Environment

Nile crocs found in Everglades likely related, study finds — and more may be out there

This juvenile Nile crocodile, first captured in 2012 and recaptured in 2014 in the northeast corner of Everglades National Park, near Southwest 168th Street, nearly doubled in size in two years, a rate faster than native American crocs.
This juvenile Nile crocodile, first captured in 2012 and recaptured in 2014 in the northeast corner of Everglades National Park, near Southwest 168th Street, nearly doubled in size in two years, a rate faster than native American crocs.

Three Nile crocodiles, the bigger and meaner cousin of native American crocs, found in marshes in South Miami-Dade County since 2009 likely from the same place, a new study reports.

Using DNA, University of Florida biologists also confirmed the crocs don’t come from any known captive populations. Two of the crocs had nearly identitical DNA and the third was closely related, said co-author and UF biologist Frank Mazzotti.

Biologists don’t think the crocs, feared for their brutal attacks on humans in their native ranges, are breeding in South Florida. But they suspect there are at least a few more left in the wild.

I don’t think we’ve pulled out the last one yet.

University of Florida biologist Frank Mazzotti

“I’ve heard of enough sightings of a strange looking croc in the areas that are connected to this to make me think it’s possible,” Mazzotti said, though not in significant numbers. “But yeah, I don’t think we’ve pulled out the last one yet.”

More worrisome is the success of the crocs in the wild, which grew bigger faster than native crocs and could spell trouble if they were to start breeding. One croc nabbed in 2012 and released before captors realized the croc was an invasive Nile, nearly doubled in size by the time it was recaptured two years later. That rate was also 28 percent faster than crocs from its native range. Another croc that escaped the Billie Swamp Safari in Hendry County managed to survive on its own for four years before being recaptured.

We know their behavior in their native range, and there is no reason to suggest that would change here in Florida.

Florida Museum of Natural History herpetologist Kenneth Krysko

“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,” Florida Museum of Natural History herpetologist and co-author Kenneth Krysko said in a statement.

While no one’s suggesting the Nile crocs may become the next Burmese python, their presence does raise concern. This species, commonly found in South Africa, can live in colder regions — a range that would extend as far north as Savannah, Ga. A special state permit is required to legally possess or breed Nile crocs in Florida but there is fear that illegal trade in the reptiles could increase the risk of more escapes.

The scientists also ran into some bureaucratic roadblocks that could make managing the crocs difficult. Because Nile crocs are considered an endangered species, the team had to obtain special permits to capture them, even though they are considered invasive in Florida.

While few in number, the team is hoping the attention drummed up by the man-eating reptile will draw more attention to the threat posed by any invasive species.

“Now here’s another one,” Krysko said. “But this time it isn’t just a tiny house gecko from Africa.”

Travis Correll, zoological operations manager at Alligator Adventure in North Myrtle Beach, feeds Utan, King of the Crocs. Utan is almost 19 feet long and weighs over a ton. The hybrid of a salt-water crocodile and Siamese crocodile's favorite mea

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