The 3-foot alligator was a pet, according to Alligator Bob, who is a reptile expert and volunteer with the Chicago Herpetological Society.
"He's too clean, too perfect, to have been living in this river long. Usually they'd have some scratches and gouges from rocks and things," said Alligator Bob. "He's got a decent set of teeth which means someone has been feeding him well. He's got plenty of muscle mass, fat on his tail."
The alligator, nicknamed Sherman by the man who found him, was first spotted on Sunday near Belmont and Rockwell. Another alligator was found nearby on the Chicago River banks earlier this month.
"He'll go through a couple month of quarantine- not that we're worried about the river so much, we know what's in the river. We're worried about what he was raised in," said Alligator Bob. Bob said they have to check for salmonella, which can be a result of an unclean aquarium.
He would have lived in the Chicago River about another month before temperatures got too cool for the cold-blooded animal. Plus, as a pet he probably never learned to hunt for food.
Several people watched the capture- Alligator Bob set out in a boat with a net and was able to catch the small gator. He then put the gator into a white, cloth bag, and brought it onto the banks of the Chicago River.
Nearby residents were grateful for Tuesday's resolution.
"For its own safety. I think it's a good idea it was captured. What are they going to do with it now?" said Helena Segovia.
"The only alligator I like is on my plate. I didn't want to see it or anything. I'm glad they caught it," said Stanley King.Katie Buino brought her kids to look for the alligator from a bridge on the Chicago River. She's using the incident to teach them a lesson.
"Being responsible if you have a pet if you have a pet-- all the way through its life. And if you can't take it to the right place so your pet can be safe," said Katie Buino.
Six-year-old Danny didn't get to see the alligator, but he says it's okay. "I like alligators and other wildlife.... and I like wildlife to stay alive."
If the gator is healthy, he'll be transferred to an alligator farm in the south.