Foxes are small-to-medium-sized animals that eat both plants and meat. They belong to several groups within the Canidae family. Foxes have a flat head, tall triangular ears, a narrow snout that points upward slightly, and a long, fluffy tail called a "brush."

Twelve species are part of the "true fox" group in the Vulpes genus. Another 25 species, which may be alive or extinct, are sometimes called foxes. These include some South American foxes and other groups like the bat-eared fox, gray fox, and island fox.

Foxes live on every continent except Antarctica. The most common and widely found species is the red fox (Vulpes vulpes), which has about 47 known subgroups. Foxes are found all over the world, and their reputation for being clever has made them important in stories and traditions in many cultures. Hunting foxes with groups of dogs, a practice long used in Europe, especially in the British Isles, was brought to other parts of the world by European settlers.

Etymology

The word "fox" comes from Old English and is related to the Proto-Germanic word fuhsaz. This word itself comes from the Proto-Indo-European word puḱ-, meaning "thick-haired, tail." Male foxes are called dogs, tods, or reynards; females are called vixens; and young foxes are called cubs, pups, or kits. However, the term "kit" should not be confused with the kit fox, which is a different species. The word "vixen" is one of the few modern English words that still use the "v" sound from the Middle English southern dialect, instead of the "f" sound used in northern England. A group of foxes may be called a skulk, leash, or earth.

Biology

Foxes are usually smaller than some other members of the Canidae family, such as wolves and jackals, but may be larger than others, like raccoon dogs. The largest species, the red fox, has males weighing between 4.1 and 8.7 kg (9.0 and 19.2 lb). The smallest species, the fennec fox, weighs 0.7 to 1.6 kg (1 1/2 to 3 1/2 lb).

Foxes typically have a triangular face, pointed ears, a long snout, and a bushy tail. They walk on their toes, a feature called digitigrade. Unlike most Canidae members, foxes have claws that can be partially retracted. Their whiskers, or vibrissae, are black. The whiskers on the muzzle, called mystacial vibrissae, are 100–110 millimetres (3 7/8–4 3/8 inches) long, while those elsewhere on the head are shorter. Whiskers on the forelimbs, called carpal vibrissae, average 40 mm (1 5/8 inches) long and point downward and backward. Other physical traits vary based on habitat and adaptation.

Foxes differ in fur color, length, and density. Coat colors range from white to black-and-white to black with white or gray on the underside. Desert-adapted species, like fennec and kit foxes, have large ears and short fur to stay cool. Arctic foxes have small ears, short limbs, and thick fur to stay warm. Red foxes usually have an auburn coat, with a white tip on the tail.

Fox fur changes with the seasons. Winter coats are thicker and darker, while summer coats are lighter. Foxes shed their winter fur once a year, starting at the feet and moving up the legs and back. Coat color may also change as foxes age.

Foxes have 42 teeth, with the formula I 3/3, C 1/1, PM 4/4, M 3/2. Bat-eared foxes have six extra molars, totaling 48 teeth. Foxes have strong carnassial teeth, which are sharp and used to tear meat. Their canines are also strong, helping them grip prey.

In the wild, foxes typically live 1 to 3 years, though some may live up to 10 years. Unlike many canids, foxes do not always live in packs. They often live in small family groups, though some, like Arctic foxes, are solitary.

Foxes are omnivores. They eat insects, small vertebrates like reptiles and birds, eggs, and plants. Most foxes eat about 1 kg (2.2 lb) of food daily. They store extra food by burying it under leaves, snow, or soil. When hunting, foxes crouch to hide and then leap to catch prey. They use their strong canines to grip and shake prey until it is dead or ready to be eaten.

The gray fox is one of only two canine species that can climb trees; the other is the raccoon dog.

Male foxes have testes that stay close to the body even after descending. Like other canines, they have a baculum, or penile bone. Red fox testes are smaller than Arctic fox testes. Sperm production in red foxes starts in August–September, with testes reaching maximum weight in December–February.

Vixens are in heat for 1 to 6 days, with a 12-month reproductive cycle. Eggs are released during estrus without needing stimulation from mating. After fertilization, gestation lasts 52 to 53 days. Foxes usually have litters of 4 to 5 kits, with an 80% pregnancy success rate. Litter sizes vary by species and environment—Arctic foxes may have up to 11 kits.

Vixens typically have six or eight mammae. Each teat has 8 to 20 lactiferous ducts, which carry milk from the mammary gland to the nipple.

