How do you tell an alligator from a crocodile? And no, dad joke enthusiasts, the answer isn’t that you see one later and the other after a while.

Authorities don't know who dumped a four-foot-long reptile into Lake Michigan, but they now know what kind it is. After initially believing the animal spotted Monday swimming near Waukegan, Illinois, by a startled kayaker was a caiman, officials now say it is actually an alligator.