Scientists Rejoice, Floridians Recoil at Crocodile Rebirth
Toothy, tough and terrifying, the crocodile is one of earth’s dogged survivors, and one of man’s worst nightmares.
“They are right up there with sharks, snakes and spiders, one of the few species that commands almost a reflexive fear,” said biologist Frank Mazzotti. “On seeing a crocodile, most people think, ‘This animal wants to eat me.’ ”
In Florida, home of the only crocodiles native to the U.S., that fear helped push the 200-million-year-old reptile to the brink of extinction, even though the American crocodile is not much of a threat to humans. The croc’s hide was coveted for fashionable shoes and handbags, its coastal habitat was perfect for beachfront development and many were killed just for sport.
As recently as 1978, three years after being declared an endangered species, estimates of the U.S. population of the American crocodile fell to 200, and a U.S. Park Service report estimated that fewer than 20 females had nested the previous spring.
Now the beast is back.
Although the American crocodile remains the rarest reptile in North America, “today we have more crocodiles in more places in Florida than we did 20 years ago,” said Mazzotti, a University of Florida professor, who puts the current number of adults at between 400 and 500. “In terms of recovery, I think we can get the population back to what it was before we started altering the habitat, maybe 2,000 to 3,000 animals. I’m cautiously optimistic.”
Developments Provided Croc Habitat
Some of the crocodile’s recovery can be attributed to the type of development that almost killed it off in the first place.
In the 1970s, a massive luxury residential development in Key Largo, about 30 miles south of here, was derailed by environmentalists who predicted ecological disaster if mangroves were removed and people moved in.
At the same time, Florida Power & Light Co. was opening a massive nuclear power plant on a nearby 22,000-acre site on Turkey Point, a hook of land jutting into southern Biscayne Bay, which included a 168-mile maze of shallow canals used to cool down superheated water from the nuclear reactors.
The earthen berms created by the cooling canals, along with the spoil from canals dug for the abandoned Key Largo project, turned out to be ideal for crocodile nesting.
“The dirt is a peat-marl mix, mounded up the way they like it, above the high tide line,” said Joe Wasilewski, a biologist hired by FP&L; to monitor the crocodile. “After we took away the sunny beaches, we inadvertently gave them something just as good.”
This year scientists have located more than 50 nests in Key Largo, in Florida Bay and in Biscayne Bay near Miami in a range that is slowly expanding up both coasts of the Florida peninsula. Adult crocodiles have been found as far north as Fort Lauderdale on the Atlantic coast and on Sanibel Island on the Gulf of Mexico, according to Mazzotti.
Six crocodiles recently discovered on the grounds of the Marco Island airport are between 11 and 13 feet long, “The biggest I’ve ever seen,” said Mazzotti.
Along with serendipitous nesting sites, the crocodile also has been aided by some restoration of the freshwater flow through the state’s midsection. Dams and canals that had cut off much of that southward flow resulted in a rise in coastal salinity that may have disturbed reproduction.
Old Fears Rise Anew
The rebound of the American crocodile has stirred fears among some South Floridians, even those who may be quite familiar with the common American alligator, an animal that can sometimes be seen in a public park or grinning cartoonishly as a university mascot.
Although alligators and crocodiles are cousins (two of the 22 species of crocodilians found throughout the tropics), they are very different animals, scientists point out.
Alligators are blackish in color, have rounded snouts and thrive in freshwater lakes, canals and streams throughout Florida and into the Deep South. There are an estimated 1 million alligators in Florida alone, and they are known to be much more aggressive than the American crocodile. Veteran biologist George Dalrymple theorizes that the croc’s narrow snout and more obvious teeth give it a mean look, whereas the broad-headed alligator “seems to be smiling.”
A Reputation for Shyness
Last year the state’s Game and Fresh Water Fish Commission launched a campaign to educate tourists and residents alike that alligators can show up almost anywhere. “Welcome to Our State. You Might See Some Alligators Here,” read the advertising slogan.
In March a 3-year-old boy was killed when an 11-foot alligator pulled him into a central Florida lake. His was the seventh death in more than 220 documented alligator attacks on humans since 1948.
American crocodiles, on the other hand, are known as shy and retiring. Gray-green in color, crocs have slender, tapered snouts and live in brackish water along the coast where fresh water and salt water mix.
Still, crocodiles do have a bad reputation. In folklore and legend from parts of Africa, Asia and Australia, where saltwater crocodiles can grow to 23 feet in length and weigh more than a ton, the largest reptiles on Earth are often used as symbols of evil.
And they have attacked people. Crocs are said to have savaged almost a thousand Japanese troops retreating through a Burmese swamp during World War II. A Peace Corps volunteer from Cornell University was eaten by a crocodile in Ethiopia in 1966. And 40 passengers on a sinking Indonesian ferryboat were devoured by crocs in 1976.
In Florida, only one crocodile attack on a human has been documented, and that occurred in 1925, when a 14-footer reared up and seized a Biscayne Bay surveyor after he reportedly fired two bullets into the animal. The surveyor died, but the croc survived and was shipped off to a north Florida tourist attraction to perform under the name Zulu.
Here, crocodiles have more to fear from humans than the other way around. Last spring a Key Largo man was charged with interfering with an endangered species after he caught a 9-foot crocodile on a treble hook baited with a chicken. He faces a fine of up to $500 and a sentence of up to 60 days in jail. And last month four men and two teenagers in Plant City, near Tampa, were charged with climbing over a fence at a reptile park and clubbing a pair of crocodiles to death with wooden planks.
The odds of seeing a crocodile in the wild are remote. The casual observer has a better chance of spotting one as road kill along busy U.S. 1, the main highway to the Florida Keys, which passes right through the crocodile’s habitat. An average of two a year are hit by cars, Mazzotti said.
During breeding season, the female crocodile comes up on land to dig a cavity, deposits 20 to 40 eggs in a single night, and then covers the nest with dirt. She usually remains nearby to defend the nest during the 90-day incubation.
During June and July, when the hatchlings begin to stir inside the egg, the female croc uncovers the nest and helps the young get to water.
That is when researchers such as Wasilewski and Mazzotti climb into airboats to search the banks of canals and beaches with powerful searchlights that will give back the telltale red-orange glow of a crocodile’s eye.
On a recent night at Turkey Point, Wasilewski scooped up a couple dozen hatchlings from several nests, often diving over the gunwales of the airboat to grab them. He once had to poke a submerged 5-foot mama in the tail to get it to move off her young.
Once the hatchlings were collected in cloth bags, Wasilewski hauled them back to the laboratory, where he measured and weighed them, injected each with a computer chip ID number and clipped each animal’s scutes, the raised scales on the tail, in a pattern that will reveal where and when each was born if ever caught again.
Mortality among young crocs is high. Only about 10% of hatchlings are believed to survive to adulthood, according to Wasilewski, who has tagged and released 300 young this year. They are routinely preyed upon by large wading birds and fish such as tarpon. Raccoons are notorious for digging up nests.
The American crocodile is endangered throughout its range, which extends southward through Mexico, Central America and to the islands of Cuba and Hispaniola. “Studying a crocodile is giving us a gauge of the overall health of the whole world,” said Paul Moler, a wildlife biologist with the state Game and Fresh Water Fish Commission who has tagged 49 hatchlings in north Key Largo this summer.
“If the animal’s population is decreasing, heading toward extinction, we need to know: Are we poisoning ourselves? Ultimately, it could be our survival at stake.”
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