An April 2016 study in the journal Herpetological Conservation and Biology has confirmed the presence of Nile crocodiles (Crocodylus niloticus), native to Africa, in South Florida.
These massive, predatory beasts can grow up to 20 feet (6 meters) long and weigh more than 1,600 pounds (725 kilograms). The possibility of Florida becoming host to an invasive population of Nile crocodiles is somewhat frightening, given their reputation as a predator of large mammals, including human beings. In their natural range, they are responsible for hundreds of attacks on humans every year.
Fortunately, the researchers only found three so far, and they suggest there's no evidence of an established, reproducing population in Florida. But at least one of the introduced crocodiles was an animal that was recaptured after several years in the wild, during which it not only survived, but grew 28 percent faster than some Nile crocodiles in their natural range. So it seems possible that South Florida would make a more-than-suitable home for any population of Nile crocodiles attempting to become a permanent part of the local fauna.
So how did these African crocodilians arrive in North America? There's no chance they swam across the Atlantic Ocean, so someone must have brought them. Identical genetic markers demonstrate that at least two of the animals sampled in the study were directly related to one another, meaning they probably came from the same source. But what was that source? Nobody knows, but researchers suspect the pet trade. If you personally feel the temptation to import an apex predator from one continent to another, ecologists would urge you to reconsider.
There are many introduced and invasive species already thriving in the state of Florida. The Everglades in particular are home to many invasive plants, fish and reptiles. For example, South Florida is today dealing with an invasive population of Burmese pythons, which prey on local wildlife and can do great damage to the local food web.
It's worth emphasizing that if you're a resident of South Florida, there's no reason to panic about invasive man-eating crocodiles just yet. There is not currently a known danger of Nile crocodile attacks in Florida, but if you're really concerned about how to be safe in croc-infested areas, here are a few tips. First: If you see a crocodilian, do not go near it, and definitely don't try to capture or kill it. No good will come of this. Move away and alert the relevant authorities. Second: Avoid water. More than 92 percent of Nile crocodile attacks occur in the water, during swimming, wading or just being at the water's edge. This general principle holds true for other species of crocodilians as well – if you're not sure whether water is safe for swimming or wading, stay out.