Neal, who asked that only his first name be used, told The Salt Lake Tribune in an email that he kept the reptile in a cooler after ostensibly catching it on Saturday and taking it to the home of his in-laws in Provo.
Dubbed "Alli" by the man's daughter, the gator on Wednesday was reportedly basking in a pond in a fenced yard, while the DWR opened an investigation.
Releasing nonnative wildlife into the wild is a crime in Utah.
"This is a public safety issue. A lot of people recreate in Utah Lake," said Krissy Wilson, DWR's assistant chief for native species. "People aren't aware of the implications of these nonnative species being introduced into the environment. These are illegal activities and have far-reaching impacts on wildlife species as well as the public."
Exotic species have taken a heavy toll on Utah's waterways, particularly from the introduction of fish such as burbot and carp that out-compete native species and disrupt the ecosystem. In Utah Lake, a population of red-eared sliders, a turtle species commonly kept as pets, has become permanently established, due to people who turned loose turtles that were no longer convenient.
Wilson said gators have been recovered from the Jordan River on two or three occasions, but no one was ever prosecuted for releasing them.
"We know people get these baby alligators when they are little and keep them in a terrariums," she said. "Everybody likes them until they grow."
Unless "Alli" crept away from a zoo, her presence in Utah Lake, if confirmed, would indicate someone broke the law.
In the case of alligators, crocodiles and caimans, it is prohibited to possess, import or propagate these predatory reptiles except in the rare instances when someone gets special permission, and even then it would be limited to educational purposes, according to Wilson.
While fishing off a boat for channel catfish Saturday evening, Neal and his daughter were using hardboiled eggs wrapped in bacon as bait, the man told The Tribune.
"I know it sounds crazy, but some of the monster cats love it. Well, apparently gators do to," Neal, who said he lives in Caldwell, Idaho, wrote in an email. He said he pulled the gator out of the water near the Jordan River outflow.
"The gator is very safe here in our small half-acre pond," he wrote. "I don't want any of the readers to think we harmed her or are against gators, we love animals!" Neal wrote.
DWR officials had planned to retrieve Alli on Thursday.
Wilson said if the report is substantiated, she hopes the agency can place the gator with an educational facility or zoo. Another option would be to place the animal with someone out of state who is authorized to keep gators.
If a home cannot be found, DWR will have to euthanize the alligator since releasing it is not an option.
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