Vulpes

Extant species

Within Vulpes, 12 separate and distinct extant species and four fossil species are described:

The Arctic fox is sometimes included in this genus as Vulpes lagopus based on the definitive mammal taxonomy list, as well as genetic evidence.

Foxes of this group (including the fennec and Arctic foxes) possess eyes with pupils that retract into vertical slits in bright light.

The red fox, Ruppell's fox, and Tibetan sand fox possess white-tipped tails. The Arctic fox's tail-tip is of the same color as the rest of the tail (white or blue-gray) Blanford's fox usually possesses a black-tipped tail, but a small number of specimens (2% in Israel, 24% in the United Arab Emirates) possess a light-tipped tail. The other foxes in this group (Bengal, Cape, corsac, fennec, kit, pale, and swift) all possess black-tipped or dark-tipped tails.

Fossil species

Early history

The oldest known fossil species within Vulpes is V. riffautae, dating back to the late Miocene of Chad, which is within the Neogene. The deposits where these fossils are found are about 7 million years old, which might make them the earliest Canidae in the Old World. They are estimated to have weighed between 1.5 and 3.5 lb. V. skinneri, from the Malapa fossil site from South Africa, is younger than V. riffautae by roughly 5 million years, and shows up in the early Pleistocene.

Two other extinct, less documented fossils are known: V. praeglacialis and V. hassani. V. praeglacialis was discovered in the Petralona Cave in Chalkidiki, Greece. The age of the deposits (Early Pleistocene) makes it the earliest occurrence of Vulpes in Europe. V. hassani is found in a Miocene-Pliocene deposit in northwestern Africa.

In the Pleistocene, Vulpes had a fairly wide distribution, with eight species found in North America. Of these eight, six are not fossil, and three species still remain in North America (V. velox, V. macrotis, and V. chama). The remaining three moved on to sections of Africa over time. V. stenognathus is extinct, but has extant sister taxa including V. chama, V. rueppellii, V. velox, and V. vulpes, which fits with these species all evolving together in North America.

V. bengalensis

Bengal foxes are endemic to India and live throughout the subcontinent, and have not been placed on the endangered species list, but have become threatened by lack of native habitat due to human expansion.

V. cana

Blanford's fox dwells in section of the Middle East including Afghanistan, Egypt, Turkestan, Iran, Pakistan, and Israel. This species prefers semiarid environments.

V. chama

The Cape fox is only found in the south of Africa, including Zimbabwe, Botswana, and South Africa. They thrive in semiarid and arid environments with rich grasslands.

V. corsac

Corsac foxes live in central Asia. Like V. chama and V. cana, they do best in semiarid deserts. This fox is within the holarctic clade of foxes. This clade also contains the Arctic fox, swift fox, and red fox. Their possible ancestor is V. praecorsac, meaning they may have had a much wider distribution in the past (Europe and Crimea).

V. ferrilata

The Tibetan sand fox, as the name suggests, is endemic to the Tibetan and Ladakh plateau in Nepal, China, Sikkim, and Bhutan. This species lives at altitudes up to 5300 m and semideserts.

V. lagopus

Arctic foxes inhabit all of the Arctic (Greenland, Russia, Canada, Alaska, Svalbard), Iceland, and parts of Scandinavia, and hold the title of being the only native land mammal in all of Iceland. This fox arrived in Iceland during the climax of the last ice age, when the seas were frozen solid enough to walk across. Two extant subpopulations of this species are alive today. The Arctic fox is most closely related to kit (V. macrotis) and corsac foxes (V. corsac).

V. macrotis

Kit foxes are an arid area-dwelling North American species. They are found in Oregon, Colorado, Nevada, Utah, California, New Mexico, and Texas. They also have a small population in Mexico.

V. pallida

The pale fox lives in upper middle Africa and is an arid area-dwelling species.

V. rueppellii

Ruppel's foxes are specific to northern Africa and sections of the Middle East.

V. velox

The swift fox is found in the western grasslands of North America, specifically Montana, Colorado, New Mexico, Oklahoma, and Texas, as well as some sections of Canada. This species is most closely related to the kit fox, but lives in a different section of North America. The two can interbreed.

V. vulpes

The red fox is the most abundant and most widely distributed species of Vulpes. They currently live in most sections of the Northern Hemisphere. They also are present in Australia, though were brought there by humans for fox hunting in the 1830s and are considered an invasive species. This species’ ancestor (either V. alopecoides or the related Chinese V. chikushanensi) originated in the Early Pleistocene and are most closely related to Ruppell’s fox (V. rueppellii).

V. zerda

The fennec fox lives in the northernmost sections of Africa. It was not previously within Vulpes, but genetic evidence shows its close relation with Blanford's fox, making it a true fox.

Anatomy

Vulpes has a very similar bone structure to its canid relatives, but does have some modifications. Although canid limbs are designed specifically for running quickly on land to catch prey, Vulpes species avoid rapid sprints, excluding being chased, and have become more specialized for leaping and grasping prey.

The adaptions for leaping, grasping, and climbing include the lengthening of hind limbs in relation to fore limbs, as well as overall slenderizing of both hind and fore limbs. Muscles are also emphasized along the axis of limbs.

Diet

This genus is omnivorous and prone to scavenging. The foods of choice for Vulpes consist of invertebrates, a variety of small vertebrates, grasses, and some angiosperms. The typical intake per day is about 1 kg. True foxes exhibit hoarding behavior or caching where they store away food for another day out of sight from other animals.

Habitat

These foxes can dwell in a number of habitats, including alpine, forest, desert, coastal, farm, and urban areas, but thrive in environments rich in food and shelter. They can be found in great numbers in suburban/residential regions. For the most part, this coexistence is agreeable for both fox and man, but can sometimes result in house pet (cat) disappearances.

Predators

Predators are dependent on location, but commonly include humans, bears, and large birds of prey, such as eagles.

General overview

Though this varies in intensity from species to species, foxes operate within a hierarchical society, where dominance is established early in life. Dominant kits receive more food and are subsequently larger. If a dispute in the hierarchy occurs, dominance is determined by fighting. The loser may be subjected to rejection from its social group, as well as serious injuries. These social groups usually consist of three or four adults and have not been documented to surpass 10 adults. Vulpes species are usually nocturnal, but do occasionally hunt and scavenge in daylight during winter.

Reproduction

A male is referred to as a dog, and the female as a vixen. They are very similar in appearance, though dogs have larger heads. Mating occurs in late winter. This mating process starts when the vixen digs out an undisclosed number of potential breeding dens and begins to release a mating scent. Gestation takes 7–8 weeks, putting typical birth occurrence in March, and on average, kits begin to emerge in late April. The parents work as a unit in the upbringing of their offspring, but do not mate for life.

After birth

Born deaf and blind, kits or cubs require their mother’s milk and complete supervision for the first four to five weeks out of the womb, but begin to be progressively weaned after the first month. Once fully weaned, kits seek out various insects. The parents supplement this diet with a variety of mammals and birds. During early to middle July, the kits are able to hunt on their own and soon move away from their parents.

Domestication

Though rare, domestication has been documented. The most notable case documented is the domestication of the silver fox in Novosibirsk, Russia, at the Siberian Institute of Cytology and Genetics. In this study, generations of silver foxes were divided into those with friendly traits and those with unfriendly traits. After 50 years, the friendly foxes developed “dog-like” domesticated traits such as spots, tail wagging, enjoyment of human touch, and barking.

Fox hunting

Fox hunting was started in the United Kingdom in the 16th century that involves tracking, chasing, and killing a fox with the aid of foxhounds and horses. It has since then spread to Europe, the United States, and Australia.