Family: Mustelidae, Weasels view all from this family
Description Mink-like in shape. Yellowish brown or buff above, with brownish wash on back; slightly paler below. Tip of tail and feet dark or black. Dark or black mask around eyes, with face white above and below mask. Male larger than female. L 19 3/4–23” (500–573 mm); T 4 1/2–5 1/2” (114–13” mm); HF 2–2 7/8” (51–73 mm); Wt 18 3/4–22 oz (535–633 g).
Endangered Status The Black-footed Ferret is on the U.S. Endangered Species List. It is classified as endangered throughout its range in Colorado, Kansas, Montana, North Dakota, Nebraska, South Dakota, Utah, and Wyoming. This species is the only wild ferret in existence, and the rarest North American mammal. Its range originally extended as far north as Alaska, but the slaughter of prairie dogs (its primary food) and the destruction of prairie dog towns (the ferret's preferred habitat) has reduced its range considerably and driven the ferret to near extinction. The animal was listed as endangered in 1973, but a surviving population wasn't found until 1981. Those 100-odd ferrets, living in Meeteetse, Wyoming, were nearly wiped out by canine distemper disease, and the remaining ferrets were captured and taken to captive-breeding facilities in 1987. Since then Black-footed Ferrets have been captive-bred and released in the wild, but the prairie dog population remains unstable, and it is not known whether the ferret can ultimately be saved from extinction.
Similar Species Weasels are brown above, white below. Mink is uniformly dark brown to black. Weasels and Mink lack dark mask.
Breeding Mates in spring; implantation is not delayed. 1 litter per year of 3–5 young born late spring– early summer, after gestation of about 41 days. Both sexes sexually mature at 1 year.
Habitat Arid prairies; prairie dog towns.
Range Formerly Great Plains from s Alberta and s Saskatchewan south to w Oklahoma, nw Texas, New Mexico, and nw Arizona. Currently Montana, South Dakota, Wyoming, and Nebraska; scattered populations elsewhere.
Discussion The Black-footed Ferret often lives in prairie dog towns, surrounded by its favorite source of food. It sometimes sits erect, looking for a burrow to raid. A prairie dog that catches sight of it will dart quickly underground. The ferret, keeping its body close to the ground, stalks the prairie dog’s burrow and peers into the entrance. If the prey is near the surface, the ferret lunges for it. Otherwise, it slithers down the tunnel. It quickly kills its prey the way weasels do, with a bite to the base of the skull. After eating, it buries any remains. Having entered its victim’s home, the ferret will sometimes poke its head from the burrow to scan its territory. If it decides to take up residence in the burrow, it enlarges the entrance and builds additional living chambers. When prairie dogs are scarce, the ferret will eat other rodents, including mice, gophers, and ground squirrels, as well as birds, eggs, and small reptiles.
