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Are Nile Crocodiles Breeding in Florida Everglades?

The presence of Nile crocodiles as recently as two years ago has been confirmed in South Florida.

The presence of Nile crocodiles as recently as two years ago has been confirmed in a place very far from the species' native Africa: the Everglades in South Florida.

Thanks to DNA analysis, researchers from the Florida Museum of Natural History say in a new study that three juveniles of the species (Crocodylus niloticus) found in the Everglades between 2000 and 2014 were indeed Nile crocs.

The big question is: How did three crocodiles of a species native to sub-Saharan Africa end up making a living in the Sunshine State? And, as a key followup: Are there more?

How To Evict Invasive Species: Photos

As for the latter, Kenneth Krysko, herpetology collections manager at the museum and co-author of the study, said it was "unlikely" that the three crocodiles were the only ones.

"We know that they can survive in the Florida wilderness for numerous years," Krysko said in a statement. "We know that they grow quickly here and we know their behavior in their native range, and there is no reason to suggest that would change here in Florida."

World's Top Heavyweight Reptiles: Photos

Their presence would certainly not be welcome. Nile crocodiles are enormous (up to 18 feet long) predators and will devour a wide range of birds, fish and mammals.

If they multiply, they could leap to the top of the invasive species list in Florida, displacing the Everglades' current champ, the Burmese python.

Humans, too, would have cause for concern. The scientists note that in recent years Nile crocodiles have killed more than 100 people in Africa and attacked nearly 500.

VIDEO: Fossil Find Reveals Ancient 900-Pound Crocodile

How did they get to South Florida? The researchers aren't sure. DNA analysis showed that the three juveniles were related, but they could not be linked to Nile crocodiles held in any U.S. zoos.

Whether they were brought to the state illegally and then escaped or were set free remain open questions.

Heads Up: Crocodiles Climb Trees

The scientists say there's no evidence yet that the crocodiles have taken hold in their home state, yet they suggest a risk assessment be performed that games out the possibility of the animals spreading.

"My hope as a biologist is that the introduction of Nile crocodiles in Florida opens everyone's eyes to the problem of invasive species that we have here in our state," Krysko said.

Krysko and his colleagues have published their findings in the Journal of Herpetological Conservation and Biology.

This week we learned that back in the last ice age, the first humans to populate Australia likely had to contend with

a giant lizard

that might have been almost 20 feet long. That got us thinking: Which are the weightiest reptiles among whom modern humans have to live? So here we present the heaviest 10, based on average weight. We'll start small and count up -- getting "fatter," as it were -- until we reach the top heavyweight reptile on Terra Firma. First up, here's the lightest of the top heavies, the false gharial, a freshwater crocodile with a loooong, slender snout. On average, the native Malaysian weighs about 460 pouns (210 kilograms) and runs about 13 feet (4 meters) long.

Pterosaurs Were Super-Social Flying Reptiles

Careful if you find yourself in a dark alley with this fellow, the mugger crocodile. This 495-pounder (225 kilograms) is an accomplished hunter that hides itself and lies in wait to ambush unsuspecting birds, fish, other reptiles or mammals. It can grow to almost 11 feet long om average (3.3 meters). It's the most widespread of India's three crocodile species.

Heads Up: Crocodiles Climb Trees

Here'a a familiar creature, the American alligator, all 530 pounds (240 kilograms) and 11 feet (3.3 meters) of him.

Alligator mississippiensis

, as it's known in the language of taxonomy, is a common inhabitant of coastal wetlands from North Carolina, down to Florida, and across the Gulf of Mexico to Texas.

Otter Vs. Gator: Otter Wins: Photos

Remember the false gharial in our first slide? Well, here's a gharial with no false in front of its name. Weighing in at an average 550 pounds (250 kilograms) and stretching nearly 15 feet (4.5 meters) long, it's sometimes known as the fish-eating crocodile. Its name derives from the unique shaping of the end of its snout, which looks like a kind of earthenware pot whose name in Hindi is ghara. The huge hunter is another of India's three crocodile species (like the mugger crocodile we just met).

VIDEO: Fossil Find Reveals Ancient 900-Pound Crocodile

No slouch in the big reptile department is the American crocodile. We're taking a leap up in size now, as this creature typically runs about 740 pounds, even though it runs a bit shorter in length (13 feet) than, say, the gharial. Though confined largely to southern Florida and Puerto Rico, it still has managed to bounce back as a species. There are a couple of thousand of them now, up from just a couple of hundred in the 1970s. It can eat prey as big as cattle but in general its diet is largely fish-based.

Crocodile Battles Shark In Australia River

Weighing in at an average 770 pounds or so, the black caiman is One. Enormous. Crocodile. The carnivorous beast lives in the Amazon basin and other freshwater habitats in South America. It can be uncomfortable to think about, but the larger of these crocs can and will eat cute mammals like sloths and monkey. Deer aren't safe either, nor are cattle, horses or dogs.

Alligators And Crocodiles Use Tools To Hunt

Did you wonder if we'd ever come to a top heavyweight reptile that wasn't an alligator or crocodile? Here we are! Meet the leatherback sea turtle, the biggest turtle of them all. Unlike other sea turtles, this 800-pound (364 kilogram) creature doesn't have a bony shell. Instead its upside is skin and and flesh. The turtle's range varies widely in the Atlantic and Pacific Oceans. They eat jellyfish, almost exclusively, and are known for migrating many thousands of miles between nesting locations. Lengthwise, they run about the size of an NBA small forward, at 6.6 feet (2 meters).

Sea Turtles From Shell To Surf: Photos

It's back to crocodiles now, with the orinoco. This monster runs nearly 850 pounds on average, nearly 400 kilograms. The species is listed as critically endangered and exists, in small numbers, only in freshwater habitats of Colombia and Venezuela, especially the Orinoco River. The apex predator will take a shot at anything -- birds, mammals, reptiles. But it mainly eats fish. On land or in water, it stealthily stalks its prey. There are reports it has eaten other, smaller crocodiles like caimans and even consumed members of its own species.

Crocodiles Just Wanna Have Fun: Photos

"See you later, alligator! In a ... Nile crocodile???" The Nile crocodile is the second-weightiest reptile in our gallery, tipping the scales at an average of 900 pounds (410 kilograms) and stretching the tape measure to just under 15 feet (4.5 meters). It can be found in aquatic habitats all over Sub-Saharan Africa. The apex predator stalks marshes, lakes, and rivers, eating the usual crocodile diet of mammals, other reptiles, fish, and birds. Their vise-like jaws clamp down so hard that prey just have no chance. They have a structured social order that hands the biggest, oldest males the best places to bask in the sun and first dibs on food.

Croc Ancestor 'Carolina Butcher' Ruled Before Dinos

Finally, we've arrived at the world's biggest extant reptile, the saltwater crocodile (

Crocodylus porosus

). It weighs on average just under 1,000 pounds and stretches 15 feet long (450 kilograms, 4.5 meters). It can live in saltwater but prefers places like lagoons, deltas, and swamps. They have an incredibly wide range, the widest of any of today's crocodiles -- from northern Australia, thoughout southeast Asia and the east coast of India. And it's our third of India's crocodile species, along with the mugger and the gharial. True to its size, there's almost nothing it won't consider prey. The ambush master will take on mammals, fish, reptile, birds, fish, crustaceans -- you name it. They're thought to have the most powerful bite of any living animal. Steer clear of this one, if you value life and limb.

Oh Snap! Dino-Era Croc Jaws Filled Many Roles