The swift fox (Vulpes velox), once abundant throughout the Great Plains, was distributed from southeastern Alberta southward into the Texas Panhandle and from the Rocky Mountains eastward to the western edge of the tall-grass prairie. They were nearly extirpated from the Plains by 1900. The decline was attributed to predator and rodent control programs involving the use of poisons, trapping, and hunting, and to the destruction of native prairie habitat.
In 1995, the U.S. Fish and Wildlife Service (USFWS) determined that the swift fox warranted protection under the Endangered Species Act and placed the species on the candidate list. However, in the 2001 Annual Candidate Notice of review, the USFWS estimated the swift fox remains in approximately 40% of its range, the species is more abundant and widespread than previously thought and therefore the swift fox was removed from the candidate list.
Physical characteristics of swift foxes include its small size (12-12.5 inches in height; 31 inches in total length; 5.0-5.4 pounds in weight), large ears, black muzzle patches, buffy tan coloration and black-tipped tail. It is the smallest of the canid species. Swift fox are primarily nocturnal, highly fossorial (i.e. closely associated with underground den sites), and very fast.
Swift fox are considered an opportunistic predator. They feed on small mammals, insects, reptiles, carrion, and ground nesting birds. Small mammals are especially important, particularly in winter months.
Habitat characteristics of swift fox vary but are generally characterized as flat to gently rolling short and mixed grass prairies. However, swift fox have also been documented inhabiting areas with a mixture of agricultural cropland and prairie grassland and are even considered abundant in the cultivated cropfields of Kansas.
All of South Dakota was historically considered as part of the range of the swift fox. The swift fox remains listed as state threatened in South Dakota. Swift fox are considered extirpated from the Lower Brule Sioux Reservation.