For a period of roughly 200 million years it looked like crocodiles just might be the ultimate survivors. These creatures, which can grow to more than 20 feet in length, have been around since the Mesozoic Era and endured the massive extinction event 65 million years ago that wiped out the dinosaurs and half the species on the planet. But the encroachment of humans in the past century has endangered the survival of crocodiles throughout the world. The threat to the largest living reptiles is in keeping with the threat to reptiles in general, which are in "even greater danger of extinction worldwide" than amphibians, according to a 2000 study in the journal BioScience.
In 1975 the American crocodile (Crocodylus acutus) was officially placed on the endangered species list, with only 200 to 300 creatures clinging to existence in the southern tip of Florida. Although the animals once roamed halfway up the Florida peninsula, they have been pushed southward by developers, who have torn up their natural habitat - marshes and mangrove swamps - while building strip malls, theme parks and poolside patios.
Thanks to conservation efforts over the past two decades, which tried to protect what little of their homeland remained, the crocodile population has started to rebound, sometimes sprouting in the oddest of places. In 1978 two crocodile nests were discovered amidst the 168 miles of canals that surround the Turkey Point nuclear power plant in southern Florida. Florida Power and Light Company, the state's largest utility, then started a program to protect the animals. Now about 60 crocodiles make their home in the network of saltwater canals outside the plant, where they live undisturbed by humans, feeding on turtles, fish and crabs. In the early 1980s the U.S. Fish and Wildlife Service established the Crocodile Lake National Wildlife Refuge - a 6500 acre marsh adjacent to Turkey Point that provides a sanctuary for crocodiles to nest. The third major breeding area lies in Everglades National Park on the edge of Florida Bay.
All told, the number of crocodiles now exceeds 600, which is a big improvement over what it was 25 years ago, though still a fair cry from the more than 1.5 million alligators in the state. As their home territory gets more crowded, crocodiles have begun to expand their turf, moving as far north as Fort Lauderdale on Florida's east coast and Sanibel Island on the west. In about a decade, if the population continues to expand, the American crocodile will no longer be an endangered species. At that point, the animal will merely be considered "threatened."
More than half of the wetlands in the United States have been lost to human activities and as much as 90 percent of the wetlands in states such as California and Ohio have been wiped out.