biologist and veteran reptile wrangler based in South Miami-Dade. With the small but sudden uptick in sightings, he said the biggest worry is whether more than one Nile could be out there, undetected.

“It’s a frightening situation,” Wasilewski said.

Wildlife managers haven’t issued public statements about the Nile captures or sightings. But on Aug. 23, Nick Wiley, executive director of the Florida Fish and Wildlife Conservation Commission, wrote to federal wildlife managers asking approval to shoot a Nile croc that had eluded repeated efforts to trap it alive. Though federally protected, he wrote, it might pose a threat to humans and was “known to be capable of unpredictable violent attacks.’’