The swift fox (Vulpes velox) is a small light orange-tan fox around the size of a domestic cat found in the western grasslands of North America, such as Montana, Colorado, New Mexico, Kansas, Oklahoma and Texas. It also lives in southern Manitoba, Saskatchewan and Alberta in Canada, where it was previously extirpated. It is closely related to the kit fox (V. macrotis) and some mammalogists classify them as conspecific. However, molecular systematics imply that the two species are distinct. Interbreeding between the two species does occur where their ranges overlap (eastern New Mexico and western Texas), but this hybridization is quite restricted in scope.

The swift fox lives primarily in short-grass prairies and deserts. It became nearly extinct in the 1930s as a result of predator control programs, but was successfully reintroduced later. Currently, the conservation status of the species is considered by the IUCN as Least Concern owing to stable populations elsewhere.

Like most canids, the swift fox is an omnivore, and its diet includes grasses and fruits as well as small mammals, carrion, and insects. In the wild, its lifespan is 3 to 6 years, and it breeds once annually, from late December to March, depending on the geographic region. Pups are born anywhere from March to mid-May, and are weaned at six to seven weeks old.