Lowry Park Zoo assists in Key Largo wood rat repopulation

With some help from Lowry Park Zoo, a species of rat has returned to its native habitat after being pushed to the brink of extinction more than 25 years ago.

Seven Key Largo wood rats born in captivity were released at Crocodile Lake National Wildlife Refuge last week, officials said. Seven more will be taken to the refuge on Feb. 22.

Some of the rats were raised in captivity at Tampa's Lowry Park Zoo. The zoo started its breeding program in 2002 after researchers determined that fewer than 90 wood rats remained in the Key Largo area. Disney's Animal Kingdom started its own breeding program in 2005.

The rodents' natural habitat is the tropical hardwood hammock forests from Key Largo south to Tavernier. The small mammal went on the federal endangered species list in 1984. Development, Burmese pythons and other animals are to blame for the wood rats' population decline, U.S. Fish and Wildlife Service officials said.

Little was known about the nocturnal animals' social structure, reproductive biology or ecology, researchers said. Veterinarians at Lowry Park Zoo said they have since discovered that wood rats are not social creatures and that females tolerate the presence of males only for breeding.

When breeding is successful, females typically produce only two litters per year, with one to three pups per litter.

"Conservation starts at home," Lowry Park Zoo veterinarian David Murphy said. "It's an exciting time to see this program come full circle with the release of captive born wood rats into their native habitat."

When they arrive at the wildlife refuge, the wood rats were put in individual enclosures with nests designed and built by refuge volunteers. Each animal will be fed for about seven days until the enclosures are removed.

Then the wood rats must learn how to find food on their own.

"We expect them to cache food in the nest structures which will hold them over as they learn to find native food," said Sandra Sneckenberger, a biologist at the wildlife service's South Florida office. "Their caches will help in the short term, but eventually making a full transition to native leaves, fruits and seed will be a critical step."

Right now the rats are working on their nests and most of them are making use of as much native vegetation as they're given, biologists said.