Foxes have a wide range of vocalizations. In domesticated foxes, whining remains in adults as a sign of excitement or submission around their owners.

Conservation

Several types of foxes are in danger in their natural homes. Problems that harm foxes include losing their homes and being hunted for their fur, other goods, or to control their numbers. Because foxes are good at finding food in different places and are hardworking, people sometimes see them as pests. However, foxes have also been used to help control pests on fruit farms without harming the fruit.

The island fox is a species that is nearly threatened worldwide but is becoming more endangered on the California Channel Islands. Populations on islands are usually smaller than those on the mainland because of limited space, food, and shelter. This makes island animals more likely to be harmed by outside dangers like new predators, humans, or extreme weather.

On the California Channel Islands, the island fox population dropped because of a disease called canine distemper virus between 1999 and 2000 and attacks by non-native golden eagles. Since 1993, golden eagles have caused the fox population to decrease by up to 95%. With so few foxes, the population faced an Allee effect, which happens when very few animals make it harder for them to survive and reproduce. To help, conservationists took healthy foxes from the wild to breed them in captivity until there were enough to return to the wild. Non-native animals that were eating plants were also removed to let native plants grow, giving foxes better protection from eagles.

Darwin's fox was once considered critically endangered because there were only about 250 adult foxes and they lived in a very small area. However, the IUCN later changed their status to endangered in 2016 after finding that Darwin's foxes live in a larger area than previously thought. On the Chilean mainland, Darwin's foxes are found mainly in Nahuelbuta National Park and nearby rainforests. On Chiloé Island, they live in forests from the southern to the northwestern parts of the island. Although Nahuelbuta National Park is protected, most Darwin's foxes live on Chiloé Island.

A big problem for Darwin's foxes is their shrinking habitat because forests are being cut down or burned. This loss of forest allows another animal, the chilla fox, to thrive in open areas, making it harder for Darwin's foxes to survive. Another issue is that Darwin's foxes are not strong enough to fight diseases spread by pet dogs. To help Darwin's foxes, researchers suggest protecting forests that connect Nahuelbuta National Park to the coast of Chile and then to Chiloé Island. These forests form a path more than 400 kilometers long. They also recommend checking other forests in Chile to see if Darwin's foxes could live there in the future. Finally, they suggest starting a program to breed Darwin's foxes in captivity because there are so few adult foxes left in the wild.

Relationships with humans

Foxes are sometimes seen as pests because they steal food from farms, such as chickens and other small animals. Attacks on people are rare. Many foxes live near humans, with some species living entirely in cities. Urban foxes often live longer and have fewer babies than foxes in rural areas. In Europe, city foxes are common and have different behaviors compared to rural foxes, such as living in larger groups and having smaller territories. Foxes have been brought to many places around the world, sometimes harming local plants and animals.

In some countries, foxes are major predators of rabbits and chickens. Scientists studied how the numbers of these animals changed over time, which led to the development of the Lotka–Volterra equation. Fox meat can be eaten, but it is not commonly eaten in any country.

Fox hunting began in the United Kingdom in the 16th century. Hunting with dogs is now illegal in the UK, but hunting without dogs is still allowed. Red foxes were brought to Australia in the 1800s for hunting, and they have spread widely. They have harmed many native animals and often attack young sheep.

Most foxes are not fully domesticated, but some have been raised in captivity. A famous example is the Russian silver fox, which was bred over nearly 50 years in the Soviet Union and Russia. This breeding changed the foxes' appearance and behavior, making them more like pets, with features such as curly tails and floppy ears. These foxes became more friendly and would let people touch them.

Foxes are among the few mammals that can live in urban areas, such as suburbs. They eat a variety of foods, including leftovers from humans, and are often active at night, making them hard to spot. Urban foxes sometimes harm small pets like cats and dogs, leading to efforts to keep them away from cities.

The San Joaquin kit fox is an endangered species that lives in urban areas of southern California. It eats small animals like mice, rabbits, and insects, and has adapted to live in places like golf courses and school grounds.

Foxes appear in stories and myths around the world, often as clever or tricky characters. In European, Persian, East Asian, and Native American folklore, foxes are known for their ability to avoid being caught, which makes them symbols of cunning. In East Asian stories, foxes are sometimes shown as magical beings that can change shape or appear as humans. In Chinese and Japanese myths, nine-tailed foxes are often seen as either lucky or dangerous.

The constellation Vulpecula in the sky is named after a fox.