INTERIOR, S.D. (AP) — As the cage door opened, black-footed ferret No. 7505 tentatively peeked his head out, looked hesitantly at the prairie dog burrow offered before him, and then rushed inside, disappearing beneath the earth of western South Dakota's badlands.

His freedom had been months in the making, but in less than a minute — and three decades after his species was believed extinct — he was gone, unleashed into the wild to do what the endangered ferret does best: attack and kill prairie dogs.
"Hopefully, he's chowing down on a prairie dog now," said Paul Marinari, a fish and wildlife biologist with the National Black-Footed Ferret Conservation Center.

The release was invitation-only event at the Badlands National Park, attended by about two dozen ferret fanatics, to kick off a weekend of nationwide festivities celebrating the 30th anniversary of the rediscovery of a mustelid once thought extinct.
On Sept. 26, 1981, a ranch dog in Meeteetse, Wyo., proudly presented his owners with a dead black-footed ferret. A local taxidermist identified the creature, which had been thought extinct for several years, launching a decades-long recovery effort that has seen the ferret population grow from 18 to more than 1,000 in the wild.

The ferret is still endangered, but conservationists are hopeful that by 2020, enough will be in the wild to wipe them off the list.
"We have a responsibility to restore a species that is very much a part of our North American heritage," said Kristy Bly, a wildlife biologist with the World Wildlife Fund. The recovery of the black-footed ferret — called BFFs for short — signifies the health of the grassland ecosystem, she added.

"We're committed to seeing this healthy, living prairie come back," Bly said