Black-footed ferret

Black-footed Ferret
	File:Ferret USFWS.jpg
	Mustela nigripes
Conservation status
	; Critically Imperiled (NatureServe)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Family:	Mustelidae
Genus:	Mustela
Species:	M. nigripes
Binomial name
	Mustela nigripes; (Audubon & Bachman, 1851)

The Black-footed Ferret (Mustela nigripes) is a small carnivorous North American mammal closely related to the Steppe Polecat of Russia, and a member of the diverse family Mustelidae which also includes weasels, mink, polecats, martens, otters, and badgers. It should not be confused with the domesticated ferret.

The Black-footed Ferret is an endangered mammal in North America, according to the U. S. Fish and Wildlife Service (USFWS). They became extirpated in the wild in Canada in 1937, and were classified as endangered in the U.S. in 1967. The last known wild population was taken into captivity in the mid-1980s, a few years after its accidental discovery in Wyoming. Release of captive animals has successfully re-introduced the species to parts of its former habitat, and currently these populations have made what has been called an "astonishing comeback".^[1]^[2]

Physical description

Black-footed Ferrets are about 45 cm (18 in) long, with a furry 15-cm (6 in) tail, and they weigh roughly 1 kg (2 lbs). Like most members of the family, they are very low to the ground with an elongated body and very short legs. Their fur is white at the base but darkens at the tips, making them appear yellowish-brown overall, with black feet and tail-tip, and a distinctive black face mask. These blend in well with the prairie ecosystem in which they live.

Ecology and behavior

They are nocturnal hunters that require a plentiful supply of prairie dogs for prey. Though they will also eat other small mammals, birds, and insects, a single family of four Black-footed Ferrets eats about 250 prairie dogs each year and cannot survive without access to large colonies of them. Typically a prairie dog colony 125 acres (50 ha) in size will provide a sufficiently stable prey population for one adult ferret. The ferrets are entirely dependent on the prairie dogs for their survival, and even shelter in prairie dog burrows during the day.

Conservation status

The loss of their prairie grassland habitat, the drastic reduction of prairie dog numbers (through both habitat loss and poisoning), and the effects of canine distemper and sylvatic plague (similar to bubonic plague) have all contributed to the near-extinction of the species during the 19th and 20th centuries. Even before their numbers declined, Black-footed Ferrets were rarely seen: they weren't officially recognized as a species by scientists until 1851, following publication of a book by naturalist John James Audubon and Rev. John Bachman. Even then, their existence was questioned since no other Black-footed Ferrets were reported for over twenty years.

In 1981, a very small population of about 130 animals was discovered near Meeteetse, Wyoming. Soon after discovery, the population began a rapid decline due to disease. By 1986, the Wyoming Game and Fish Department led a cooperative program to capture the 18 remaining animals and begin an intensive captive breeding program. At that time, the entire world population amounted to about 50 individuals in captivity.

U.S. federal and state agencies in cooperation with private landowners, conservation groups, Native Americans, and North American zoos, have been actively reintroducing ferrets back into the wild since 1991. Beginning in Wyoming, reintroduction efforts have since expanded to sites in Montana, South Dakota, Arizona, Utah, Colorado and Chihuahua, Mexico. Proposed reintroduction sites have been identified in Canada. However, in May 2000, the Canadian Species at Risk Act listed the black-footed ferret as being an extirpated species in Canada.^[3]

As of 2007, the total wild population of black-footed ferrets numbers well over 600 in the United States. While the IUCN formally classifies them as extinct in the wild, this is due to the last update to the redlist assessment having been in 1996 when the species was indeed only surviving in captivity (Mustelid Specialist Group, 1996). The Black-footed Ferret is listed as "Endangered" under the Endangered Species Act since September 20, 2005. An April 2006 report in the New York Times puts South Dakota's Conata Basin populaiton at arond 250. Arizona's Aubrey Valley populaiton is well over 100 and they have started a second reintroduciton site using around 50 animals. An August 2007 report by Wyoming researchers in the journal Science counted a population of 223 in one area of the state (the original number of re-introduced ferrets, most of which died, was 228), and an annual growth rate of 35% from 2003–2006 was estimated.^[1] This rate of recovery has been said to be much faster than for many endangered species, and the ferret seems to have prevailed over the previous problems of disease and prey shortage that hampered its improvement.^[2]

The recovery plan calls for the establishment of 10 or more separate, self-sustaining wild populations. Biologists hope to have 1500 Black-footed Ferrets established in the wild by the year 2010, with at least 30 breeding adults in each population. Meeting this objective would allow the conservation status of the species to be downgraded to threatened.