Threatened and Endangered Species Black-Footed Ferret Fact Sheet
Threatened and Endangered Species: Black-Footed Ferret Mustela nigripes
OFFICIAL STATUS: Endangered. Endangered species are species that are in danger
of extinction throughout all or a significant portion of their range. It is
unlawful to kill, harm, or harass endangered species.
LISTED: 35 Federal Register 8495; June 2, 1970.
HISTORICAL STATUS: Black-footed ferrets once ranged throughout the Great Plains.
Populations declined dramatically in the 1980’s. The last known population was
found at Meeteetse, Wyoming, in 1981. The remaining 18 individuals from this
population were captured and put into a captive breeding facility in 1987.
PRESENT STATUS: From 1987 until 1991 the black-footed ferret may have been
extirpated in the wild. In the fall of 1991, 49 captive animals were
reintroduced into the wild in Wyoming. The reintroduced animals were designated
an “experimental” population. Additional ferrets have been introduced each year
since 1991. Unconfirmed sightings from other areas continue to be reported.
There are still about 400 black-footed ferrets in captivity. In Montana, parts
of Phillips County are targeted for ferret reintroduction.
HABITAT: The black-footed ferret inhabits short grass prairies, always within
close proximity to prairie dog towns.
LIFE HISTORY: Black-footed ferrets can breed when 1 year old. Breeding takes
place from March to May. Gestation ranges from 41 to 45 days. Typically, there
are 3 to 4 young per litter. Young ferrets leave the family group around
September. Juvenile males suffer high mortality, a result of their dispersing to
new areas. Life expectancies for wild black-footed ferrets are probably less
than 5 years.
Prairie dogs comprise 90 percent of the diet of black-footed ferrets. A ferret
family of 4 will consume an average 763 prairie dogs per year. These animals
utilize prairie dog burrows for shelter and raising families. Black-footed
ferrets are primarily nocturnal. They are active in winter.
AID TO IDENTIFICATION: Black-footed ferrets are 20 inches to 24 inches long,
including a 6 inch tail, and weigh up to 2-1/2 pounds. They have a yellowish
brown body with a distinctive black mask across the face, black on the feet and
the tip of the tail. The related long-tailed weasel is about half the size of
the ferret and does not have the distinctive black markings.
REASONS FOR DECLINE: The rapid decline of black-footed ferrets has been linked
to the eradication of prairie dogs. Prairie dogs now occupy less than 1 percent
of their historic range. Canine distemper also can threaten ferret populations.
RECOMMENDATIONS: It is recommended that individuals contact the U.S. Fish and
Wildlife Service before initiating activities that affect prairie dog towns.
Report any suspected black-footed ferret sightings to a wildlife agency.
COMMENTS: Prairie dogs are essential to black-footed ferrets. Dog towns provide
habitat for other rare species such as mountain plovers, burrowing owls,
ferruginous hawks, prairie falcons, swift fox, and game species like antelope.
REFERENCES: Black-footed Ferret Recovery Plan by U.S. Fish and Wildlife Service,
1988. Handbook of Methods for Locating Black-footed Ferrets 1984, and
Black-footed Ferret Habitat: Some Management and Reintroduction Considerations
1985, both published by the Wyoming Game and Fish Commission and the U.S. Bureau
of Land Management.
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