South Dakota’s Conata Basin is home to one of North America’s most endangered animals: the black-footed ferret. Once common across the Great Plains, today this native species inhabits only about 2 percent of its original range.
These mainly nocturnal mammals live underground in prairie dog burrows and are quite playful and vocal. They measure 18 to 24 inches long and weigh less than three pounds. The ferret’s yellow-beige color and black markings on its face, feet and tail help it to blend in with its surroundings. It has short legs with large front paws and claws that are adept at digging.
Due to habitat fragmentation and the eradication of the species’ primary food source—prairie dogs—biologists feared the ferrets had gone extinct in the 1970s. Then, in 1981, a rancher’s dog in Wyoming brought home a ferret it had killed. This led to the discovery of a small number of ferrets nearby.
When canine distemper, a disease fatal to ferrets, nearly wiped out this population, the remaining individuals were collected by the U.S. Fish and Wildlife Service and bred in captivity.
From only seven breeding ferrets, conservationists re-established their numbers and began releasing them into the wild. Today there are close to 500 adults, about half in the wild and half in captivity.
From 1996 to 1999, 147 black-footed ferrets were released in Conata Basin, an area where the species had existed historically, and the population began to slowly grow.
But in 2008, sylvatic plague was discovered in Conata Basin. U.S. Fish & Wildlife Service, National Park Service, U.S. Forest Service and Prairie Wildlife Research crews were able to save some of the ferrets by vaccinating them and dusting the prairie dog holes with insecticide to slow the spread of the fleas that carry the plague. Today about 80 ferrets remain at Conata Basin.
Nature Conservancy staff and volunteers have helped save black-footed ferrets in Conata Basin. Watch a video of them in action.
The black-footed ferret’s success in Conata Basin is due in part to the area’s 26,000 acres of prairie dog towns, one of the largest remaining complexes on the continent. Black-footed ferrets prey almost exclusively on prairie dogs and rely on their burrows for shelter and to raise their young.
Black-tailed prairie dogs are a significant species in the Great Plains on which many other animals depend. Their extensive network of tunnels provides homes to burrowing owls, prairie rattlesnakes and numerous other species. They are a critical source of food for many predators, including ferruginous hawks, swift foxes and golden eagles.
A new oral vaccine is being developed to protect prairie dogs from the plague. We hope that it will give prairie dogs, and in turn black-footed ferrets, a fighting chance.