Swift Fox
From Wikipedia, the free encyclopedia
| Swift Fox[1] | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 |
||||||||||||||
| Conservation status | ||||||||||||||
| Scientific classification | ||||||||||||||
|
||||||||||||||
| Binomial name | ||||||||||||||
| Vulpes velox (Say, 1823) |
||||||||||||||
| Synonyms | ||||||||||||||
|
The Swift Fox (Vulpes velox) is a small fox found in the western grasslands of North America, such as Colorado, New Mexico and Texas.[1] It also lives in Manitoba, Saskatchewan and Alberta in Canada, where it was previously extinct.[2]
Contents |
[edit] Taxonomy
The Swift Fox is closely related genetically to the Kit Fox Vulpes macrotis, but occupies a different geographical range. The two have historically been regarded as the same species for reasons basically related to size: the Kit Fox is slightly smaller than the Swift Fox, and the former has a narrower snout. However, hybrids between the two occur naturally where their ranges overlap, and some mammalogists classify the two as subspecies of a single species, usually treated as Vulpes velox (with the Swift Fox being described as V. velox velox and the Kit Fox as V. velox macrotis).[3] The molecular genetics evidence is not conclusive however, and some of those who have used it continue to treat the Swift Fox and Kit Fox as separate species.[4]
[edit] Description
The Swift Fox has a dark, grayish, tan coloration that extends to a yellowish tan color across its sides and legs.[5] The throat, chest, and belly range from pale yellow to white in color.[5] Its tail is black-tipped, and it has black patches on its muzzle.[5] Its ears are noticeably large.[5] It is about 12 inches in height, and 31 inches long, measuring from the head to the tip of the tail, or about the size of a domestic cat.[5] Its weight ranges from around five to seven pounds.[5] Males and females are similar in appearance, although males are slightly larger.[6]
[edit] Habitat and distribution
The Swift Fox resides primariliy in deserts and short-grass prairies. They form their dens in sandy soil on open prairies, in plowed fields, or along fences.[6] It is native to the Great Plains region of North America, and its range extends north to the central part of Alberta, Canada, and south to Texas. It reaches from western Iowa to Colorado, Kansas, Wyoming, and Montana.[5]
[edit] Conservation status
The Swift Fox was once a severely endangered species, due to predator control programs in the 1930s that were aimed mostly at the Gray Wolf and the Coyote.[6] The species was extirpated from Canada by 1978,[2] but a reintroduction program started in 1983 has been successful in establishing small populations in southeast Alberta and southwest Saskatchewan, despite the fact that many reintroduced individuals do not survive their first year.[6] In May 2000, the Canadian Species at Risk Act listed the Swift Fox as an endangered species in Canada.[7]
Exact population numbers of the Swift Fox are unknown, but it is known that they currently inhabit only 40% of their historic range.[5] In addition to its populations in Canada, there are also swift fox populations in the United States, ranging from South Dakota to Texas.[6] Although the swift fox's population is only stable in the central part of its range,[6] Ithe IUCN Red List characterizes it as of Least Concern.[2]
[edit] Behavior
In the wild, the Swift Fox usually lives 3-6 years, but may live up to 14 years in captivity.[6] It is primarily nocturnal, spending only evenings and nighttime above ground in the summer.[6] Day time activities are usually confined to the den, but it has been known to spend the warm midday period above ground during the winter.[6]
The Swift Fox suffers serious predation by the Coyote, and is more heavily dependent on its den than most North American canids, using them as shelter from predators.[6] These dens are usually underground burrows that are two to four meters in length.[6] It suffers serious predation by the Coyote.
It runs very fast, at speeds of over 50 kilometers per hour.[6]
[edit] Reproduction
The adult Swift Fox's breeding season varies with region. In the southern United States, it mates between December and February with pups born in March and early April,[5][6] while in Canada, the breeding season begins in March, and pups are born in mid-May.[6] The male Swift Fox matures and may mate at one, while the female usually waits until her second year before breeding.[6] Adults live in pairs, and although some individuals mate for life, others choose different partners each year.[6] Gestation takes around 51 days, and two to six kits are born.[5][6]
The Swift Fox only has one litter annually, but may occupy up to thirteen dens in one year, moving because prey is scarce or because skin parasites build up inside the den. Sometimes it makes other burrows from other animals bigger, even though it is completely capable of digging one on its own. Pups are born in the den and typically remain there for approximately one month.[6] A newborn pup's eyes and ears remain closed for ten to fifteen days, leaving it dependent on the mother for food and protection during this time.[6] It is usually weaned around six or seven weeks old and remains with its parents until fall.[6] Recent research has shown that social organization in the Swift Fox is unusual among canids, since it is based on the females. Females maintain territories at all times, but males emigrate if the resident female is killed or removed.
[edit] Diet
Like most canids, the Swift Fox is an omnivore.[5] Rabbits, mice, ground squirrels, birds, insects and lizards are staples.[5] Grasses and fruits round out its diet. However, like any efficient forager, the Swift Fox takes advantage of seasonal foods. During the summer, adults eat large amounts of insects, including beetles and grasshoppers and feeds their young with larger prey items. Winter-killed deer and other carrion may also be important food sources.
[edit] References
- ^ a b Wozencraft, W. C. (16 November 2005). in Wilson, D. E., and Reeder, D. M. (eds): Mammal Species of the World, 3rd edition, Johns Hopkins University Press, {{{pages}}}. ISBN 0-801-88221-4.
- ^ a b c d Sillero-Zubiri & Hoffmann (2004). Vulpes velox. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 2006-05-11. Database entry includes justification for why this species is of least concern
- ^ Dragoo, J. W., Choate, J. R., Yates, T. L., & O'Farrell, T. P. (1990). "Evolutionary and taxonomic relationships among North American arid-land foxes". Journal of Mammalogy 71: 318-332.
- ^ Mercure, A., Ralls, K., Koepflik, P., & Wayne, R. K. (1993). "Genetic subdivisions among small canids - mitochondrial-DNA differentiation of swift, kit, and arctic foxes". Evolution 47: 1313-1328.
- ^ a b c d e f g h i j k l Defenders of Wildlife. Swift Fox - Defenders of Wildlife (English). Retrieved on 2008-04-21.
- ^ a b c d e f g h i j k l m n o p q r s t Resmer, Karen. Vulpes velox (English). Retrieved on 2008-04-17.
- ^ Species at risk - Swift Fox. Environment Canada (2006-05-08).
[edit] General References
- Egoscue, H. J. (1979). "Vulpes velox". Mammalian Species 122: 1-5.
- Kamler, J. F., Ballard, W. B., Gese, E. M., Harrison, R. L., Karki, S., & Mote (2004). "Adult male emigration and a female-based social organization in swift foxes, Vulpes velox". Animal Behaviour 67: 699-702.
|
||||||||||||||||||||||
