Red fox

Name and taxonomy

The word fox comes from Old English and, further back, from an ancient root that meant thick-haired or tail. The Welsh name llwynog means bushy, and the Portuguese raposa comes from rabo, a tail. A male is a dog or tod, a female a vixen, and the young are kits or cubs. A family group is called a skulk or a leash.

Carl Linnaeus described the red fox in 1758, and the type locality was later fixed at Uppsala in Sweden. Mammal Species of the World lists 45 subspecies, and a 46th, the Sacramento Valley red fox, was added in 2010. They fall into two kinds: large, bright northern foxes and small grey foxes of the Asian and North African deserts. Its nearest relative is Rüppell's fox of the Sahara, which sits inside the red fox line in mitochondrial DNA.

Evolution and relatives

The red fox arose in Eurasia, from either Vulpes alopecoides or the Chinese V. chikushanensis. The oldest fossils come from Baranya County in Hungary and date from 3.4 to 1.8 million years ago. The modern species is at least 400,000 years old, and its earliest bones turn up in the rubbish heaps of early human camps. People probably hunted it for meat and fur, and the fox probably scavenged their leftovers in return.

Red foxes reached North America in two waves, the second about 130,000 years ago. American foxes have been cut off from Old World foxes for over 400,000 years. Two refuges survived the last ice age there: one in Alaska and western Canada, and a mountain one from the Rockies to the Sierra Nevada.

Appearance

The red fox stands 35 to 50 centimetres at the shoulder and measures 45 to 90 cm in head and body. The tail adds 30 to 55.5 cm, about 70 percent of the body length, and brushes the ground when the fox stands. Adults weigh 3 to 14 kilograms, and vixens weigh 15% to 20% less than dogs. The largest fox on record in Britain was 1.4 metres long and 17.2 kg, killed in Aberdeenshire in 2012. Northern foxes are big and bright, while desert foxes are small with longer legs and bigger ears.

The typical coat is bright rusty red with yellow tints, darker along the spine and mottled silver on the lower back. The chin, throat and chest are white, the paws black, and the backs of the ears black. The tail is red above, pale below and tipped with white, with a black spot at its base over a scent gland. The eyes are yellow in adults, with oval pupils that stand upright like a cat's. The winter coat is long, dense and silky, and the American foxes have the finest fur.

Three colour forms occur in the wild: red, cross and silver. A cross fox carries one black stripe along the spine and a second over the shoulders, and makes up about 25% of foxes. A silver fox is nearly black with silver tips and makes up about 10%, and furriers prize it most.

Habitat and range

The species occupies close to 70,000,000 square kilometres, a larger area than any other wild carnivore holds. It lives across Europe, Asia outside the far southeast, North Africa north of the Sahara, and North America outside the southwest and Mexico. It does not live on the Arctic islands, in the far north of Siberia or in the harshest deserts. GBIF holds records from 101 countries and more than two million occurrences, though that count includes escapes and introductions.

The fox likes a mix of habitats: edges, scrub and woodland beside open fields. It also lives on tundra, moorland, mountains, dunes, deserts and farmland. Since the 1930s it has moved into cities, first in Britain, then across Europe, Japan, North America and Australia. Urban foxes do best in low-density suburbs with gardens, where a home range covers only 25 to 40 hectares. Britain's urban foxes rose from about 33,000 in 1995 to 150,000 in 2017.

British settlers released foxes in Australia in the 1830s and 1840s so they could hunt them. By 2012 there were more than 7.2 million across the mainland. They never took hold in Tasmania, probably because the Tasmanian devil outcompeted them.

Diet and hunting

The red fox is an omnivore with one of the widest diets of any mammal. It takes more than 300 kinds of animal: voles, mice, gerbils, squirrels, rabbits, hares, game birds, songbirds, reptiles, beetles and worms. Its usual prey weighs up to 3.5 kilograms, and it needs about 500 grams of food a day. In autumn fruit can make up the whole diet: blackberries, cherries, apples, plums, grapes and acorns. Human food makes up 35% of an urban fox's diet against 6% for a country fox.

