A member of the Mustelidae (weasel) family, the black-footed ferret (Mustela nigripes ) is the only ferret native to North America. It has pale yellow fur, an off-white throat and belly, a dark face, black feet, and a black tail. The black-footed ferret usually grows to a length of 18 in (46 cm) and weighs 1.5–3 lb (0.68–1.4 kg), though the males are larger than the females. These ferrets have short legs and slender bodies, and lope along by placing both front feet on the ground followed by both back feet.
Ferrets live in prairie dog burrows and feed primarily upon prairie dogs , mice, squirrels, and gophers, as well as small rabbits and carrion. Ferrets are nocturnal animals; activity outside the burrow occurs after sunset until about two hours before sunrise. They do not hibernate and remain active all year long.
Breeding takes place once a year, in March or early April, and during the mating season males and females share common burrows. The gestation period lasts approximately six weeks, and the female may have from one to five kits per litter. The adult male does not participate in raising the young. The kits remain in the burrow where they are protected and nursed by their mother until about four weeks of age, usually sometime in July, when she weans them and begins to take them above ground. She either kills a prairie dog and carries it to her kits or moves them into the burrow with the dead animal. During July and early August, she usually relocates her young to new burrows every three or four days, whimpering to encourage them to follow her or dragging them by the nape of their neck. At about eight weeks old the kits begin to play above ground. In late August and early September the mother positions her young in separate burrows, and by mid-September her offspring have left to establish their own territories.
Black-footed ferrets, like other members of the mustelid family, establish their territories by scent marking. They have well developed lateral and anal scent glands. The ferrets mark their territory by either wiggling back and forth while pressing their pelvic scent glands against the ground, or by rubbing their lateral scent glands against shrubs and rocks. Urination is a third form of scent marking. Males establish large territories that may encompass one or more females of the species and exclude all other males. Females establish smaller territories.
Historically, the black-footed ferret was found from Alberta, Canada southward throughout the Great Plains states. The decline of this species began in the 1800s with the settling of the west. Homesteaders moving into the Great Plains converted the prairie into agricultural lands, which led to a decline in the population of prairie dogs. Considering them a nuisance species, ranchers and farmers undertook a campaign to eradicate the prairie dog. The black-footed ferret is dependent upon the prairie dog: it takes 100–150 acres (40–61 ha) of prairie-dog colonies to sustain one adult. Because it takes such a large area to sustain a single adult, one small breeding group of ferrets requires at least 10 mi2 (26 km2) of habitat . As the prairie dog colonies became scattered, the groups were unable to sustain themselves.
In 1954 the National Park Service began capturing black-footed ferrets in an attempt to save them from their endangered status. These animals were released in wildlife sanctuaries that had large prairie dog populations. Black-footed ferrets, however, are highly susceptible to canine distemper, and this disease wiped out the animals the park service had relocated.
In September 1981, scientists located the only known wild population of black-footed ferrets near the town of Meeteetse in northwestern Wyoming. The colony lived in 25 prairie dog towns covering 53 mi2 (137 km2). But in 1985 canine distemper decimated the prairie dog towns around Meeteetse and spread among the ferret population, quickly reducing their numbers. Researchers feared that without immediate action the black-footed ferret would become extinct. The only course of action appeared to be removing them from the wild. If an animal had not been exposed to canine distemper, it could be vaccinated and saved. Some animals from the Meeteetse population did survive in captivity.
There is a breeding program and research facility called the National Black-footed Ferret Conservation Center in Wyoming, and in 1987 the Wyoming Fish and Game Department implemented a plan for preserving the black-footed ferret within the state. Researchers identified habitats where animals bred in captivity could be relocated. The program began with the 18 animals from the wild population located at Meeteetse. In 1987 seven kits were born to this group. The following year 13 female black-footed ferrets had litters and 34 of the kits survived. In 1998 about 330 kits survived. Captive propagation efforts have improved the outlook for the black-footed ferret, and captive populations will continue to be used to reestablish ferrets in the wild. Almost 2,000 black-footed ferrets that were bred and raised in captivity have been released into the wild.
[Debra Glidden ]
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"Black-Footed Ferret." Environmental Encyclopedia. . Encyclopedia.com. (August 20, 2018). http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/black-footed-ferret
"Black-Footed Ferret." Environmental Encyclopedia. . Retrieved August 20, 2018 from Encyclopedia.com: http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/black-footed-ferret
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