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Biologists sometimes gather information on the overall health of kit foxes Vulpes macrotis by gathering serum chemistry values.
Other common names include: desert fox, zorra del desierto, zorra norteña (Spanish), and wüstenfuchs (German).
Kit foxes have very large ears and excellent hearing. Kit foxes sometimes bark at perceived threats or use a "hacking growl" in intraspecific encounters.
Communication Channels: visual ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Kit foxes are listed as "Least Concern" on the IUCN red list of threatened species. Populations throughout most of the United States are estimated to be stable. San Joaquin kit foxes, V. macrotis mutica, are considered endangered in the United States, as their habitat continues to be fragmented and lost to agriculture. Kit foxes are listed as species of concern in some states, including Colorado and Utah, where programs exist that are designed to protect kit fox populations. They are considered state threatened in California and state endangered in Oregon. In Mexico it is likely that kit fox populations are in decline as 40% of prairie dog populations have been converted to agriculture since 1994. Kit foxes are considered "vulnerable" in Mexico.
US Federal List: endangered
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Kit foxes can have a negative impact on humans by carrying diseases. The main disease of concern is plague, which foxes contract from fleas.
Negative Impacts: injures humans (carries human disease); causes or carries domestic animal disease
Kit foxes are important members of native ecosystems, helping to control rodent populations through predation.
Positive Impacts: research and education; controls pest population
Kit foxes are prey for other carnivores such as coyotes (Canis latrans) and bobcats (Lynx rufus). Also kit foxes are predators of rodents or other small animals, including black-tailed jackrabbits (Lepus californicus), kangaroo rats (Dipodomys), and prairie dogs (Cynomys). Because kit foxes move from den to den in search of a mate and food, their old dens are taken over by other kit foxes or other animals. As scavengers, kit foxes also play a major role in biodegradation.
Fleas, such as Pulex irritans and Pulex simulans, are common parasites of this species. Ticks are also common and include Ixodes texanus and Dermacentor perumapertus. Other cestode parasites include Mesocestoides corti, Mesogyna hypatica, and Dipylidium caninum. Unidentified roundworms and tapeworms have been noted from scat collections.
Ecosystem Impact: creates habitat; biodegradation
Commensal/Parasitic Species:
Kit foxes eat primarily rodents and rabbits. Species preyed on varies regionally, but the most common prey are prairie dogs (Cynomys species), kangaroo rats (Dipodomys species), black-tailed jackrabbits (Lepus californicus), and cottontail rabbits (Sylvilagus species). Kit foxes are primarily carnivores, but if food is scarce, they have been reported to eat tomatoes (Lycopersicon esculentum), cactus fruits (Carnegiea gigantea), and other available fruits. They also will scavenge carrion and eat large insects, lizards, snakes, and ground-dwelling birds.
Kit foxes may compete for food and dens with coyotes (Canis latrans), bobcats (Lynx rufus), red foxes (Vulpes vulpes), and American badgers (Taxidea taxus).
Animal Foods: birds; mammals; reptiles; carrion ; insects
Plant Foods: fruit
Primary Diet: carnivore (Eats terrestrial vertebrates)
Kit foxes are primarily found in the southwestern part of the United States and northern and central Mexico. They are found as far north as the arid interior of Oregon, east to southwestern Colorado, south through Nevada, Utah, southeastern California, Arizona, New Mexico, and into western Texas. In Mexico they are found mainly in the states of Coahuila, Chihuahua, and Nuevo Leon, and throughout Baja California.
Biogeographic Regions: nearctic (Native )
Kit foxes are primarily found in arid regions, such as desert scrub, chaparral, and grasslands. Vegetation communities vary with the regional aridland fauna, but some examples of common habitats are saltbrush Atriplex polycarpa and sagebrush Artemisia tridentata. Kit foxes may also occur in agricultural areas and urban environments. They occur at elevations of 400 to 1900 meters. Kit foxes prefer areas with loose soils for constructing dens. They spend most of their time in dens that they dig themselves or take over from prairie dogs (Cynomys), other rodents, and American badgers (Taxidea taxus). Kit foxes occupy dens year-round and have several dens in their territory that they rotate among. Dens could have one or many entrances and are usually covered by thick brush. They usually stay in their dens during the daytime, exiting to hunt for food at night.
Range elevation: 400 to 1900 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: desert or dune ; savanna or grassland ; chaparral
Other Habitat Features: urban ; agricultural
Vulpes macrotis survival rates are dependent on food availability, reproduction, and local predators. Different studies have estimated different life expectancies for kit foxes. Some report lifespans of 3 to 4 years, while others reported 7 to 12 years. In California a study of 144 kit fox pups showed a 74% mortality rate in pups within the first year.
Range lifespan
Status: wild: 7 (high) years.
Range lifespan
Status: captivity: 12 (high) years.
Average lifespan
Status: wild: 5.5 years.
Kit foxes are the smallest member of the family Canidae in North America. Their most distinctive feature is their exceptionally large ears placed close together on the head. The ears are from 71 to 95 mm in height and they play a role in dissipating heat and the excellent hearing of kit foxes.
Kit foxes range in color from yellowish to gray. They usually have a dark-colored back, light-colored undersides and inner ears, and distinct dark patches on each side of the nose and at the end of the tail. Males average slightly larger than females. Head and body length is from 485 to 520 mm in males (average 537) and from 455 to 535 mm in females (average 501). The tail is from 250 to 340 mm long. Males average 2.29 kg and females 1.9 kg, ranging from 1.6 to 2.7 kg.
Range mass: 1.6 to 2.7 kg.
Range length: 455 to 535 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Predation by coyotes (Canis latrans) accounts for over 75% of kit fox predation. Other predators include bobcats (Lynx rufus), red foxes (Vulpes vulpes), American badgers (Taxidea taxus), feral dogs (Canis lupus familiaris), and large raptors (Accipitridae). Also kit fox deaths have been due to interactions with humans, such as illegal hunting and trapping for fur. Kit foxes are also hit by cars. Kit foxes are wary and nocturnal, with cryptic coloration, reducing their risk of predation.
Known Predators:
Anti-predator Adaptations: cryptic
Most studies have shown kit foxes to be monogamous, with pairs mating for life. Occasional polygyny has also been reported. When the female is ready to reproduce, she goes out on her own in search of a den. This usually happens around the month of September. In October, the male kit fox will join her and remain with her until the end of the breeding season. Female young will sometimes delay dispersal and stay an additional year beyond their independence to help raise their siblings.
Mating System: monogamous ; polygynous ; cooperative breeder
Kit foxes mate once per year from mid-December to February. The typical gestation period is 49 to 55 days, and they can produce a litter of 1 to 7 pups, with an average of 4. Births occus from February to mid-March. Although females are able to breed 10 months after birth, many females do not reproduce that first year. Young females are much lower reproductive success than do older females.
Breeding interval: Kit foxes breed once yearly.
Breeding season: Breeding occurs from December to February.
Range number of offspring: 1 to 7.
Range gestation period: 49 to 55 days.
Average weaning age: 8 weeks.
Range time to independence: 5 to 6 months.
Range age at sexual or reproductive maturity (female): 10 (low) months.
Range age at sexual or reproductive maturity (male): 10 (low) months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Young stay in their birth den until they are 4 weeks old and are weaned at 8 weeks old. The young begin to hunt with their parents at 3 to 4 months old and are independent at 5 to 6 months old. Most young disperse by 8 months old. Both male and female parents care for and protect their young.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Female, Protecting: Male, Female); post-independence association with parents; extended period of juvenile learning
