Alert! Deadly man-eating crocodiles from the Nile are invading the swamps of Florida, and scientists have no idea how they got there.

According to The Guardian, a team of researchers from the University of Florida have discovered species of the Nile crocodile called Crocodylus niloticus mingling with native crocodiles in Florida's Everglades National Park and swamps. The Nile crocodiles are said to be the culprit for 480 crocodile attacks and 123 deaths in Africa from 2010 and 2014.

Kenneth Krysko, one of the researchers, said that the Nile crocodiles, which can grow up to 16 feet and weigh 1,600 pounds, did not swim from Africa to the U.S. but they also can't explain how they arrived in the country, Herald Net reports.

Krysko and his team analyzed the DNA of the captured Nile crocodiles, saying that they are interrelated. However, what's puzzling is that it did not match the Nile crocs that are staying in Florida attractions such as Diseny's Animal Kingdom. Thus, the researchers speculate that these Nile man-eating crocodiles may have arrived in Florida illegally through unlicensed reptile collectors who did not contain them properly, allowing them to escape into the wild.

“The odds that the few of us who study Florida reptiles have found all of the Nile crocs out there is probably unlikely. We know that they can survive in the Florida wilderness for numerous years, we know that they grow quickly here and we know their behaviour in their native range, and there is no reason to suggest that would change here in Florida," Krysko said.

The Nile crocodiles add to the growing list of invasive species in Florida together with the spiny lionfish, Cuban tree frog and the Burmese python.

Herald Net notes that if the Nile crocodiles treat the Everglades as its new home, it would pose a problem to the environment and less aggressive American crocodile population, which may be endanger through crossbreeding. Also, Nile crocs are a threat to farms as they are known to attack livestock.