View source for Kit fox

{{Short description|Species of fox native to North America}}
{{about|the fox species|young foxes of any species|fox}}
{{Speciesbox
| name = Kit fox
| image = Vulpes macrotis mutica sitting.jpg
| image_caption = [[San Joaquin kit fox]] sitting
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 19 November 2021">{{cite iucn |author=Cypher, B. |author2=List, R. |date=2014 |title=''Vulpes macrotis'' |volume=2014 |page=e.T41587A62259374 |doi=10.2305/IUCN.UK.2014-3.RLTS.T41587A62259374.en |access-date=19 November 2021}}</ref>
| genus = Vulpes
| species = macrotis<ref name=msw3>{{MSW3 Wozencraft | id = 14000878}}</ref>
| authority = [[Clinton Hart Merriam|Merriam]], 1888
| synonyms =
{{Species list
| Vulpes muticus | Merriam, 1902
| Vulpes neomexicanus | Merriam, 1903
| Vulpes arsipus | [[Daniel Giraud Elliot|Elliot]], 1904
| Vulpes devius | [[Edward William Nelson|Nelson]] and [[Edward Alphonso Goldman|Goldman]], 1909
| Vulpes arizonensis | Goldman, 1931
| Vulpes nevadensis | Goldman, 1931
| Vulpes tenuirostris | Nelson and Goldman, 1931
| Vulpes zinseri | Benson, 1938
}}
| synonyms_ref = <ref name=msw3 />
| range_map = Kit Fox area.png
| range_map_caption = {{legend0|#865324|&nbsp;distribution}}
| subdivision_ranks = Subspecies
| subdivision =
:''V. m. macrotis''
:''[[San Joaquin kit fox|V. m. mutica]]''
}}
The '''kit fox''' ('''''Vulpes macrotis''''') is a fox species that inhabits arid and semi-arid regions of the southwestern United States and northern and central Mexico. These foxes are the smallest of the four species of ''Vulpes'' occurring in North America and are among the smallest of the vulpines worldwide. It has also been called a North American counterpart of the [[fennec fox]] due to its large ears.<ref name="Sheldon1992"/>
==Taxonomy==
Some mammalogists classify it as conspecific with the [[swift fox]], ''V. velox'',<ref name="Dragoo"/> but [[molecular systematics]] indicate that the two species are distinct.<ref name="MercureRalls1993">{{cite journal|last1=Mercure|first1=Alan|last2=Ralls|first2=Katherine|last3=Koepfli|first3=Klaus P.|last4=Wayne|first4=Robert K.|title=Genetic Subdivisions among Small Canids: Mitochondrial DNA Differentiation of Swift, Kit, and Arctic Foxes|journal=Evolution|volume=47|issue=5|year=1993|pages=1313–1328|issn=0014-3820|doi=10.2307/2410150 |pmid=28564903|url=https://www.researchgate.net/publication/271806502|jstor=2410150}}</ref>
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.<ref name="Sheldon1992">{{cite book |last1=Sheldon |first1=Jennifer W. |title=Wild dogs: the natural history of the non-domestic Canidae |date=1992 |publisher=Academic Press |location=San Diego |isbn=9781483263694 |pages=176–182}}</ref>
Subspecific designations for the species are not fully addressed. As many as eight subspecies have been recognized,<ref name="McGrew1979"/> although further analyzes have not found support for any subspecies differentiation.<ref name="Dragoo">{{cite journal |last1=Dragoo |first1=J. W. |last2=Choate |first2=J. R. |last3=Yates |first3=T. L. |last4=O'Farrell |first4=T. P. |title=Evolutionary and Taxonomic Relationships among North American Arid-Land Foxes |journal=Journal of Mammalogy |date=28 August 1990 |volume=71 |issue=3 |pages=318–332 |doi=10.2307/1381942|jstor=1381942 }}</ref> However, although there is a clear need for more subspecific clarification, most available data suggest that kit foxes in the [[San Joaquin Valley]] of California are likely to warrant a subspecific designation, ''V. m. mutica'', due to geographical isolation, and that any other kit foxes may be included in a second subspecies, ''V. m. macrotis''.<ref name="MercureRalls1993"/><ref name="iucn status 19 November 2021" />
[[File:San Joaquin Kit fox B-40-13 08 20 1993.jpg|thumb|left|San Joaquin kit fox at the California Living Museum in Bakersfield]]
===Subspecies===
