Blue Line rider Mark Strotman also snapped a picture of the woman and the alligator with his phone.
"She was sitting with it, petting it, letting people take pictures of it and telling everyone how she raised it from an early age," said Strotman, 23, who initially thought the alligator might have been part of some "crazy Halloween getup" because it on the train just an hour after Halloween turned into Nov. 1.
An hour later, the woman, presumably with the alligator, disembarked the train at the airport. At 2:44 a.m., she is again recorded by the security cameras near the O'Hare stop, but with no reptilian companion.
Strotman said given how fond the the woman seemed of the alligator, he suspects that it might have gotten away from her at the airport. Besides, he told The Associated Press, "You can drop off an alligator anywhere. You don't have to take it to O'Hare."
An airport employee found the alligator later in the day under an escalator near a baggage claim — insert alligator-skin bag joke here. Police captured the reptile by trapping it beneath a trash can.
Not only did officials name the creature Allie, but also handed it over to people who could care for it, just in the nick of time.
"It's not responding well to food... It hasn't had the proper nutrition. Its growth has been stunted. It has a bent spine, soft bones, soft fingernails and a soft skull," Jason Hood, president of the Chicago Herpetological Society, told The Associated Press. The society took custody of the alligator.
Hood said the alligator spotted on the train has the same markings as the animal captured at the airport. It was never a serious threat to the public, too small for its bite to hurt anyone, he said. It's believed to be a 2- or 3-year-old American alligator and its gender is unknown.
Hood says the only way to determine the sex of an alligator is by an internal exam and, he notes, "you want it not to be on death's door before you bother about that."
As for the woman, she could be in trouble because while carrying an alligator bag may be considered stylish, carrying a live alligator is a crime. Hood said the Illinois Dangerous Animals Act makes it illegal to own an alligator in the state.
What's more, the CTA said she could be in yet more trouble.
"Those responsible for this act can face a misdemeanor charge of cruel treatment of an animal or face a fine of $300 to $1,000 for cruelty to animals for abandoning the animal in a public place," the authority said in a news release.
CTA spokeswoman Lambrini Lukidis said releasing the photos provides a good reminder that 3,600 cameras are keeping a close eye on the transit system.
"If a more serious crime is happening in our system," she said, "there are ways for us to work with investigators and the police department."
The decision to release the photos also reflects the public interest in a very unusual sighting, Lukidis said. "We've had deer on train platforms and roosters on buses and trains, but this is the first reptile, at least that I'm aware of."