CHICAGO (Reuters) - An alligator has taken up residence in a Chicago lagoon, surprising locals after a winter of polar temperatures in the third-largest U.S. city.

Police confirmed the reptile had been spotted on Tuesday in Humboldt Park Lagoon, on Chicago’s west side. It was still eluding capture on Wednesday despite pledges from local officials to trap it.

Authorities aim to have the animal, estimated to be four to five feet (1.2-1.5 meters) long, humanely trapped and relocated to a zoo for veterinary evaluation, said Chicago police spokesman Anthony Guglielmi on Twitter.

Temperatures in Chicago on Wednesday were hovering in the mid-90s Fahrenheit (mid-30s Celsius), in the range when alligators are most active, according to the Florida Fish and Wildlife Conservation Commission.

Alligators can go up to two months without eating and capturing it could be time consuming, said Rich Crowley, president of the Chicago Herpetological Society, a nonprofit organization dedicated to reptiles and amphibians.

“The alligator is still very shy,” said Crowley, explaining it was likely once a pet and was still getting used to the new surroundings. Crowley estimates the alligator to be likely five to 10 years old. They can live to be 80.

Officials warned residents against attempting to capture the alligator on their own and said they had sent out an expert known as “Alligator Bob” to snag the gator.

Alligator Bob is a volunteer who declines to have his full name used. He works with Chicago officials to capture exotic animals, according to Crowley.

“Alligator Bob is the hero we all deserve right now. Give him space and let him humanely catch our new friend,” the 14th District Police Department said on Wednesday in response to several Twitter offers of help.

American alligators normally live in freshwater wetlands and marshes in the Southeastern United States.

The police department warned residents against keeping baby reptiles, pointing out that they could pose a danger once they grow up.