Florida’s Invaders: The Spectacled Caiman

Florida’s most famous resident is the American Alligator. But the state is also home to one of the Alligator’s much smaller cousins–which is not supposed to be here.

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Spectacled Caiman

In the late 1940’s and early 1950’s, Florida was undergoing a tourist boom, as post-war middle-class Americans with disposable income sought vacations in the land of sun and sand. And one of the most popular “souvenirs” that tourists brought home with them were baby American Alligators. Since baby gators don’t remain “babies”, most of the ones that survived the often-improper care they received were set loose outside somewhere (or, as legend has it, were flushed down the toilet to populate the underground sewer tunnels).

By 1960, legal steps were taken, at both the state and federal level, to first regulate and then to completely ban the trade in baby Alligators. So, the pet industry made a substitution–dealers began importing juvenile Spectacled Caimans (Caiman crocodilus) from Central America. These were often sold as “Alligators” or “Dwarf Alligators”, and most of the people who purchased them probably never knew the difference. By 1970, tens of thousands of baby caimans had entered the US. Most of them, like the baby Alligators before, quickly died.

The few who survived soon got too big and too hard to handle, and were often dumped by their owner. In most places, these quickly died too: caimans are very susceptible to cold and cannot tolerate winter temperatures in the US. The sole exception to this was South Florida, where the climate suited them. By 1968, Spectacled Caiman nests were being found in Dade County, confirming that a breeding population had already been established. By 1974, there were enough Caimans in Florida to alarm state wildlife officials, who introduced a program to exterminate them from the area around Homestead Air Force Base. That effort failed, and the Caiman continued to spread. They got a boost in 1992, when Hurricane Andrew destroyed a number of exotic-pet breeding facilities and released a number of species, including Spectacled Caiman, into the wild.

Today, there are breeding populations in Dade and Broward Counties, and non-breeding groups have been sighted as far north as Palm Beach and Seminole Counties. In addition, breeding colonies have become established in Puerto Rico and in Cuba (where the Caiman is a competitor with the endangered Cuban Crocodile). Individual escapees have been reported all over the US, but only southern Florida provides a climate in which they can survive the winter.

The Spectacled Caiman is one of the smaller crocodilian species. In its native range, from southern Mexico to northern Argentina, it can reach a length of eight feet; in Florida it does not seem to get any bigger than five or six feet. The name comes from a curved ridge of bone across the face just in front of the eyes, which make it look as if it is wearing glasses.

Although it is shy and not aggressive towards humans, the Spectacled Caiman will readily defend itself if it is cornered. It is an opportunistic feeder, taking anything from aquatic birds to fish to large insects. The state of Florida considers it a potential threat to waterbirds, and also a potential competitor for space with the Alligator and the endangered American Crocodile (though ecologically the Caiman prefers fresh water while the Crocodile inhabits brackish areas). In addition, the Spectacled Caiman is a carrier of tongue-worms which can parasitize native fish species.

In areas where they can breed, the females will construct nests on shore from rotting vegetation, and lay up to 30-35 hard-shelled eggs inside. As these incubate, the mother will guard the nest from predators, and then helps dig out the babies once they hatch. The young Caimans will stay with their mother for several months until they are big enough to go off on their own. It’s not unusual for an adult female to stand watch over a large group of youngsters from several different mothers. Baby Caimans are eaten by Florida’s egrets and herons, as well as by large turtles and raccoons. As with other crocodilians, the sex of the hatchling is determined by the temperature at which it incubates: cooler temperatures produce males, and warmer temperatures produce females. The hatchlings are bright yellow and black, but fade to a greenish grey as they get older. They reach maturity in about four years.

Because most of their skin is studded with bony plates, Spectacled Caimans are not valued very much for their leather. Like all crocodilians, however, they are legally protected and their international trade is regulated. In most areas of South and Central America, Spectacled Caimans are not considered to be seriously endangered, though the Colombian populations are threatened.

Since Caimans are so sensitive to weather, they have so far been limited to the extreme south of Florida and do not appear to be expanding their range. As a result, state wildlife officials have given it a low priority, especially since the attempt to eliminate the species in the Homestead area was unsuccessful. As long as they stay at a low density and do not appear to be harming the native American Crocodile populations, Florida seems content to just allow Mother Nature to keep the Caimans fenced in.

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