Smithsonian National Zoological Park l Friends of the National Zoo



Black-Footed Ferret

(Mustela nigripes)

Black-Footed Ferrets

Home Range

Historically, southern Canada to northern Mexico


Short- and middle-grass prairies


Primarily prairie dogs but also mice and other small rodents


Litters range from one to six young

Social Structure

Solitary except during the breeding season


Black-footed ferrets are endangered. Their small populations in the wild are the result of reintroduction efforts. With the loss of 98 percent of prairie dog habitat, which ferrets depend upon, they neared total extinction in the 1980s. In 1985, only 18 ferrets remained. Thanks to the Wyoming Game and Fish Department, the U.S. Fish and Wildlife Service, the National Zoo's Conservation Research Center (CRC), and other agencies and zoos, ferrets are being bred in captivity and returned to the wild.

Like Giant Pandas?

Ferrets are induced ovulators, which means they do not ovulate until they breed. When CRC staff artificially inseminate them, they give the ferrets a hormone injection the day before to induce ovulation. Ovulation usually results in a pregnancy or a pseudo (false) pregnancy.

As with giant pandas, their hormone levels change as if they were pregnant, whether or not they are. Also, their appetite will increase, they will gain weight, and show other changes in behavior. So staff are not sure which ferrets are pregnant until they give birth or their behavior returns to normal.