[5] 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.

[2] 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.

[7] The swift fox was once a severely endangered species, due to predator control programs in the 1930s that were aimed mostly at the gray wolf and the coyote.

[8] The species was extirpated from Canada by 1938,[2] but a reintroduction program started in 1983[9] has been successful in establishing small populations in southeast Alberta and southwest Saskatchewan, despite the fact that many reintroduced individuals do not survive their first year.

[8] Nonetheless, by 1996, 540 foxes had been released around the Alberta-Saskatchewan border and Milk River Ridge areas, parts of the species' original native range.

Daytime activities are usually confined to the den, but it has been known to spend the warm midday period above ground during the winter.

[8] Due to the harsh winter conditions where the swift fox can be found, there is an increase in mortality rates.

[14] The swift fox is more heavily dependent on its den than most North American canids, using them as shelter from predators.

A newborn pup's eyes and ears remain closed for ten to fifteen days, leaving it dependent on the mother for food and protection during this time.

[8] Recent research has shown that social organization in the swift fox is unusual among canids, since it is based on the females.

Rabbits, mice, ground squirrels, birds, insects, other arthropods, lizards, amphibians, fish and eggs are staples.

[8] During the summer, adults eat large amounts of insects, including beetles and grasshoppers, and feed their young with larger prey items.