Disease: Another critical factor contributing to the endangerment of Black-footed ferrets was disease transmission from domestic ferrets and other carnivores. Distemper, canine hepatitis, and rabies are among the diseases that proved deadly to black-footed ferrets, further reducing their already dwindling populations.
Small Population Size and Genetic Diversity: Black-footed ferrets have naturally small population sizes, making them more susceptible to the impacts of habitat loss and disease. In addition, their limited genetic diversity increased the risk of inbreeding and reduced the species' ability to adapt to changing environmental conditions.
Predation: With reduced habitat and decreased population numbers, black-footed ferrets became more vulnerable to predation from larger predators such as coyotes and badgers. This further added to the decline of their populations.
Due to these combined factors, the Black-footed ferret population declined to the point of near extinction in the wild by the mid-20th century. Conservation efforts, including captive breeding programs and reintroductions, have helped to bring the species back from the brink, but they remain critically endangered and face ongoing challenges to their survival.