American alligators inhabit lakes, ponds, rivers and swamps throughout the southeastern United States. While their predatory habits influence many other species, it is their habit of constructing “gator holes” -- which become habitat for other species -- that leads scientists to classify them as a keystone species. While other crocodilians, such as estuarine crocodiles, are capable of traversing through and living in saltwater, the American alligator cannot tolerate high salinity for very long.
Alligators in the Keys
American alligators have lived in the Florida Keys since the first Europeans explored the islands. In 1983, Terri Jacobsen authored a multi-year study of Alligators living in the Keys. Publishing the results in “Florida Field Naturalist,” Jacobsen found 133 living alligators; more than 50 of these were hatchlings or juveniles, thus demonstrating that the adults were reproducing in the area. Alligators of the Florida Keys most commonly inhabit freshwater habitats away from the coast.
Not Adapted for Saltwater
In 2007, researchers Kate Jackson and Daniel R. Brooks investigated the small sensory organs on the heads of crocodilians. Publishing their results in "Amphibia-Reptilia," the team found that while all crocodilians detect pressure changes with the organs, crocodiles -- but not alligators -- detected salt with these organs. This capability probably explains why crocodilians are able to cope with saltwater while alligators cannot tolerate it for long periods.
- George Doyle/Stockbyte/Getty Images