First Monday Mustelid brought to you from on the road, as I am currently traveling.

The Black-footed Ferret (Mustela nigripes) is an adorable North American mustelid that seemingly came back from the dead in 1981. Black-footed Ferrets are also known as American polecats and prairie dog hunters, and their population had declined significantly during the 20th century because a severe bought of sylvatic plague had decimated prairie dog populations, depriving the Black-footed Ferret of one of its primary prey items. A Wyoming woman's dog brought a dead Black-footed Ferret to her doorstep in 1981, two years after it had been declared extinct. The U.S. Fish and Wildlife Service launched a breeding program to re-introduce the species in different locations, and while it is still considered to be endangered, over 1,000 healthy animals currently reside in the wild.

Black-footed Ferrets have elongated bodies, broad ears and (of course!) black legs and feet. The rest of their coat is pale/amber in color. Adult males and females are similar in size, though males tend to be slightly larger than females. Males can reach lengths of up to 21 inches (53.3 cm), with another 5 inches (12.7 cm) of tail. They can weigh a little over 3 pounds (1.4 kg) at most. They're most active at night, preferring to catch prairie dogs sleeping in their burrows.


The diet of Black-footed Ferrets of course varies by location, but overall up to 90% of their prey consists of prairie dogs, which are roughly the same weight and length as Black-footed Ferrets themselves. In some areas, like Montana, Colorado, Wyoming and Utah, the variation is driven by necessity since the white-tailed prairie dogs there hibernate four months out of the year. During that time, the Black-footed Ferrets in the area supplement their diet with voles, mice and other rodents.

Because much of what is known about the breeding habits of Black-footed Ferrets has been learned in captive breeding programs, and there are so few of them in the wild, it's difficult to say what their natural reproductive activity is like. Black-footed Ferrets are probably polygynous, and mating occurs in February and March. The kits are born in May and June, about 1 to 5 kits per litter. The birthing dens are co-opted prairie dog dens, no doubt after the original occupants have made for a snack for the expectant females. Kits will reach adult size and independence by October, but won't be sexually mature until they reach one year of age.


The captive breeding efforts that began after the Black-footed Ferrets were discovered to still be extant in 1981 involved both public and private organizations working together. Zoos like the cooperated in the breeding programs, and state and tribal agencies worked with private landowners in reintroduction efforts. The U.S. Fish and Wildlife Service, however, is somewhat in conflict with the U.S. Forest Service, which is tasked with helping landowners control prairie dog populations. Without sufficient prey, Black-footed Ferrets cannot thrive, so this issue continues to be a balance between the interests in the survival of a species, and the impact on ranchers and stock growers.

Source for all images used in this post.