The black-footed ferret is an endangered species that historically ranged across prairie grasslands in North America. Its range and numbers declined dramatically due to habitat loss, poisoning of prairie dogs which are its primary food source, and diseases. Restoration efforts since the 1980s have established over 2,300 ferrets across 15 reintroduction sites through a captive breeding program, but the species remains endangered and dependent on the conservation of sufficient prairie dog habitat.