South Florida already has its share of threats, from tornadoes to flesh-eating bacteria lurking in ocean waters. Now residents can add people-eating crocodiles to the list.

Nile crocodiles, which can grow to 16 feet in length and tip the scales at 1600 pounds, have been positively identified near Miami, herpetologists confirmed to the Orlando Sentinel Thursday. (One was discovered as a hatching on the porch of a home.) The crocs cause a reported 200 fatalities in sub-Saharan Africa annually. According to National Geographic, the animals mostly dine on fish "but it will attack almost anything unfortunate enough to cross its path, including zebras, small hippos, porcupines, birds, and other crocodiles. It will also scavenge carrion, and can eat up to half its body weight at a feeding."

The researchers, who recently published their findings in the journal Herpetological Conservation and Biology [PDF], don't know how the species made its way to southern Florida. Two of the four animals found so far—which were captured between 2010 and 2014—are related, and a third may also be kin. Their genetic profile isn’t a match for crocs at local habitats like Disney's Animal Kingdom, so escape is an unlikely explanation. (The fourth croc did escape from a "safari" theme park on a reservation and lived in the wild for four years, but the researchers were unable to obtain a tissue sample from it.) It’s possible that an animal smuggler lost track of them or that someone intentionally released them in the Everglades. 

While it’s too early to tell if the Nile croc captures hint at an infestation, Florida has a history of struggling with invasive species. In 1931, a Cuban tree frog hitched a ride in packing materials before multiplying and gobbling up Florida’s delicious native frogs, and the state conducts an annual Burmese python hunt to corral the predator’s population in the Everglades. 

[h/t Orlando Sentinel]