<P> Red foxes either establish stable home ranges within particular areas or are itinerant with no fixed abode . They use their urine to mark their territories . A male fox raises one hind leg and his urine is sprayed forward in front of him, whereas a female fox squats down so that the urine is sprayed in the ground between the hind legs . Urine is also used to mark empty cache sites, used to store found food, as reminders not to waste time investigating them . The use of up to 12 different urination postures allows them to precisely control the position of the scent mark . Red foxes live in family groups sharing a joint territory . In favourable habitats and / or areas with low hunting pressure, subordinate foxes may be present in a range . Subordinate foxes may number one or two, sometimes up to eight in one territory . These subordinates could be formerly dominant animals, but are mostly young from the previous year, who act as helpers in rearing the breeding vixen's kits . Alternatively, their presence has been explained as being in response to temporary surpluses of food unrelated to assisting reproductive success . Non-breeding vixens will guard, play, groom, provision and retrieve kits, an example of kin selection . Red foxes may leave their families once they reach adulthood if the chances of winning a territory of their own are high . If not, they will stay with their parents, at the cost of postponing their own reproduction . </P> <P> Red foxes reproduce once a year in spring . Two months prior to oestrus (typically December), the reproductive organs of vixens change shape and size . By the time they enter their oestrus period, their uterine horns double in size, and their ovaries grow 1.5--2 times larger . Sperm formation in males begins in August--September, with the testicles attaining their greatest weight in December--February . The vixen's oestrus period lasts three weeks, during which the dog - foxes mate with the vixens for several days, often in burrows . The male's bulbus glandis enlarges during copulation, forming a copulatory tie which may last for more than an hour . The gestation period lasts 49--58 days . Though foxes are largely monogamous, DNA evidence from one population indicated large levels of polygyny, incest and mixed paternity litters . Subordinate vixens may become pregnant, but usually fail to whelp, or have their kits killed postpartum by either the dominant female or other subordinates . </P> <P> The average litter size consists of four to six kits, though litters of up to 13 kits have occurred . Large litters are typical in areas where fox mortality is high . Kits are born blind, deaf and toothless, with dark brown fluffy fur . At birth, they weigh 56--110 g (2.0--3.9 oz) and measure 14.5 cm (5.7 in) in body length and 7.5 cm (3.0 in) in tail length . At birth, they are short - legged, large - headed and have broad chests . Mothers remain with the kits for 2--3 weeks, as they are unable to thermoregulate . During this period, the fathers or barren vixens feed the mothers . Vixens are very protective of their kits, and have been known to even fight off terriers in their defence . If the mother dies before the kits are independent, the father takes over as their provider . The kits' eyes open after 13--15 days, during which time their ear canals open and their upper teeth erupt, with the lower teeth emerging 3--4 days later . Their eyes are initially blue, but change to amber at 4--5 weeks . Coat colour begins to change at three weeks of age, when the black eye streak appears . By one month, red and white patches are apparent on their faces . During this time, their ears erect and their muzzles elongate . Kits begin to leave their dens and experiment with solid food brought by their parents at the age of 3--4 weeks . The lactation period lasts 6--7 weeks . Their woolly coats begin to be coated by shiny guard hairs after 8 weeks . By the age of 3--4 months, the kits are long - legged, narrow - chested and sinewy . They reach adult proportions at the age of 6--7 months . Some vixens may reach sexual maturity at the age of 9--10 months, thus bearing their first litters at one year of age . In captivity, their longevity can be as long as 15 years, though in the wild they typically do not survive past 5 years of age . </P> <P> Outside the breeding season, most red foxes favour living in the open, in densely vegetated areas, though they may enter burrows to escape bad weather . Their burrows are often dug on hill or mountain slopes, ravines, bluffs, steep banks of water bodies, ditches, depressions, gutters, in rock clefts and neglected human environments . Red foxes prefer to dig their burrows on well drained soils . Dens built among tree roots can last for decades, while those dug on the steppes last only several years . They may permanently abandon their dens during mange outbreaks, possibly as a defence mechanism against the spread of disease . In the Eurasian desert regions, foxes may use the burrows of wolves, porcupines and other large mammals, as well as those dug by gerbil colonies . Compared to burrows constructed by Arctic foxes, badgers, marmots and corsac foxes, red fox dens are not overly complex . Red fox burrows are divided into a den and temporary burrows, which consist only of a small passage or cave for concealment . The main entrance of the burrow leads downwards (40--45 °) and broadens into a den, from which numerous side tunnels branch . Burrow depth ranges from 0.5--2.5 metres (1 ft 8 in--8 ft 2 in), rarely extending to ground water . The main passage can reach 17 m (56 ft) in length, standing an average of 5--7 m (16--23 ft). In spring, red foxes clear their dens of excess soil through rapid movements, first with the forepaws then with kicking motions with their hind legs, throwing the discarded soil over 2 m (6 ft 7 in) from the burrow . When kits are born, the discarded debris is trampled, thus forming a spot where the kits can play and receive food . They may share their dens with woodchucks or badgers . Unlike badgers, which fastidiously clean their earths and defecate in latrines, red foxes habitually leave pieces of prey around their dens.> The average sleep time of a captive red fox is 9.8 hours per day . </P>

How long does a red fox live in the wild