A 4-foot alligator taking up residence in a popular Chicago lagoon has now evaded capture and wildlife experts for three days.
So how does a reptile living in an enclosed space avoid traps, crowds and experts for so long?
Here's what we know so far about the creature that has become somewhat of an internet sensation and caught the attention of an entire city.
U.S. & World
When was the alligator first spotted?
Photographer Rencie Horst-Ruiz told NBC 5 she was at the Humboldt Park Lagoon around 6:30 a.m. Tuesday when she saw the alligator and snapped photos. She reported the creature appeared about 4 or 5 feet long.
Illinois Conservation Police and Animal Care and Control responded to the scene hours later to investigate, but Chicago police spokeswoman Officer Michelle Tannehill said they still could not confirm if an alligator was in fact in the water by 5 p.m. Tuesday.
Not long after, police said they had "independently confirmed" the alligator was in the lagoon.
What kind of alligator is it?
“We have been able to determine it is an American alligator. By species, American alligators is, I don’t want to say friendlier, but more laid back than the crocodiles or caimans,” said a representative of the Chicago Herpetological Society, Bob, who asked NBC 5 not to use his last name.
What is being done to capture it?
Animal Control brought in a reptile specialist dubbed "Gator Bob" who took over the effort to place live humane traps Tuesday night.
Gator Bob said early Wednesday that he'd set three traps, declining to share what kind of bait was used so as not to encourage people to come out and set their own traps in the lagoon. Gator Bob added that the creature was "playing submarine - when he sees someone, he dives."
He continued setting up traps Thursday.
"Ideally a net would be the best thing because it’s safe and good for him," Gator Bob said. "But if I have to grab him, I will. We have experience dealing with these animals. I have all of my fingers."
If the reptile is successfully trapped and captured, it will immediately be taken to the nearest zoo to be seen by a reptile veterinarian. Gator Bob said the water temperature as of Wednesday morning was around 82 degrees, and that the alligator likely had about two to three months before temperatures dropped to a point where it would not be able to survive.
Why isn't it captured yet?
Bob says so far, the alligator has been making its way around the lagoon, in a leisurely fashion, avoiding the traps that have been set to bring him in.
"If he sinks down in there, there's no way to tell where he's at," Bob said. "He could be sitting six inches below surface and I can't know where he is at and you can't jump in the water, you can’t use a net, you can't grab him because you can't see and the last thing you want to do is grab the wrong end of a gator."
Experts say gators can go a week between meals and as long as six months without food.
Bob believe the alligator is getting comfortable, swimming around the entire lagoon.
"That's an 8-acre pond, all right? My traps are about 6 feet long," he said.
Bob noted he has been within 30 feet of the creature, but needs to be within 15 to capture it.
"Fifteen, we can catch him with a net, a pole or physically grab him," he said. "If he's over gravel, there's nothing to stop me from diving over and grabbing him. If it's in the mud, I have no chance because I have no footing."
"Think of it like fishing," he added. "Now limit it to a gator. One species out of many in that lagoon."
How did it get there?
American alligators are illegal in Illinois, with Gator Bob speculating that the reptile was picked up elsewhere and its owner got scared and thought dumping the animal in the lagoon was best. But Gator Bob pointed out that exotic animals like this can be turned over to Animal Care and Control.
"This is the first time it’s seen that much water in his life. He’s probably spent life in an aquarium or a bucket," Gator Bob said.
How dangerous is it?
Gator Bob said the alligator is likely hanging near where it was dumped, expecting its owner to come back and feed it. But in about a week, the gator's instinct would likely kick in and it will hunt on his own, mostly at night and sleeping during the day.
As long as you're not swimming in the water, it won't consider you food, Gator Bob said.
"He's so scared of all these 5- and 6-foot tall people, when he is only this big,” he said. “I mean realistically, if he's walking across the floor here, you can step on him and kill him."
That said, with 80 teeth in the gator's mouth, "your hand with get shredded, not torn off," Gator Bob said.
How common are alligators in the area?
According to Chicago Animal Care & Control, the department has rescued only four alligators from Chicago homes, lagoons and lakes in the past five years.
What's happening now?
Crowds have been gathering around the lagoon, hoping to catch a glimpse of the creature they are now calling “Alex” after Alexander Von Humbolt—the German naturalist the park is named for.
Some of those gathered are wearing costumes - even Benny the Bull made an appearance.
“Everybody loves animals, so nobody wants nothing to happen to it but at the same time everybody’s worried about the kids,” said Luis Coss, who has been attentively waiting to see the gator.
But Gator Bob said people have been jumping in the water, fishing and one man even came to the scene with baseball bats.
"I was like, 'Sir, what are you trying do?'" Bob said.
Officials are urging people to stay away from the lagoon and use caution in the area.