Kit Fox
These tiny foxes are found on Colorado's western slope.
About This Species
The kit fox is a small mammal of the Southwest desert weighing only about three to six pounds, making them about the size of a full-grown jackrabbit, and the smallest fox in North America. They closely resemble swift foxes found on the eastern plains of Colorado, but have larger ears and a more angular appearance. They have long, black-tipped, bushy tails, dark muzzles and a yellow-gray grizzled coat.
More Information:
Physical Characteristics
The kit fox measures 730 to 840 mm in total length; including a 260 to 323 mm tail, 78 to 94 mm ears, and 113 to 137 mm hindfeet. Adult weight ranges from 1.5 to 2.5 kg. Females are 15 percent lighter on average than males, but there is no other obvious sexual dimorphism. Tail length averages about 40 percent of total body length - a distinguishing trait, along with the large ears, from swift foxes.
The kit fox has a light-colored pelage, variable between grizzled-gray, yellowgray and buff-gray. The shoulders, flanks and chest range from buff to orange. Guard hairs are tipped black or banded. The underfur is lighter buff or white, and relatively heavy and coarse. The legs are slender and thickly furred. The sides of the muzzle are blackish or brownish, and the tip of the tail is black. The soles of the feet are protected by stiff tufts of hair. Because of its relative coarseness, a kit fox pelt has little market value.
Range
In Colorado, kit foxes live in the semi-desert shrub lands extending from Montrose to Grand Junction. The mammals can also be found in Arizona, California, Nevada, New Mexico, western Texas, Utah, southern Oregon and central Mexico.
Habitat
Kit foxes occupy sparsely-covered, semi-desert shrublands of saltbrush, shadscale and greasewood. They spend most of their days in dens that are scattered around the landscape and which are very important for raising young and avoiding predators, such as coyote. Kit foxes generally live in small groups, digging clusters of dens with multiple entrances. The animals move from one den to another and emerge at night to hunt.
Diet
From studies in Colorado examining diets, the fox primarily prey on cottontail rabbits, jackrabbits, white-tailed prairie dogs, rock squirrels and kangaroo rats, but will also eat birds, reptiles, and insects when prey is scarce.
Reproduction
The kit fox is nocturnal and remains in or near its den during the day. Kit foxes use dens year-round. They dig their own, or sometimes adapt badger diggings or prairie dog burrows into dens. Pairs or individuals may use up to 10 dens clustered in a 0.8 to 1.2 ha area. Mating pairs form in the fall or early winter, when each female chooses a whelping den, usually visiting and cleaning out each den within her home range before settling in one.
In Delta and Montrose counties, Colorado, shelter dens studied by Fitzgerald’s team had two entrances and whelping dens had two-four entrances. An average of two to seven entrances is common for shelter dens in other parts of kit fox range. Den entrances are often small and key-hole shaped, which may prevent easy entry by badgers or coyotes. Fewer entrances to dens may indicate the populations of Delta and Montrose Counties are relatively new colonizers.
Breeding season is between December and February, and gestation lasts 49 to 55 days. Litter sizes range from two to six but are typically four or five. Litters are thought to be smaller in Colorado. Pups emerge within four to five weeks and forage with the adults beginning at three to four months of age. In Colorado, pups emerged from dens in May. Family groups remain together until fall, when pups typically disperse beyond their parents’ home range, and adults move to smaller shelter dens. Dispersal distances are not well-studied, although individuals tagged as pups have been recaptured up to 32 kilometers away.
Kit foxes are monoestrous. Young of the year do not breed, and females may take an extra year to reach breeding age compared to males. Some pairs appear monogamous, others seem polygamous, and yet others remain solitary. Based on the occasional overlapping of home ranges, the species does not appear territorial.
Threats to Species
Endangered status: The kit fox is listed as endangered in Colorado, and is considered one of the state's most vulnerable mammal species. Conversion of the kit foxes' native grounds to agriculture and development usage has resulted in a loss of habitat. Predation by coyotes, road-kill, trapping, shooting and predator poisoning are the main causes of mortality for the foxes. Once a furbearer in Colorado, the kit fox has been protected since 1994.
Additional Information
Kit fox hybridize with swift foxes, and some have suggested that kit and swift foxes are conspecific. In Colorado, the southern Rocky Mountains serve as a geographic barrier between swift fox populations to the east and kit foxes to the west. Comparative measurements in Colorado support the distinction between kit fox and swift fox.