Forget the urban legend about alligators in the sewer. There's a real crocodilian swimming in the Kishwaukee River. “It's true. We've seen it,” said Bob Drake, director of environmental health at the DeKalb County Health Department. “It's just a little bitty thing, only about 3 feet long, that somebody let go.” Officers with DeKalb County Animal Control, which is overseen by the health department, tried last week to catch the reptile in the river near the Northern Illinois University lagoon, but the animal is both skittish and fast, Drake said. The first sighting was anonymously reported to animal control about three weeks ago, he said. Drake said the animal appears to have been well cared for as a pet. He theorized that its owner set it loose in the river. It is illegal to keep alligators or any “life-threatening reptile” as a pet in the state of Illinois, but Drake emphasized that anyone who has one should call animal control to take care of it. “We'll come and get them and take them to a proper wildlife center,” he said. “You're just dooming it to death by letting it go.” Judging by the size of the animal and its bright yellow stripes, it is likely a juvenile, only a few years old, said herpetologist Rob Carmichael, curator of the Wildlife Discovery Center in Lake Forest. American alligators are about 6 to 8 inches at birth, and under ideal conditions, grow 1 to 2 feet a year until they reach maturity at age 6, according to information from the Smithsonian National Zoological Park. The average adult male American alligator is about 11 feet long, and the average adult female about 8 feet long. But Carmichael, who studies reptiles and amphibians, said there is no way the animal in the Kishwaukee will reach adulthood if it's not caught. “Alligators can handle cool weather, but once the temperature gets below about 50, eventually it's going to die,” he said. “They're not adapted to living in this climate. In Florida, they may experience short periods of time where the temperature might reach the 30s, but they also warm up fairly quickly.” Carmichael said the animal is probably eating a lot of fish and any birds or mammals near the water's edge small enough for it to overpower. It poses virtually no danger to humans, he said. “A 3-foot alligator is going to be afraid of even a small child,” he said. “Alligators are very much afraid of people. It's not until they reach their adult size people could potentially be on the menu. With one this young, there is little to no risk.” Animal control has set out cages baited with chicken in areas where the animal was sighted, Drake said. People who see the alligator can either call animal control directly or call police. Officers will continue efforts to capture it as sightings are reported, he said. If the animal is captured, it will be taken to an appropriate wildlife center. DeKalb Police Lt. Gary Spangler said Thursday that he is not aware of any sightings reported to the DeKalb Police Department. The fact that the animal was sighted in northern Illinois is not unusual, Carmichael said. Herpetologists have been rescuing a growing number of abandoned pet alligators in the Chicago region in recent years, he said. Report sightings DeKalb County Animal Control officers are trying to catch what they believe is a small alligator in the Kishwaukee River. Anyone who spots the reptile is asked to call animal control at 815-748-2427 or police at 815-748-8400.