The group has about 500 members, including about 30 in the Chicago area who open their homes, bathtubs and backyards to reptiles and amphibians who need a place to stay or recover. While by many accounts this was the first alligator found at the airport, it's not the first Floridian reptile found in Illinois that the volunteers have taken in.

The Illinois Department of Natural Resources confiscates a dozen to two dozen alligators every year, said Scott Ballard, the department's expert in herpetology, the branch of zoology that pertains to the study of reptiles and amphibians.

No one in the state, other than zoos and licensed facilities, should have one. Because the reptile is protected by the U.S. Fish and Wildlife Endangered Species Act, a permit is required to own one in Illinois. The state stopped issuing permits for people to keep them as pets about a decade ago, Ballard said. While violators can be convicted of a Class A misdemeanor under the state's Endangered Species Protection Act, a spokesman for the Chicago Police Department said there is no criminal investigation into the abandoned animal at O'Hare.