Prairie dogs make up more than 90% of the black-footed ferret's diet. A ferret may eat more than 100 prairie dogs in one year. Black-footed ferrets are also known to eat ground squirrels, small rodents, rabbits and birds.
A healthy population of black-footed ferrets requires very large groups of prairie dog colonies. Scientists estimate that a healthy population of ferrets requires more than 10,000 acres of prairie dogs to survive long-term. Very few clusters of prairie dogs of this magnitude remain today, which makes even smaller groups important for conservation of the ferret and other species that rely on ecosystems with prairie