American Crocodile

Crocodylus acutus

American Crocodile

American crocodile. Public doman photograph. Credit Judd Pat, National Park Service.

Hang out at a place like Green Cay Nature Center in Boynton Beach especially during the cooler months when the snowbirds are back and tourists abound and you’re almost certain to hear some one referencing the local crocodile population.

Well, no. Alligators, not crocodiles. Same order, Crocodylia, different species.

The odd thing about this odd misidentification is that alligators get a whole lot more pub than our relatively rare crocodiles. After all, gators happen to be Florida’s official reptile per act of the Legislature, and the mascot of one of its flagship university.

Florida does, in fact, have crocodiles, American crocodiles, Crocodylus acutus. But the population is so small that crocs are considered threatened, generally restricted to salt and brackish water and mostly found in southern Miami-Dade and Monroe counties.

The two species are superficially alike, so it’s hard to blame the casual tourist for being unable to tell one from the other. In fact, the U.S. Fish and Wildlife Service maintains a threatened status on alligators despite their robust population, to limit the possibility of a hunter mistakenly killing a croc that he thought was a gator.

Crocs are similar in size to gators, typically between seven and 15 feet in length and weigh as much as a ton. In parts of their range outside of the United States, crocs can approach 20 feet.

However, crocs tend to be gray in color, alligators more black. Their snouts are narrow, like an “A,” as in alligator, while the snouts of alligators are round, like a “C,” as in crocodile. Crocs, when their mouths are closed, expose all the teeth in their upper jaw and one (the fourth) in the lower jaw. Alligators only expose the teeth in their upper jaw.

Florida is the northern most part of the American crocodile’s range; it extends southward through parts of the Caribbean, including Cuba, Jamaica and Hispaniola (Haiti and the Dominican Republic), along the Caribbean coast of Mexico, Central America and Venezuela. They’re also found along the Pacific coast between Peru and Mexico.

In Florida, the heart of the American crocodile population is, as noted above, southern Miami-Dade and Monroe counties. However, theoretically, they can be found as far north as Merritt Island on Atlantic side and Tampa Bay along the Gulf. But the farther north you go, the odds of spotting one become longer and longer. Likewise, they can, theoretically, nest as far north as Lake Worth along the Atlantic but the possibilities of finding one that far north are somewhere between slim and none.

Even though the Spanish began exploring Florida as early as 1513, it wasn’t until 1820s that the first hints emerged that crocodiles inhabited the state, according to the Florida Museum of Natural History. It wasn’t until 1869 that their presence was scientifically confirmed.

Crocodiles were never that numerous in the state most likely because of the occasional cold weather, the Florida Museum speculates. Crocs unlike their alligator cousins have little to no tolerance for cold.

Then, beginning in the 1880s and continuing into the early 20th century, hunters, seeking hides or just plain sport, began taking a toll on Florida’s limited croc population. Later, as South Florida became more and more settled, development began destroying crocodile habitat. By 1975, it’s estimated that the croc population was down to 200 to 300 individuals. The Fish and Wildlife Service placed crocs on the Endangered Species list. The crocodile population began recovering but not just because of the protections its endangered status afforded.

Oddly enough, according to the Florida Museum, it was the construction of the Turkey Point Nuclear Power Plant in southern Miami-Dade County stimulated the turnaround.

The plant needed miles and miles of canals dug to provide the water needed to cool it. The mounds of soil from the dredging happened to be perfect for crocodile nests and the area was off-limits to further development, making it accidently a refuge for the species.

The croc population in recent years has recovered to about 2,000 individuals, Florida Museum estimates, possibly more crocs than ever existed in Florida at any time. The problem for crocodiles outside the United States are the same ones that decimated the population here: habitat destruction and illegal hunting. The International Union for Conservation of Nature rates the American crocodile’s global population as vulnerable to extinction; the Florida Natural Area Inventory rates it as extremely imperiled.

And even as the Florida population has seemingly more than recovered from its low of nearly 50 years ago, new threats emerge — climate change and rising sea levels — that puts the croc’s future in doubt. We’ll explore more in a moment. More croc basics first.

Male crocodiles begin courting the ladies of the species in mid-winter — around January or early February. Males in order to impress the opposite sex will move quickly, slap their heads in the water a number of times and roar, showing off their teeth. Females, if interested, will raise their snouts, arch their tails and return the roar with one of their own. The courtship can go on for days, ultimately culminating with dinner and a movie. We made that up. It will culminate with the two reptillian lovers rubbing snouts and submerging under water.

Beginning in April and continuing into May, females will dig nests in soil high enough to stay dry even at high tide. They’ll deposit between 20 and 60 eggs in each nest, which will require 85 days of incubation before they hatch.

Females will “sit” on the nest, both defending it and keeping it warm. Mom will listen to the nest, waiting for the sounds of newly hatched crocs; she’ll dig them up and transport each one to the water, at which point they’re on their own. Alligator moms, by contrast, stay with their young for the first two years.

Only one in four croc hatchlings will live to celebrate their first birthday, not surprising considering the lack of maternal care. Of course the sheer number of hatchlings sustains the population against the high mortality rate. When the eggs are laid, the gender of the croc-to-be isn’t determined. Oddly enough, temperature will make the difference between who becomes males and who becomes females. Mothers layer their nests with vegetation, which, as it decomposes, heats up. High temperatures — 88 to 91 degrees F produce males; termperature below 88 will produce females. However, if the temperature dips below 82, the eggs won’t hatch.

Here’s where the threat of climate change comes in. Warmer temperatures will likely mean warmer nests, which could produce an imbalance in the number of males and females possibly to the point of threatening the species.

Meanwhile rising sea level could threaten crocodile habitat. Various estimates have rising waters inundating between 30 percent to 98 percent of their current habitat. And influx of salt water could increase salinity levels, with the potential for disrupting crocodile populations.

More crocodile basics: again, they prefer saltwater and brackish water habitats, primarily hanging out in mangrove swamps as well as ponds, lakes, canals and creeks. They will foray into coastal freshwater habitats occasionally.

Like alligators, they dig a network of burrows to keep warm in winter, as a refuge from seasonally declining water levels and as a place to rest.

They are territorial. They will pick an area and stay there as long as it offers a sufficient supply of food. The only exception is during mating season.

The menu for crocodiles includes fish, turtles, frogs, birds and small mammals, which they grab with their jaws and swallow whole. Juveniles eat invertebrates and small fish, while hatchlings eat insects. Crocs will swallow small stones to help them digest their food.

Crocodiles are solitary creatures, often described as shy and reclusive. They’re more likely to flee an approaching human than attack, but they can be aggressive if they feel threatened. They have been known to attack humans.

They can live to 100 years, but most, assuming they survive their “childhood,” typically reach 50 to 70 years. They are at the top of the food chain within their realm.

Crocodiles are members of Crocodylidae, the crocodile family.

Published by Wild South Florida, PO Box 7241, Delray Beach, FL 33482.

Photographs by David Sedore. Photographs are property of the publishers and may not be used without permission.