The fox hunts alone, mostly in the hours before sunrise and after sunset. It finds a mouse by sound, freezes, then leaps high and comes down on the spot with its front paws. It can land on a target up to 5 metres away and steers in mid-air with its tail. It can hear a mouse squeak at 100 metres and pinpoint the sound to within one degree. Foxes hunting under snow or long grass seem to line up with the Earth's magnetic field, which may improve their aim.

A fox buries surplus food and remembers where, and it marks empty caches with urine so it does not dig them up again. It sometimes kills far more than it can eat. In one breeding season four foxes killed around 200 black-headed gulls each on dark, windy nights.

Behaviour and social life

Red foxes do not form packs, but they are not solitary either. The basic unit is a mated pair. A group of up to six may share a territory: one dog and two to five vixens, usually related. Where food is rich and hunting light, one to eight subordinates may stay, mostly last year's young. These helpers guard, groom, feed and play with the breeding vixen's kits. A young fox leaves when it has a good chance of winning ground of its own, and otherwise waits a year.

Home ranges run from 5 to 12 square kilometres in good country and 20 to 50 in poor country. Both sexes mark with urine, the dog with a raised leg and the vixen squatting, using up to 12 postures. Young foxes disperse in their first autumn, some only 10 kilometres and some almost 400. A fox can jump a 2 metre fence, swims well and trots at 6 to 13 kilometres per hour.

Outside the breeding season most foxes sleep in the open in thick cover and use a burrow only in bad weather. The earth is dug in well-drained soil on a slope or riverbank, often taken over from a rabbit, badger or marmot. A main passage can run 17 metres, though 5 to 7 is usual, and the den lies 0.5 to 2.5 metres down.

Communication and senses

Foxes have a wide vocal range across five octaves, with 12 adult calls and 8 kit calls identified. The commonest is a bark of three to five syllables, written as wow wow wow, given by two foxes approaching each other. A long drawn-out scream in winter is thought to be a vixen calling for a mate. Rivals make a rattling throaty sound called gekkering, and a submissive fox gives a siren-like shriek. Each fox has its own voice, and captive foxes answer recordings of their pen-mates but not of strangers.

Body language uses the ears, the tail and the whole posture, and the coat markings make the signals plain. A frightened fox grins, arches its back, crouches and lashes its tail with its ears flat. Scent comes from urine, droppings, anal sacs, a tail gland that smells of violets, and glands on the feet and lips. Sight reacts mainly to movement, hearing is acute, and smell is good but weaker than a scent hound's.

Reproduction and life cycle

Red foxes breed once a year, in winter: December to January in the south and February to April in the far north. The vixen is in heat for 1 to 6 days, and dogs fight over her. Mating ties the pair together for 15 to 20 minutes or more, often in a burrow. Most pairs are monogamous, but a dog may hold two vixens, and DNA from one population showed mixed litters and incest. Gestation lasts about 52 days, within a range of 49 to 58.

A litter holds four to six kits as a rule, and up to 13 where foxes die young. Kits arrive blind, deaf and toothless, covered in dark brown fluff, and weigh 56 to 110 grams. The vixen stays with them for 2 to 3 weeks because they cannot keep warm alone, and the dog brings her food. Their eyes open at 13 to 15 days, blue at first and amber by 4 to 5 weeks.

Kits leave the den and try solid food at 3 to 4 weeks, and suckling ends at 6 to 7 weeks. By 3 to 4 months they are long-legged and lean, and by 6 to 7 months they have adult proportions. Some vixens breed at 9 to 10 months and have their first litter at one year. A wild fox rarely lives past 5 years, and many die in their first year, while the captive record is 21.3.