The [[endangered]] [[San Joaquin kit fox]] (''Vulpes macrotis mutica'') was formerly very common in the [[San Joaquin Valley]] and through much of [[Central California]]. Its 1990 population was estimated to be 7,000. This subspecies is still endangered, after nearly 50 years of being on the Endangered Species List. Officially, this subspecies was listed March 3, 1967.<ref>{{cite web |title=San Joaquin Kit fox (Vulpes macrotis mutica) |url=http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=A006 |publisher=U.S. Fish and Wildlife Service Home Page |archive-url=https://web.archive.org/web/20111015043132/https://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=A006#lifeHistory |archive-date=2011-10-15 |date=2011-10-14 |url-status=dead}}</ref>  On September 26, 2007, Wildlands Inc. announced the designation of the 684 acre (277 ha) Deadman Creek Conservation Bank, which is intended specifically to protect habitat of the San Joaquin kit fox.<ref name=enn>[http://www.enn.com/animals/article/23452 Kit fox Gets Some Protection, In California], Environmental News Network, September 27, 2007</ref> However, the population continues to decline mostly due to heavy habitat loss. Other factors include competition from [[red fox]]es and the extermination of the [[wolf]] from California, which has left the [[coyote]] as the dominant meso-predator in kit fox territory, bringing an imbalance in ecosystem relationships.<ref>{{Cite news|title=Urban Landscape Attributes and Intraguild Competition Affect San Joaquin Kit Fox Occupancy and Spatiotemporal Activity Nicole Anne Deatherage Department of Biology, California State University, Bakersfield|url=https://esrp.csustan.edu/publications/pdf/Deatherage%202020_Urban%20KF%20occupancy_CSUB%20thesis.pdf}}</ref><ref>{{Cite web|title=San Joaquin Kit Fox {{!}} Encyclopedia.com|url=https://www.encyclopedia.com/environment/science-magazines/san-joaquin-kit-fox|access-date=2021-04-15|website=www.encyclopedia.com}}</ref>
==Appearance==
The kit fox is one of the smallest species of the family [[Canidae]] found in North America. It has large ears, between {{convert|71|and|95|mm|in|abbr=on}}, that help the fox dissipate heat and give it exceptional hearing (much like those of the [[fennec fox]]). This species exhibits little [[sexual dimorphism]], with the male being slightly larger. The average species weight is between {{convert|1.6|and|2.7|kg|lb|abbr=on}}. The body length is {{convert|455|to|535|mm|in|abbr=on}}, with a long tail (about 40% of total length), adding another {{convert|260|–|323|mm|in|abbr=on}}.<ref name="Sillero-Zubiri2004">{{Cite book |publisher=Oxford University Press Oxford |isbn=0-19-851556-1 |last1=Sillero-Zubiri |first1=Claudi |last2=Macdonald |first2=David Whyte |title=The biology and conservation of wild canids |date=2004 |location=New York }}</ref>
The color and texture of the coat vary geographically. In general, the dorsal color is grizzled or yellowish-gray. The grizzled appearance is the result of guard hairs that are typically black-tipped or with two black bands separated by a white band. The guard hairs are less than {{convert|50|mm}} long, and particularly prominent in the middle of the back. The soles of the legs are protected by stiff tufts of hair, a trait that improves traction on loose sandy surfaces as well as protection against extreme temperatures; muzzles and vibrissae are generally black to brown. The tail is bushy and gray, with a black tip,<ref name="ADW"/> and the caudal gland has a pronounced black spot.<ref name="McGrew1979">{{cite journal |last1=McGrew |first1=John C. |title=Vulpes macrotis |journal=Mammalian Species |date=8 June 1979 |issue=123 |pages=1–6 |doi=10.2307/3504038 |jstor=3504038 |s2cid=253961802 |doi-access=free }}</ref> Unlike the [[gray fox]], it has no stripe along the length of its tail. Its color ranges from yellow to gray, and the back is usually darker than the majority of its coat; its belly and inner ears are usually lighter. It has distinct dark patches around the nose.<ref name="ADW"/> The ears are tan or gray on the back, turning to buff or orange at the base. The shoulders, the lower sides, the flanks, and the strip about 25 mm wide across the chest range in color from buffy to orange.<ref name="McGrew1979"/>
==Distribution and habitat==
The northernmost part of its range is the arid interior of Oregon. Its eastern limit is southwestern Colorado. It can be found south through Nevada, Utah, southeastern California, Arizona, New Mexico, and into western Texas.<ref name="ADW">{{cite web |last1=Patton |first1=Allen |title=Vulpes macrotis (kit fox) |url=https://animaldiversity.org/accounts/Vulpes_macrotis/ |website=Animal Diversity Web |access-date=9 November 2020 |language=en}}</ref>
