The endangered black-footed ferret is a member of the weasel family. It is the only ferret native to North America – the domestic ferret is a different species of European origin and has been domesticated for hundreds of years – and has a tan body with black legs and feet, a black tip on the tail and a black mask. It has short legs with large front paws and claws developed for digging. Its large skull and strong jaw and teeth are adapted for eating meat.
Height: 6 inches.
Length: 18-24 inches (including a 5-6 inch tail).
Weight: 1.5-2.5 lbs; males slightly larger than females.
Lifespan 3-4 years in the wild; 8-9 years in captivity.
Prairie dogs make up 90% of a black-footed ferret’s diet. A ferret may eat over 100 prairie dogs in one year. Black-footed ferrets are also known to eat ground squirrels, small rodents, rabbits and bird
Black-footed ferrets once numbered in the tens of thousands, but widespread destruction of their habitat and exotic diseases in the 1900s brought them to the brink of extinction. Only 18 remained in 1986. Today, they are making a comeback, with approximately 750 black-footed ferrets in the wild, and another 250 living in captive breeding facilities (2008).
Black-footed ferrets were once found on black-tailed prairie dog colonies across the Great Plains from southern Canada to northern Mexico, and on white-tailed and Gunnison’s prairie dog colonies across the intermountain west. By 1986 they were completely gone from the wild. Today, they have been reintroduced to 15 locations within their former range in Wyoming, South Dakota, Montana, Arizona, Colorado, Utah, Kansas and Chihuahua, Mexico (2008)
Black-footed ferrets eat, sleep and raise their young in prairie dog burrows, and spend about 90% of their time underground. They sleep during the day and hunt prairie dogs at night.
A healthy population of black-footed ferrets requires very large prairie dog colonies. Scientists estimate that more than 10,000 acres of prairie dog colonies are required, and results from the various reintroduction sites show that it may actually take more than 20,000 acres.
Mating Season: March-April.
Gestation: 41-43 days. Kits are born in May-June.
Litter size: 3-4 kits average; ranges from 1-7 kits.
Kits are born blind and helpless and stay below ground until they are about 2 months old. At this age, the female begins to take her young on hunting forays and separates the kits into different burrows. By October, the young are completely independent and will disperse to their own territories.
Because black-footed ferrets live in prairie dog burrows and eat prairie dogs, they are completely dependent upon large prairie dog colonies for survival. But prairie dog colonies have been reduced to less than 5% of the area they originally occupied due to habitat destruction, poisoning, shooting, and exotic disease (sylvatic plague). The remaining prairie dog colonies are small and fragmented, often separated by great distances. Prairie dog colony losses continue today due to all of these threats, and with the loss of prairie dogs comes the loss of black-footed ferrets.
Climate change could affect prairie dog habitat as well by increasing the intensity and duration of droughts, which reduce the availability of the grassland plants they need for food, and can increase the frequency of fires and the threat of invasive species.
Thanks to the protection of the Endangered Species Act, America’s investment of over $30 million since 1981 and the hard work of many federal, tribal and state biologists, zoos and private landowners there are now (as of May 2008) at least 750 ferrets living in the wild in 15 locations across the West.
By 2010 biologists hope to have 1,500 ferrets established in the wild, with no fewer than 30 breeding adults in each population. If these objectives are met, the ferret could be downlisted from endangered to threatened status. But to be truly successful, ferrets will need several reintroduction sites, each with more than 10,000 acres of prairie dog colonies, and such areas are few. Until more large prairie dog colonies are restored, the ferret cannot be fully recovered
Endangered Species Act (ESA): Almost all populations of black-footed ferrets except those listed as non-essential experimental populations are listed as endangered under the Endangered Species Act