Gray fox - WikiHQ

The gray fox (Urocyon cinereoargenteus), or grey fox, is an omnivorous mammal of the family Canidae, widespread throughout North America and Central America. This species and its only congener, the diminutive island fox (Urocyon littoralis) of the California Channel Islands, are the only living members of the genus Urocyon, which is considered to be genetically sister to all other living canids. Its species name cinereoargenteus means "ashen silver".

It was once the most common fox in the eastern United States, and though still found there, human advancement and deforestation allowed the red fox to become the predominant fox-like canid. Despite this post-colonial competition, the gray fox has been able to thrive in urban and suburban environments, one of the best examples being southern Florida. The Pacific States and Great Lakes region still have the gray fox as their prevalent fox.

Etymology

The genus Urocyon comes from Ancient Greek οὐρά (ourá, "tail") + κύων (kúōn, "dog"). The species epithet cinereoargenteus is a combination of 'cinereo' (from 'cinereus') meaning ashen, and 'argenteus' (from argentum), meaning 'silver', referencing the color of the tail.

Description

The gray fox is mainly distinguished from most other canids by its grizzled upper parts, black stripe down its tail and strong neck, ending in a black-tipped tail, while the skull can be easily distinguished from all other North American canids by its widely separated temporal ridges that form a 'U'-shape. Like other canids, the fox's ears and muzzle are angular and pointed. Its claws tend to be lengthier and curved.

There is little sexual dimorphism, save for the females being slightly smaller than males. The gray fox ranges from in total length. The tail measures of that length and its hind feet measure . The gray fox typically weighs , though exceptionally large individuals can weigh as much as . The gray fox is readily distinguished from the red fox by its obvious lack of the "black stockings" that stand out on the red fox. The grey fox has a stripe of black hair that runs along the middle of its tail, and individual guard hairs that are banded with white, gray, and black.

thumb|right|Showing black tail stripe, [[Sierra Nevada]]

In contrast to the species in genus Vulpes, such as the red fox, the gray fox has oval (instead of slit-like) pupils. Its weight can be similar to that of a red fox, but the gray fox appears smaller because its fur is not as long and it has shorter limbs.

The dental formula of U. cinereoargenteus is = 42. Genetic analysis has shown that the gray fox migrated into the northeastern United States post-Pleistocene in association with the Medieval Climate Anomaly warming trend. to the northern part of South America (Venezuela and Colombia), excluding the mountains of northwestern United States. It is the only canid whose natural range spans both North and South America. In some areas, high population densities exist near brush-covered bluffs. In southeastern Mexico, the species prefers areas with a human presence such as near roads.

Behavior

The gray fox is specifically adapted to climb trees. Its strong, hooked claws allow it to scramble up trees to escape many predators, such as the domestic dog or the coyote, It descends primarily by jumping from branch to branch, or by descending slowly backwards like a domestic cat. The gray fox is primarily nocturnal or crepuscular and makes its den in hollow trees, stumps or appropriated burrows during the day. Such gray fox tree dens may be located above the ground.

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In areas where both red and gray foxes exist, the gray fox is dominant. Gray foxes may also avoid competitors by occupying different habitats from them. In California, gray foxes do this by living in chaparral where their competitors are fewer and the low shrubbery provides them a greater chance to escape from a dangerous encounter. This explains the gray fox's tendency to change behavior in response to the coyote threat, as they are essentially lower on the food chain.

Reproduction

The gray fox is assumed to be monogamous, like other foxes. The breeding season of the gray fox varies geographically; in Michigan, the gray fox mates in early March, in Alabama, breeding peaks occur in February. The gestation period lasts approximately 53 days. Litter size ranges from 1–7, with a mean of 3.8 young per female.

thumb|Kits at [[Zion Canyon]]

The sexual maturity of females is around 10 months of age. Kits begin to hunt with their parents at the age of 3 months. By the time that they are 4 months old, the kits will have developed their permanent dentition and can now easily forage on their own. The family group remains together until the autumn, when the young males reach sexual maturity, then they disperse. Adult gray foxes showed no signs of dispersion for either sex. The gray fox will typically live between six and ten years.

The annual reproductive cycle of males has been described through epididymal smears. They become fertile earlier and remain fertile longer than females. followed by lagomorphs, e.g. jackrabbit, brush rabbit, etc.

Ecosystem role

Since woodrats, cotton rats, and mice make up a large part of the gray fox's diet, they serve as important regulators of small rodent populations.

In addition to their beneficial predation on rodents, gray foxes are also less welcome hosts to some external and internal parasites, which include fleas, lice, nematodes, and tapeworms.

Hunting

Gray foxes are hunted in the U.S. The intensity of the hunting has correlated with the value of their pelts. Between the 1970–1971 and 1975–1976 hunting seasons, the price of gray fox pelts greatly increased and the number of individuals hunted jumped over six-fold from 26,109 to 163,458.

Subspecies

thumb|U. c. fraterculus<br />Tikal, Guatemala

There are 16 subspecies recognized for the gray fox. Other common parasites that were collected on gray foxes in Texas were a variety of tapeworms (Mesocestoides litteratus, Taenia pisiformis, Taenia serialis) and roundworms (Ancylostoma caninum, Ancylostoma braziliense, Haemonchus similis, Spirocerca lupi, Physaloptera rara, Eucoleus aerophilus). T. pisiformis was the most common parasite species and was associated with frequent impacts on health.

References

External links