Kit foxes inhabit arid and semi-arid regions encompassing [[desert scrub]], [[chaparral]], [[halophytic]] regions, and [[grassland]]s. Generally, areas with sparse ground cover are favored.<ref name="iucn status 19 November 2021" /> Vegetation habitats vary with the regional fauna, but some examples are [[sagebrush]] ''Artemisia tridentata'' and [[saltbrush]] ''Atriplex polycarpa''.<ref name="ADW"/> Loose textured soils may be prioritized for denning. Kit Foxes can also be found in agricultural areas, in particular orchards, on a small basis, and can even inhabit urban areas.<ref name="iucn status 19 November 2021" /> They are found at elevations of {{convert|400|to|1,900|m|ft|sp=us}} above sea level.<ref name="ADW"/>
==Behavior==
[[File:Kit foxes at the Nevada Test Site.jpg|thumb|Kit foxes peer from a culvert at a construction site on the [[Nevada Test Site]]]]
Kit foxes are mostly [[nocturnality|nocturnal]]<ref name="nocturnal">{{cite web|url=http://digital-desert.com/wildlife/kit-fox.html |title=Kit Fox |publisher=Digital Desert |access-date=2014-07-16}}</ref> and sometimes crepuscular;<ref name="ADW"/> they escape heat stress during the day by resting in underground dens.<ref name="Sheldon1992"/> Kit foxes normally forage on their own. Kit foxes are not exceptionally territorial, preferring to live in pairs or small groups of relatives.<ref name="ADW"/>
Dens are used during the year for daytime resting, escaping predators, avoiding extreme heat, preserving moisture, and carrying and rearing young.<ref name="Egoscue1962"/> Kit Foxes will dig their own dens, but they can also modify and use the burrows of badgers, ground squirrels, prairie dogs, and kangaroo rats.<ref name="iucn status 19 November 2021" /> Dens are spread across the home range, and an individual fox usually uses more than 11 dens in a given year.<ref name="iucn status 19 November 2021" /> They normally rest in their dens during the day, but sometimes can emerge to bask and, when pups are young, to play.<ref name="Sheldon1992"/>
In comparison to many canids that pants only at the resonant frequency of the thorax, kit foxes pants at a rate proportional to the ambient temperature before the rate exceeds the resonant frequency. In doing so, kit foxes exercise the economics of water at the cost of energy.<ref name="McGrew1979"/> The apparent velocity of kit foxes is essentially an illusion created by their limited size and [[cryptic coloration]], and their incredible ability to evade and change directions. An accurate account clocked a fox kit at around 40 km/h in front of the car, but the fox was easily exhausted.<ref name="McGrew1979"/>
==Diet==
Kit foxes are opportunistic [[omnivore]]s and [[scavenger]]s, possibly regulated by prey abundance,<ref name="Cypher2003">{{cite book |last1=Cypher |first1=B.L. |editor1-last=Feldhamer |editor1-first=G. A. |editor2-last=Thompson |editor2-first=B.C. |editor3-last=Chapman |editor3-first=J.A. |title=Wild Mammals of North America: Biology, Management, and Conservation |date=2003 |publisher=The Johns Hopkins University Press |location=Baltimore, Maryland |isbn=9780801874161 |pages=511–546 |chapter=Foxes}}</ref> but primarily [[carnivore|carnivorous]]. In the Californian deserts, its primary prey is [[Merriam's kangaroo rat]] (''Dipodomys merriami'').<ref>{{cite web |title=Desert Kit Fox |url=https://www.nps.gov/jotr/learn/nature/kitfox.htm |website=www.nps.gov |publisher=Joshua Tree National Park (U.S. National Park Service) |access-date=9 November 2020 |language=en}}</ref> Other common prey species include [[lagomorphs]], [[rodents]] and [[insects]]. Kit foxes also consume birds, reptiles, carrion, fish, and rarely, plant material, such as [[tomato]]es (''[[Lycopersicon esculentum]]''), cactus fruits (''[[Carnegiea gigantea]]'') and other fruits. Different kit fox families can occupy the same hunting grounds, but do not generally go hunting at the same time.<ref name="ADW"/> Kit foxes are also known to [[Cache (biology)|cache]] food and eat human food.<ref name="Cypher2003"/> [[Black-tailed jackrabbit]]s represent the upper size limit of prey.<ref name="Sheldon1992"/>
==Mating and reproduction==
[[File:Vulpes macrotis mutica with pups.jpg|thumb|[[San Joaquin kit fox]] family]]
{{see also|Fox#Sexual characteristics}}
