In a striking turn of events, the Sunshine State is dealing with a new, unexpected predator. Nile crocodiles, native to sub-Saharan Africa, have recently been identified in Florida, significantly expanding their known geographical range. This finding not only poses a fresh challenge to local ecology but also raises critical questions about invasive species management. The discovery has sent ripples through the wildlife and conservation communities, leading to a scramble for understanding and action.

Four Nile crocodiles have been found in Florida by scientists from the University of Florida. Between 2002 and 2004, the researchers studied populations of crocodiles in the state. Previously, using DNA analysis, they found three Nile crocodiles: one was a foot-long hatchling sitting on a porch in Miami. Another was found on the property of a private zoo in Homestead, and a third, also in Homestead, a 10-pound (4.5 kg) female, was captured in a public park.

Finally, more recently, in March 2012, a three-foot-long (1 meter) female was trapped in a canal in Homestead. The researchers tagged this one and released her to nature. Two years later, it was recaptured and the team calculated its growth rate (40.5 cm/year – 15.95 inches/year) and movement. “The most likely route of travel by waterway (i.e., canal) illustrates that this animal traveled at least 29 km (18 miles) from its original capture site.”

How did these crocodiles come to the United States? According to the study that describes the animals, they are probably from South Africa: “Our molecular analyses illustrated that two of the crocodiles we collected are most closely related to Nile Crocodiles (Crocodylus niloticus) from South Africa, suggesting this region as a source population. We, thus, documented the first known introduction of C. niloticus in Florida. Two, and possibly three of the introduced crocodiles shared the same haplotype, suggesting they are likely from the same introduction pathway or source.”

The study also says that one crocodile escaped from the Hendry County facility, and survived in 1,012 hectares of semi-wild habitat for three to four years, confirming that this species can survive in southern Florida.

“There are no signs of the crocodiles reproducing since arriving in Florida”, the study’s authors said. “It’s also unlikely the crocodile population has so far had any impact on native wildlife in the area”.

Nile crocodile – bigger, stronger, and more aggressive than alligator

A group of Nile crocodiles
A group of Nile crocodiles on the banks of the River Grumeti, Africa. Image source: Deposit Photos

Nile crocodiles are the second-largest reptiles on Earth, after the Saltwater crocodile. They are bigger than alligators: they can easily grow to 5.5 meters/18 feet (possibly up to 6 meters – 19.68 feet). The largest (unconfirmed) Nile crocodile is a specimen named Gustave – its claimed size is 6 meters (19 feet and 8.2 inches).

The Nile crocodile is an opportunistic apex predator and a very aggressive species of crocodile that is capable of taking almost any animal within its range. They are widely regarded as more aggressive and dangerous than alligators. Their jaws are also stronger than the alligators. It is one of the most dangerous species of crocodiles: although most attacks do not get reported, the Nile crocodile is estimated to kill hundreds (possibly thousands) of people each year, which may be more than all other crocodilian species combined.

A real story about Nile crocodiles in Florida from our visitor

John Crowder wrote:

In 1972, I worked for the U.S. Fish & Wildlife Service (FWS) in Vero Beach, Florida. One day, responding to a call from the Florida Game and Freshwater Fish Commission, my supervisor, Joe Carroll, and I met two staff of the Commission at an estuarine lagoon a short way south of the State of Florida’s Mosquito Research Laboratory (now the Florida Medical Entomology Laboratory).

One of the State personnel was Larry Shanks, who later worked for FWS; I do not recall the name of the other. The laboratory is about 3 miles south of Vero Beach and lies along the Indian River Lagoon. The State staff had been told that an especially large alligator had been seen in this area. When Joe and I and the State employees arrived at the site, all of us were astonished to see that the reptile of concern was a CROCODILE and a large one.

It was later measured at 12 feet. The crocodile was calmly resting at the surface about 50 feet from where we were standing and gave no sign that it had noticed our arrival.

The State personnel arranged for the beast to be trapped and transported away from the area. it was taken to a location in the Florida Keys known as Lake Surprise and released. Portions of Lake Surprise lie within a wildlife management area near the north end of Key Largo.

American crocodiles are present in that area.

Several days after the crocodile was removed to its new location, one of the State employees called to advise that the crocodile had been determined to be a Nile Crocodile. I do not recall any details of how that determination was made.

We speculated that the crocodile might have been an escape from a tourist attraction nearby, then known as McKee Jungle Gardens, now McKee Botanical Gardens. They formerly maintained captive animals of various species, including crocodiles.

Sources

M. Özgür Nevres

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