The Black Footed Ferret is considered the most endangered animal in North America. In the past, Black Footed Ferrets lived from Southern Canada to Northern Mexico, in areas where prairie dog colonies existed. Loss of habitat, disease and mass poisoning of prairie dogs (their main food source) led to their near extinction. Ranchers poison Prairie Dogs because they eat grass that the ranchers want reserved for use as cattle feed.
Between 1986 and 1987, in an effort to save the species from extinction, the last of the 18 Black Footed Ferrets were captured from the wild. The 18 were placed into captive breeding programs to save the species. In 1988, the Black Footed Ferret Recovery Plan was introduced by the US Fish and Wildlife Service. The Black Footed Ferret Recovery Plan set in place a breeding program where the ferrets would be separated into different locations to avoid the possibility of an illness wiping out the whole species. The program also started the Black Footed Ferret Genome Resource Bank, where sperm is collected from male ferrets for future breeding. The sperm can be collected and sent to other breeding programs to increase genetic diversity, which avoids the problem of relocating ferrets for the breeding program.
Though Black Footed Ferrets are still endangered, captive breeding programs have shown some success. The ferrets are regularly being reintroduced into the wild and in some areas they have started to breed in the wild. The IUCN estimates that there are now 1,000 Black Footed Ferrets in the wild and 300 in captivity, and they predict the numbers will increase.
Although the growth of the species shows hope for their survival, they are far from being out of danger. They still face many of the same threats in the wild that they did in the past. Habitat loss due to grasslands being converted for agricultural use, is a huge problem. Low numbers of the Prairie Dog species (the Black Footed Ferrets main food source) in the wild, may pose a significant problem.
Lack of genetic diversity may cause weak immune systems in Black Footed Ferrets. Even though captive breeding programs have made every possible attempt to provide genetic diversity, the limited original number of the captured wild ferrets could only provide limited genetic materials. Black Footed Ferrets are susceptible to the Sylvatic Plague and Canine Distemper. Both diseases are deadly to the species.