The kit fox is a [[socially monogamous]] species,<ref>{{cite journal |last1=Ralls |first1=Katherine |last2=Cypher |first2=Brian |last3=Spiegel |first3=Linda K. |title=Social Monogamy in Kit Foxes: Formation, Association, Duration, and Dissolution of Mated Pairs |journal=Journal of Mammalogy |date=December 2007 |volume=88 |issue=6 |pages=1439–1446 |doi=10.1644/06-MAMM-A-348R.1 |language=en |issn=0022-2372 |doi-access=free }}</ref>  and the mated pair remains together throughout the year.<ref name="Sheldon1992"/> However, [[Animal sexual behaviour#Polygamy|polygamous]] mating relationships have been observed.<ref name="Egoscue1962">{{cite journal |last1=Egoscue |first1=Harold J. |title=Ecology and Life History of the Kit Fox in Tooele County, Utah |journal=Ecology |date=July 1962 |volume=43 |issue=3 |pages=481–497 |doi=10.2307/1933376 |jstor=1933376 |bibcode=1962Ecol...43..481E |url=https://www.jstor.org/stable/1933376}}</ref> Female foxes begin searching for natal dens in September and October and usually usable dens are visited and cleaned of debris before the final selection is made. No nest as such is built, but new entrances and tunnels can be added to the den. As with most canids, copulation ends with a "tie" during which the penis is locked in the female's vagina.<ref name="McGrew1979"/><ref name="Egoscue1956">{{cite journal |last1=Egoscue |first1=Harold J. |title=Preliminary Studies of the Kit Fox in Utah |journal=Journal of Mammalogy |date=August 1956 |volume=37 |issue=3 |pages=351–357 |doi=10.2307/1376734|jstor=1376734 }}</ref>
Females are [[monoestrous]]. Male and female kit foxes usually establish mating pairs during October and November, and they mate from December to January-February. Gestation lasts probably around 49–56 days, and the litters are born in February or March; litter size is usually four or five, and the sex ratio is roughly even. They do not emerge from the den until they are at least four weeks old, and are weaned after about eight weeks and become independent at five to six months old. They become [[sexually mature]] at 10 months. Both parents take part in raising and protecting their young. Pups emerge from the den at about one month of age and spend several hours each day playing outside the entrance. The male seems to do most of the hunting during this period, and later, both parents provide food until the pups start to forage with them at three to four months of age.<ref name="McGrew1979"/><ref name="Sheldon1992"/>
Survival and mortality rates of kit foxes can vary significantly year to year. In captivity, they have lived 10 to 12 years;<ref name="USDA">{{Cite report|last1=Meaney|first1=Carron A.|last2=Reed-Eckert|first2=Melissa|last3=Beauvais|first3=Gary P.|title=Kit Fox (''Vulpes macrotis''): A Technical Conservation Assessment|date=2006|url=https://digitallibrary.utah.gov/awweb/awarchive?item=66201|publisher=USDA Forest Service, Rocky Mountain Region|location=United States|pages=44|language=en|access-date=2020-11-09|archive-date=2020-04-25|archive-url=https://web.archive.org/web/20200425040422/https://digitallibrary.utah.gov/awweb/awarchive?item=66201|url-status=dead}}</ref> while the average lifespan of a wild kit fox is 5.5 years.<ref name="ADW"/> One Californian study of 144 kit fox pups showed a 74% mortality rate in pups within the first year.<ref name="USDA"/>
==References==
{{Reflist}}
==External links==
{{Commons|Vulpes macrotis}}
{{Wikispecies|Vulpes macrotis}}
*ARKive – [https://web.archive.org/web/20100918123510/http://www.arkive.org/kit-fox/vulpes-macrotis/ images and movies of the kit fox ''(Vulpes macrotis)'']
*NPS - [https://www.nps.gov/jotr/learn/nature/kitfox.htm information about Kit Fox in Joshua Tree National Park]
{{Carnivora|Ca.}}
{{Taxonbar|from=Q745751}}
{{Authority control}}
[[Category:Vulpes|kit fox]]
[[Category:Carnivorans of North America]]
[[Category:Mammals of Mexico]]
[[Category:Mammals of the United States]]
[[Category:Fauna of the Southwestern United States]]
[[Category:Fauna of the Western United States]]
[[Category:Fauna of the Baja California Peninsula]]
[[Category:Fauna of the Sonoran Desert]]
[[Category:Fauna of the Colorado Desert]]
[[Category:Fauna of Northern Mexico]]
[[Category:Least concern biota of the United States]]
[[Category:Least concern biota of North America]]
[[Category:Mammals described in 1888|kit fox]]
[[Category:Taxa named by Clinton Hart Merriam]]