Other names: Pispiza itopta sapa, black-faced prairie dog, the American ferret, Putorius nigripes
Identification: Fur is buff/tan on the body with some black-tipped hairs along the back, lighter color on the underside. Black feet and legs, face mask and tail tip. Fur length approximately 0.4 inches (1 cm). Body length of adult and juvenile females in autumn 14 ½ - 17 inches (35-43 cm) averaging 15 ½ inches (39 ½ cm) plus a 4 ½ inch (12 cm) tail. Average female weight in autumn is 1.6 lbs. (730 g). Males larger than females with adult males measuring 16-17 ½ inches (41-45 cm) long, averaging 17 inches (43.2 cm) plus a 5 inch (13 cm) tail in autumn. Average adult male weight in autumn is 2.4 lbs. (1,095 g). Juvenile males measure 14 ½ - 18 inches (37-45 ½ cm) long, averaging 16 ½ inches (41.8 cm) in autumn plus a 5 inch (13 cm) tail. Juvenile male weight in autumn averages 2 lbs. (933 g).
Habitat: Black-tailed prairie dog colonies, white-tailed prairie dog colonies, Gunnison’s prairie dog colonies. Black-footed ferrets are found surviving only on prairie dog colonies.
Food: Prairie dogs make up more than 90% of their diet. The remaining portion is comprised of mice, voles, rabbits and small birds. Predation upon prairie dogs takes place below ground at night typically while prairie dogs are sleeping. Occasionally black-footed ferret use ambush hunting techniques near sunrise to capture a prairie dog as it emerges from the burrow.
Reproduction: Breeding season begins in late March and continues through April. Territorial males will breed as many females as possible. Black-footed ferrets are induced ovulators. Gestation is 44 days and kits are born below ground completely altricial (blind, naked, helpless). Average litter size is 3 (range 1-6). Female nurses the kits until they emerge above ground for the first time, usually in July. After copulation the male has no role in raising the young. Kits are adult size by autumn and ready to breed at 10 months of age.
Behavior: Black-footed ferrets are territorial and solitary with the exception of breeding season and litter rearing. Male home ranges average 132 acres (53 hectares) and generally overlap female home ranges that average 65 acres (26 hectares). Kits are adult sized by September (females) and November (males) and will disperse away from their mothers in September. Males typically disperse farther than females and also experience a higher mortality rate. Survival to 1 year is approximately 30% for males and 50% for females. Primary predators of black-footed ferrets include coyotes, badgers and great horned owls.
Black-footed ferrets are mostly nocturnal but occasionally are seen in the daylight. At night they bound between prairie dog burrows. Active year-round they leave a distinctive track in the snow that biologists can track. Frequently carry ticks (on the neck and head) and fleas (throughout the body but particularly the rump). Fleas are a vector of plague which is fatal to black-footed ferrets. Also susceptible to canine distemper.
Conservation status: Listed as endangered under the Endangered Species Act in the US and Mexico. Listed as extirpated in Canada under the Species at Risk Act (SARA). Prairie dog poisoning, land conversion to agriculture and plague reduced and fragmented prairie dog populations throughout the 20th Century. The first population ever studied was in Mellette County, South Dakota 1964-1974. Nine individuals captured for captive breeding but no live young were produced. The last captive black-footed ferret from Mellette County died in 1979 and the wild population was also gone. Biologists feared the species was extinct.
On September 26, 1981 a ranch dog near Meeteetse, Wyoming killed a black-footed ferret and brought it home to John and Lucille Hogg who took it into to taxidermist Larry LaFranchie who identified it as a black-footed ferret. A population was discovered and studied on white-tailed prairie dog colonies occupying private lands near Meeteetse. The population peaked at 129 individuals in 1984 but declined to 58 in 1985. Sylvatic plague and canine distemper were decimating the population and eventually the decision was made to capture some animals. Six were captured but died of canine distemper. The remaining wild black-footed ferrets were captured in the Fall of 1985 and Fall/Winter of 1986-87. A total of 18 were removed (11 females, 7 males) and formed the nucleus of a successful captive breeding program. By 1991 enough kits were produced in captivity that reintroductions back into the wild began and continue today. Black-footed ferrets have been reintroduced at 19 locations in 8 US States, Mexico and Canada. Future recovery of the species is completely dependent upon managing healthy prairie dog populations, requiring tools to mitigate plague and overcoming the negative social attitudes towards prairie dogs from the agricultural community.
Prairie Wildlife Research is a 501(c)3 non-profit organization dedicated to the preservation of prairie species - especially the endangered black-footed ferret. PO Box 308 Wellington, CO 80549 970.219.1659 email@example.com