Friday, February 26, 2021

Gemini Foxes: The Kit Fox and Swift Fox

Santa Cruz Island fox

In the first installment of Foxes of North America we introduced you to the beautiful and intelligent red fox, a fox that prefers to live on the edge and is very different from the island fox.

Here we'll take a quick look at the kit and swift foxes. Don't be fooled by their general appearance–they are not island foxes.

According to J. David Henry in his book Foxes: Living on the Edge, "The kit fox and the swift fox are the Gemini foxes of North America," because they share many physiological and morphological similarities. Kit and swift foxes inhabit the arid regions of North America and are adapted to habitats with relatively open vegetation.


Kit Fox, photo courtesy of CA Fish & Wildlife

Kit Fox

Kit foxes are native to the desert and semi-arid shrublands and grasslands of the southwestern US, including parts of Oregon, Colorado, and northwestern Mexico. They are a small fox species with a slender appearance, 5 pounds on average. Their coat is grizzled to tawny gray with buffy highlights on the neck, sides and legs. Their face has a typical "foxy" appearance, except for their ears, which are much longer than those of any other North American canid. This adaptation may help them dissipate body heat in the desert and could help them hunt insects and mice. To protect their feet from the hot sands, kit foxes have considerable hair between the pads, forming a kind of "sand shoe." Kit foxes are often confused with gray foxes because their ranges overlap, but kit foxes can be distinguished by the lack of a black ridge running the length of the tail as well as by their large ears.

The scientific name is Vulpes macrotis, which translates to "big eared fox."

San Joaquin Kit Fox, photo courtesy Tory Westall, ESRP - CSU Stanislaus

Kit foxes are opportunistic foragers that rely heavily on rodents and insects for sustenance. Kangaroo rats, pocket mice, and ground squirrels are common rodent prey. Like island foxes, kit foxes also consume beetles and grasshoppers. Kit foxes are also known to consume rabbits, birds, reptiles, and a variety of non-insect invertebrates

A unique feature of both the kit fox and the swift fox is the continuous use of underground dens throughout the year. Other canid species, including the island fox, use underground dens only during pup season. The Gemini Foxes clump their dens in suitable habitat and use them to provide critical protection from predators and shelter from extreme temperatures in desert summers and northern winters.

The San Joaquin subspecies of kit fox (V. macrotis mutica), which is restricted to the San Joaquin Valley and adjacent valleys in California, is currently listed as endangered under the Endangered Species Act. The kit fox is also listed as endangered by the State of Colorado and as threatened by the State of Oregon. The most serious threats include habitat loss and declining habitat suitability due to invasion of non-native grasses.

Swift Fox, photo courtesy K. Schafer

Swift Fox

Swift foxes primarily occur in the short and mixed-grass prairies from New Mexico and Texas north to southern Canada. Similar in size and appearance to the kit fox, the swift fox is pale yellowish-red and grey, with a thick grey stripe down its back that extends to its black-tipped tail. Its underside is lighter in color, and it has black patches on either side of its muzzle. You can distinguish swift foxes from kit foxes by the swift fox's smaller and rounder ears. Also, the swift fox's tail is shorter in relation to its body size than that of the kit fox.

Their scientific name is Vulpes velox, which simply translates to "swift fox."


Swift Fox, photo courtesy Gordon Court

Swift foxes are resourceful foragers, with a varied diet that includes small mammals, such as prairie dogs, birds, insects, plants and carrion. To reduce risk of predation by coyotes, swift foxes avoid areas with high prey density, such as areas of high plant diversity. They prefer open habitat where visibility is greatest.

Once abundant throughout their range, swift fox populations began to decline in the late 1800s due to rodent and predator control programs and the plowing of prairie into cultivated crop fields. As a result, the species is currently recognized as a species of conservation concern over much of its range. In Canada, the swift fox was gone or extripated by the 1930s. However, in 1983, a privately run program began breeding swift foxes in captivity in the US so that they could eventually be reintroduced back into the wild in Canada. Experts from this captive breeding effort provided advice for the captive breeding of island foxes in the early 2000s. While swift foxes are still classified as endangered, the swift fox's return is one of the most successful species reintroduction stories in Canada, just as the island fox's recovery is hailed as a success in the US.

Coming up next is the Fox of the Tundra: Arctic Fox

Series installments:

How is the Island Fox Unique?

Red Fox: Life on the Edge

Arctic Fox: Fox of the Tundra

The Island Fox's Origin - The Gray Fox

For additional information on the San Joaquin Kit fox visit:


Butler, Andrew R., Kristy L.S. Bly, Heather Harris, Robert M. Inman, Axel Moehrenschlager, Donelle Schwaim, and David S. Jachowski. May 22, 2020. "Home range size and resource us by swift foxes in northeastern Montana." Journal of Mammalogy, vol. 101, (3), pg 684–696. Accessed at:

Cyper, B.L. 2003. "Foxes (Vulpes species, Urocyon species and Alopex lagopus)." In Wild Mammals of North America: Biology, Management, and Conservation, 2nd edition by G. Feldhamer, B. Thompson, and J. Chapman (eds), pg 511–546. Baltimore: Johns Hopkins University Press.

Elbroch, M. and K. Rinehart. 2001. Behavior of North American Mammals. pg 94–100. Peterson Reference Guides.

Harris, Heather (ed). July 2020. Swift Fox Conservation Team Report for 2017–2018. Montana: Montana Fish, Wildlife & Parks Glasgow.

Henry, J. D. 1996. Living on the Edge, Foxes. Minocqua, WI: Northword Press. 

Kelly, Erica C., Brian L. Cypher, and David J. Gemano. 2019. "Temporal variation in foraging patterns of Desert Kit Foxes (Vulpes macrotis arsipus) in the Mojave Desert, California, USA." Journal of Arid Environments, vol 167, pg 1–7. ISSN 0140-1963.

Meaney, C.A., M. Reed-Eckert, and G.P. Beauvais. August 21, 2006. Kit Fox (Vulpes macrotis): a technical conservation assessment. USDA Forest Service, Rocky Mountain Region. Accessed at: