Kit fox

The kit fox (Vulpes macrotis) is a small fox found in the dry and semi-dry landscapes of the Southwestern United States, as well as northern and central Mexico. It is the smallest of the four fox species in the genus Vulpes native to North America and ranks among the smallest vulpines globally. Its oversized ears, which help with heat dissipation and hearing, have earned it comparisons to the fennec fox.

**Taxonomy** Some mammalogists consider the kit fox the same species as the swift fox (V. velox), but molecular studies show they are distinct. Where their ranges meet in eastern New Mexico and western Texas, the two species occasionally interbreed, though this hybridization is very limited. Subspecies classifications remain unresolved. While up to eight subspecies have been proposed, further research has not supported most of them. However, evidence suggests that kit foxes in California’s San Joaquin Valley, isolated geographically, likely deserve their own subspecies designation (V. m. mutica), with all other kit foxes possibly grouped under V. m. macrotis.

**Subspecies** The San Joaquin kit fox (Vulpes macrotis mutica) was once abundant across central California and the San Joaquin Valley. By 1990, its population was estimated at 7,000. Despite being listed as endangered on March 3, 1967—nearly 50 years ago—it remains endangered. On September 26, 2007, Wildlands Inc. established the 684-acre Deadman Creek Conservation Bank specifically to protect its habitat. Still, the subspecies continues to decline, mainly due to severe habitat loss. Additional threats include competition from red foxes and the extirpation of wolves from California, which has made the coyote the dominant meso-predator in kit fox territory, disrupting the ecosystem balance.

**Appearance** The kit fox is one of North America’s smallest canids. Males are slightly larger than females, but sexual dimorphism is minimal. Average weight ranges from 1.6 to 2.7 kg (3.5–6.0 lb). Body length is 455–535 mm (17.9–21.1 in), with a long tail (about 40% of total length) adding 260–323 mm (10.2–12.7 in). Its large ears, measuring 71–95 mm (2.8–3.7 in), aid in heat regulation and provide exceptional hearing. Coat color and texture vary by region. Typically, the back is grizzled or yellowish-gray, created by guard hairs that are black-tipped or have two black bands separated by a white band. These hairs are under 50 mm (2.0 in) long and are most prominent along the middle of the back. The soles of the feet have stiff hair tufts for traction on loose sand and protection from extreme temperatures. The muzzle and vibrissae are usually black to brown. The bushy, gray tail ends in a black tip, and the caudal gland has a distinct black spot. Unlike the gray fox, there is no stripe along the tail. Color ranges from yellow to gray, with a darker back and lighter belly and inner ears. Dark patches surround the nose. The ears are tan or gray on the back, turning buff or orange at the base. The shoulders, lower sides, flanks, and a 25 mm (1 in) strip across the chest range from buffy to orange.

**Distribution and habitat** The kit fox’s northernmost range is the arid interior of Oregon, with its eastern limit in southwestern Colorado. It is found south through Nevada, Utah, southeastern California, Arizona, New Mexico, and into western Texas. It lives in arid and semi-arid habitats such as desert scrub, chaparral, halophytic areas, and grasslands, favoring places with sparse ground cover. Vegetation varies by region, including sagebrush (Artemisia tridentata) and saltbrush (Atriplex polycarpa). Loose-textured soils are often chosen for denning. Kit foxes also occur in agricultural areas, particularly orchards, and occasionally in urban settings. They are found at elevations from 400 to 1,900 meters (1,300–6,200 ft).

**Behavior** Kit foxes are mostly nocturnal, sometimes active at dawn and dusk, and avoid daytime heat by resting in underground dens. They usually forage alone. They are not strongly territorial, often living in pairs or small family groups. Dens are used year-round for daytime rest, escaping predators, avoiding extreme temperatures, conserving moisture, and raising young. Kit foxes dig their own dens or modify burrows made by badgers, ground squirrels, prairie dogs, and kangaroo rats. Dens are scattered across their home range, and an individual typically uses more than 11 dens each year. They normally rest in dens during the day but may emerge to bask or, when pups are young, to play. Unlike many canids that pant only at the resonant frequency of the thorax, kit foxes pant at a rate that increases with ambient temperature until it exceeds that frequency, trading energy for water conservation. Their apparent speed is partly an illusion of their small size and cryptic coloration, combined with a remarkable ability to dodge and change direction. One recorded account clocked a kit fox at about 40 km/h in front of a car.