Long ago, the black-footed ferret was a common sight on the prairie in the central united states. Due to habitat loss, disease, and a decline in the prairie dog populations (which are the ferret's primary prey), the black-footed ferret was placed on the endangered species list in 1967. In 1974, the black-footed ferret was thought to be extinct. A small population was found in Wyoming in 1981. In 1986, there were only 18 black-footed ferrets alive.