A 10-foot boa constrictor captured by deputies and Key West International Airport authorities Thursday night most likely is a released or escaped pet and did not make its way to Key West from the Florida Everglades, officials said Friday.

"This is a large red-tailed boa," Marathon veterinarian Doug Mader said Friday in an email to The Citizen. "It looks, in the photo, very healthy, so I suspect it is eating plenty."

The boa constrictor was found at 6:30 p.m., right behind the terminal near a grassy area, said Monroe County Airports Director Peter Horton.

The snake is not a Burmese python, the non-native species wreaking havoc in Everglades National Park, Mader said. Pythons have been reported in the Upper Keys, but don't appear to have made it much farther south -- yet. Scientists have been closely monitoring the python's southward march in recent years.

"I suspect it is somebody's pet," Mader said. "Red-tail boas are rare in the Glades. I would check the local pet stores and find out who comes in once a month to buy rabbits or really large rats."

He said red-tailed boas are not a species of special concern, and they are legal to own.

Mader is the consulting veterinarian for the Key West Aquarium, the Marathon Sea Turtle Hospital, The Key West Butterfly Conservancy, the Theater of the Sea and the Monroe County Sheriff's Office Animal Farm.

Airport authorities turned the snake over to Florida Fish and Wildlife Conservation Commission (FWC) officers, Horton said.

Scientists are wondering, but not yet alarmed, about an assortment of boa constrictors that have been popping up in Big Pine Key and No Name Key in the past five or so years.

"Snakes don't tend to get that big and fat in the wild," said Jim Duquesnel, a U.S. Geological Survey (USGS) scientist who is part of a research team in Key Largo that focuses on big snakes and their encroachment into Monroe County.

So far, there have been no reported sightings of baby boa constrictors in the Keys, Duquesnel said.

"The number of boas are so few and far enough apart that they're not finding each often enough to mate," Duquesnel said, adding that boa constrictors are mating in the Everglades alongside pythons.

Researchers want people to report any big snakes they see, fellow USGS scientist Robert Reed told The Citizen in May after a number of boa sightings.

On Aug. 31, FWC officers captured a 9-foot python near Mile Marker 105 in Key Largo. That snake was believed to be a Everglades snake and not someone's pet, according to FWC scientists.

The snake captured at the airport must have been living in the area for a while, Horton speculated.

"For a snake that size, it's a well-fed snake," Horton said. "We're near the largest natural area on the island with the salt ponds and mangroves and we've got all sorts of critters out here to eat."

Residents are encouraged to report sightings of large snakes by calling 888-483-4681.

"We need people to call that line so we can perform a necropsy and determine if the animal has been eating feeder rats or wildlife," Duquesnel said.

alinhardt@keysnews.com