Conservationists Prowl Swamps to Save Florida Crocs
National Geographic Today
|August 21, 2003|
A conservation success story is crawling through the swamplands of South Florida, northernmost home of the American crocodile, Crocodylus acutus.
The crocodile, whose range extends to Peru, is listed as endangered by U.S. and international wildlife agencies. Thirty years ago, because of hunting and habitat loss, the crocodile population in South Florida had dwindled to less than 400.
Now, though, the number is up to 1,000enough to prompt the U.S. Fish and Wildlife Service to consider down-listing the crocodile's status to "threatened," according to Britta Muiznieks, a U.S. Fish and Wildlife recovery biologist who specializes in endangered South Florida wildlife.
To help preserve the species, Frank Mazzotti and his colleague Mike Cherkiss, wildlife ecologists at the University of Florida in Gainesville, are conducting the longest-running research project and census ever devoted to the American crocodile.
Since 1977 Mazzotti has prowled the South Florida swamps and coastal estuaries in search of the creatures.
"I study crocodiles because they're endangered and ecologically important, and because they're the last of the dinosaurs. They're really our only chance to understand how that group, which once ruled the Earth, was able to survive," Mazzotti says.
To gather biological data, Mazzotti and Cherkiss capture, measure, and tag the crocodiles, then release them. The statistics go into a "croc catalogue" that helps track the species' population growth and survival rates.
Looking for Eyeshine
Crocodile habitat stretches along Florida's coastal estuaries where salt water mixes with fresh and where mangrove swamps shield the reptiles from wind and waves.
"The (crocodile population) recovery has a lot to do with the restoration of the Everglades," Mazzotti says. The natural water flow helps establish the right mix of salt and fresh water for young crocodiles to flourish. Too much salt water imperils them.
During summer, when the crocodile eggs hatch, Mazzotti and Cherkiss board their 15-foot (4.5 meter) skiff and prowl the mosquito-infested swamps of Buttonwood Canal near the village of Flamingo. They've staked out the nesting sites and return to them to catch the hatchlingsmainly after dark. The researchers scan the water with handheld searchlights and head lamps, looking for what they call "eyeshine."
"At night their eyes shine like little bicycle reflectors and it makes them much easier to see," Mazzotti says.
One recent evening Mazzotti and Cherkiss spotted their preyand wielded tongs in the mangrove roots to pluck out three tiny crocs.
Two of them are recaptures, identified by the marked scales, known as scutes, on their backs. The scutes are removed according to a prescribed sequence which gives each animal a unique, and permanent, mark. Mazzotti and Cherkiss weigh the third croc74 grams (2.6 ounces)and mark him.
"Any time you recapture an animal it's exciting, but when you find one that more than a decade has passed since you first tagged it, that's really exciting," Mazzotti says.
American crocodiles can grow up to 13 feet (four meters) and 500 pounds (230 kilograms), and live for 60 years.
Fear of the American Croc
Despite the recent positive signs, "the crocs aren't out of the woods yet," says John Thorbjarnarson, a conservation zoologist for the Wildlife Conservation Society in the Bronx, New York, and an authority on the world's 23 crocodilian species.
It has long been illegal to hunt crocodiles for their hide. But their survival is threatened by loss of habitatespecially the sandy berms where they nestand by humans. Crocodile females roving in search of nesting grounds get hit by cars, the main cause of crocodile mortality.
Public fear of the American crocodile is, in large part, erroneously based on stories of the Nile and Australian crocodiles, which are known to attack and eat humans on occasion. Their American cousins aren't as aggressive.
The Florida crocodiles are also relatively shy by contrast with alligators, who overlap their range but aren't endangered. Crocodiles are lighter in color, with longer, narrower snouts. Also, their teeth are visible even when their mouths are closed.
Mazzotti hesitates to call any crocodilian "gentle," but in all his years of research he has had "no close calls," he says, "no nipped fingers, no scars. I consider riding in my car to the study site a whole lot more dangerous than catching the animals once I'm there."
Mazzotti is eyewitness to the crocodile's recovery. "Biologically the population is ready for reclassification (from endangered to threatened)," he says. "But human intolerance will keep the crocs endangered. This is a success story still in progress."
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