ENDANGERED SPECIES
Status: Federal Endangered
State Endangered


BLACK-FOOTED FERRET
(Mustela nigripes)

Description

The black-footed ferret's name describes the animal's black feet that contrast with its light tan body. This mammal also has a distinctive black mask, and a black tip on its tail. Along with the badger, skunk, and mink, the ferret is a member of the weasel family (Mustelidae). It is a thin creature, 20 to 24 inches (51 to 61 cm) long, including the 5 to 6 inch (13 to 15 cm) tail. Ferrets weigh 1-1/2 to 2-1/2 pounds (675 to 1125 grams). Males generally weigh more than females. Ferrets have short legs, long claws on the front feet, and large ears. At night, their eyes reflect a bright, emerald green in artificial light.

Black-footed Ferret Collection Sites

Distribution

Black-footed ferrets once ranged throughout the Great Plains, from Southern Saskatchewan to Texas. Their historic range coincided with the ranges of several species of prairie dogs and included portions of 12 states. Although ferrets once lived in the western two-thirds of South Dakota, there have been no confirmed sightings of ferrets in the state since the early 1970's. The last known South Dakota populations were in Mellette and Todd counties, in the south-central portion of the state. Today, the ferret is known to survive only in captivity and in one small reintroduced population in Wyoming. 

Natural History

Ferrets live and raise their young in prairie dog burrows. Prairie dogs are large, burrowing rodents, members of the squirrel family, that live in colonies, or "towns." Although ferrets may occasionally eat mice or rabbits, they eat prairie dogs almost exclusively and cannot survive for extended periods away from prairie dog towns. Ferrets are nocturnal, sleeping up to 21 hours per day and hunting prairie dogs primarily during the night. Ferrets and prairie dogs are so closely linked that the Lakota people called the ferret pispiza etopta sapa, or "black-masked prairie dog."


Figure 1. Black-footed Ferret In A Prairie Dog Burrow

Significance

The black-footed ferret is an important member of the Great Plains prairie ecosystem . As a predator, it fulfills its role as one of the animals that keeps prairie dog populations in check. Like all native species, it plays a unique role that cannot be filled by any other animal. Each species is like a crucial piece of a complex jigsaw puzzle, and every piece is essential to make the puzzle complete. The demise of the ferret and other prairie species is a reminder that the prairie ecosystem itself may be threatened.

Conservation Measures

Between 1900 and the present, people have waged war on prairie dogs. They often are considered pests because they eat grass that is also eaten by livestock. Poisoning and other control measures, along with disease, agriculture, and urban development, caused prairie dog populations to decline drastically. Today, it is estimated that less than 5% of the prairie dog populations that once thrived on the Great Plains still exist. As their food supply was eradicated, ferrets could no longer survive, and their numbers decreased sharply. In 1967, the black-footed ferret was listed as an endangered species. By the 1970's, only a few ferrets were known to exist, and by 1980 the species was feared to be extinct.


Figure 2. Prairie Dog Colony

In 1981, a population of no more than 129 black-footed ferrets was discovered in a prairie dog colony near Meeteetse, Wyoming. Biologists studied the ferrets extensively. When their numbers declined drastically due to an outbreak of canine distemper, a fatal disease for ferrets, the remaining 18 animals were taken into captivity in an effort to increase their numbers through captive breeding. The captive breeding program has been successful, and captive ferret populations now live in special facilities in six states and one Canadian province. Keeping captive ferrets in a variety of locations eliminates the possibility of losing the entire population to a disease outbreak or other disaster at one facility.

The purpose of the captive breeding program, however, is not to maintain ferrets in captivity, but to restore the species to the wild. In 1991, 49 captive-reared ferrets were released in Shirley Basin, north of Medicine Bow, Wyoming. An additional 90 ferrets were released in the same area in 1992, and 48 more were released in 1993. Although it is not known exactly how many of the ferrets have survived, several ferrets produced young in the wild, a sign that the captive breeding and release program can work. More releases will follow.

Using the techniques developed in Shirley Basin, biologists hope to release additional captive-reared ferrets in other suitable
locations throughout the Great Plains. Reintroduction goals call for the establishment of 10 or more separate wild populations of ferrets with a combined total of at least 1500 animals. In South Dakota, the Conata Basin/Badlands area in and around Badlands National Park will probably be the first reintroduction site, and other suitable locations may be evaluated in the near future. Reintroductions of black-footed ferrets could occur in South Dakota by 1994, one more important step toward restoring the species to portions of its natural range.

Glossary


Nocturnal - active at night.
Ecosystem - a complex of plant and animal communities and their environments functioning as a unit in nature.

References


Ashton, D.E. and E.M. Dowd. 1991. Fragile Legacy - Endangered, Threatened and Rare Animals of South Dakota. S.D. Dept. of Game, Fish and Parks, Wildlife Division Report. No. 91-04.
Henderson, F. Robert, Paul F. Springer, and Richard Adrian, 1968. The Black-footed Ferret in South Dakota. SD Department of Game, Fish and Parks, Pierre, SD.
Hygnstrom, Scott E. and Nancy S. Foster. Prairie Dogs and Their Ecosystem. Pamphlet. University of Nebraska-Lincoln, Lincoln, NE.
Linder, Raymond L. and Conrad Hillman, Editors, 1973. Proceedings of the Black-footed Ferret and Prairie Dog Workshop. South Dakota State University, Brookings, SD.
Oakleaf, Bob, et al. Editors, 1992. Black-footed Ferret Reintroduction, Shirley Basin, Wyoming, 1991 Annual Completion Report. Wyoming Game and Fish Department, Cheyenne, WY.
U.S. Fish and Wildlife Service, 1988. Black-footed Ferret Recovery Plan. U.S. Fish and Wildlife Service, Denver, CO.
Wyoming Game and Fish Department, Bureau of Land Management, U.S. Fish and Wildlife Service. Return of a Native. Pamphlet.

Selected Resources For Teachers


Black-footed Ferret , a book by Denise Casey, 1985. Dodd, Mead and Company. New York, NY.
Black-footed Ferret , a video by the National Audubon Society, 666 Pennsylvania Ave SE, Washington, DC. 20003
Black-footed Ferret , Understanding an Endangered Species, Curriculum for Grades 4 - 8, 1994. Badlands National Park, Interior, SD

Written by:
Valerie Naylor, Assistant Chief Naturalist, Badlands National Park, Interior, SD. 57750. 1994.

Illustrated by:
Sophie Cayless, Badlands National Park, Interior, SD 57750.

Reviewed by:
Joseph Zarki, Chief Naturalist, Badlands National Park, Interior, SD 57750.
Bruce Bessken, Chief of Resource Management, Badlands National Park, Interior, SD 57750.
Dr. Erika Tallman, Northern State University, Aberdeen, SD 57401.

Publication of the Black-footed Ferret fact sheet was funded by the South Dakota Department of Game, Fish and Parks, Division of Wildlife, Pierre, SD.