Predators and threats

Golden eagles regularly take young foxes and sometimes adults, and eagle-owls and snowy owls take kits. Wolves kill and eat foxes in disputes over carcasses, and coyotes drive them off their ground. Eurasian lynx chase foxes into deep snow and kill them, and cougars, bobcats, leopards and caracals do the same elsewhere. Striped hyenas kill foxes that tease them, and wolverines take foxes asleep near carrion. Most foxes taken by predators are kits, which the family keeps close to the den.

The red fox is the main carrier of rabies in Europe. The mange mite is its worst parasite: a fox loses its fur and half its weight and dies within about four months. Foxes carry tapeworms including Echinococcus, roundworms, lungworms and up to 20 kinds of helminth in the wild.

People kill more foxes than anything else does. Germany alone killed about 600,000 in a year around 2000, Sweden and Austria 58,000 each, and Britain 21,500 to 25,000. None of this threatens the species, which grows back as fast as it is cut.

Population and conservation

The IUCN Red List rates the red fox Least Concern, and its numbers are stable or rising almost everywhere. Density varies hugely: about 3 foxes per square kilometre in the Swiss mountains and up to 30 in some British cities. Most countries treat it as a pest with no protection, though hunting seasons and trapping methods are regulated. Three Indian subspecies sit on CITES Appendix III, which controls their trade.

iNaturalist holds 156,052 observations of the species, more than for almost any other mammal. In Australia the problem runs the other way: the fox is listed among the world's 100 worst invasive species. It has driven declines in bettongs, bilbies, numbats, quokkas and other small ground mammals, many of which now survive only on fox-free islands. States pay bounties and run baiting programmes, but the fox's burrows and night habits make it hard to remove. When foxes reached Tasmania in 1999 or 2000, the state launched an eradication programme at once.

Relationship with humans

People have hunted foxes since at least the 4th century BC, when Alexander the Great rode after them. A Persian seal of 350 BC shows a horseman spearing a fox, and the Romans hunted them by AD 80. In England, Edward I kept a royal pack of foxhounds by the late 1200s, and by the Renaissance the nobility hunted foxes for sport. Virginia planters imported English foxes in 1730 because they gave a longer chase than the native grey fox.

Few animals matter more to the fur trade than the red fox. In 1985 to 1986 the trade handled 1,543,995 wild fox pelts, and foxes made up 45% of American wild-caught fur. More foxes are raised on fur farms than any other wild fur-bearer. Foxes take lambs now and then, mostly weak ones or twins, and they kill rabbits and guinea pigs left in open runs.

Urban foxes raid bins, dig up gardens and steal chickens, and complaints peak in the spring breeding season. Killing them achieves little, because new foxes fill the empty territory within months. A wild fox makes a poor pet: it grows fearful of strangers at 10 weeks, chews cables and never loses the urge to kill birds. In Russia, Dmitry Belyayev bred silver foxes for tameness over 40 years. After about 10 generations they wagged their tails and licked their keepers, and some grew floppy ears and piebald coats like dogs.

In culture and myth

Almost every culture that knows the fox calls it cunning. In Greek myth the Teumessian fox was a giant beast fated never to be caught. In Celtic tradition the fox is a symbolic animal, and in the Cotswolds witches were said to turn into foxes to steal butter. Reynard the Fox, the trickster of medieval Europe, first appeared in the poem Ysengrimus in 1150 and in the Roman de Renart in 1175.

Japanese folklore has the kitsune, a fox spirit whose powers grow with age and which can take human form. Some kitsune trick people, while others are loyal guardians, friends and wives. China has the huli jing, which may grow up to nine tails, and Korea the kumiho. Arab folklore makes the fox a coward that plays dead to lure prey close.

In Native American stories Fox is Coyote's companion and a thief who steals his food. The Achomawi say Fox and Coyote made the world together and left just before people arrived. In a Yurok tale Fox caught the Sun in a rage and tied it to a hill, where it burned a hole in the ground. An Inuit story tells of a fox who became a beautiful woman, married a hunter and left when he offended her. Modern spirit-animal writing makes the fox stand for adaptability and cleverness, which seems to be a recent gloss on the old tales.