MEETEETSE, Wyo. – Biologists have released 13 more black-footed ferrets on a ranch where scientists more than 30 years ago rediscovered the slinky predators after they were thought to have gone extinct.

One young ferret raised in captivity in Colorado didn’t take kindly to roaming free Monday. She growled and refused to leave her cage, then attacked a stick used to prod her.

A biologist eventually managed to grab the animal and carry her to her new home on the Pitchfork Ranch. Last year, 35 ferrets were released on the ranch outside the small town of Meeteetse.

Biologists worried the animals had gone extinct until a dog on the Pitchfork Ranch brought one home in 1981, the Powell Tribune reports.

Later, several of the animals were rounded up and used in a captive-breeding program that has helped restore black-footed ferrets at several sites in Colorado, Montana and elsewhere in the western U.S.

Those releasing ferrets Monday included Dennie Hammer, a former U.S. Fish and Wildlife Service employee who in the early 1980s fitted a black-footed ferret with a radio collar and released it back into the wild in the Meeteetse area.

“The idea was, find one, track it and you’ll find others,” Hammer said.

It was a gamble. Hammer worried the ferret would scamper off without leading him to any friends, but biologists eventually counted 122 ferrets. Most died of disease but not before 18 were captured for breeding.

The nocturnal weasels prey on prairie dogs.

Biologists make efforts to keep the colonies free of plague, a disease transmitted by fleas that can kill prairie dogs by the thousand. They dust prairie dog burrows with insecticide and are experimenting with feeding the rodents pellets that contain plague vaccine.