The Dog Family: Red and Corsac Foxes

Broadly speaking, many members of the dog family can be described as foxes. However, the word “fox” does not have a precise scientific definition. It is used for animals belonging to two separate evolutionary branches that are not actually close relatives. To make matters even more complicated, some species within those branches do not really fit what we would normally imagine when we hear the word “fox.”

Even so, “fox” remains a widely used term for small to medium-sized canids that commonly have bushy tails, noticeable ears, pointed faces, relatively long legs, and similar features. When people in the Northern Hemisphere hear the word “fox” without any additional description, the animal they most commonly picture is the red fox, Vulpes vulpes.

The Red Fox and Its Remarkable Range

The red fox is the largest member of the so-called true foxes. The other evolutionary branch is younger and contains animals that are actually more closely related to wolves. Red foxes are also among the most vividly coloured foxes, although their coats can vary considerably. Individuals may be brown, yellowish, or even silvery-gray.

These colour variations do not correspond neatly with the more than forty subspecies that have been described over the years. In fact, many of those classifications may represent distinctions that are finer than necessary.

Red foxes occur across almost the entirety of Europe, with Iceland and several smaller islands being notable exceptions. Although the species was first named in Europe, its range extends across most of Asia, including Japan. They are also found along the Nile Valley in Africa and in portions of the southern Mediterranean coast.

The foxes of North America were once considered a separate species, but they are now generally recognized as another form of the red fox. As a result, red foxes occur throughout Canada and across nearly all of the United States except the driest regions.

Their enormous geographical range makes red foxes one of the most widely distributed carnivorous mammals on Earth. In modern times, their distribution even exceeds that of wolves.

Introduced Red Fox Populations

The history of red foxes in North America is somewhat complicated. Many red foxes living in the eastern United States are descendants of European animals that were brought over during the colonial period.

Native populations also exist, including the animals commonly called silver foxes. This is a colour form of the red fox that was itself involved in introductions elsewhere. Silver foxes were transported from North America to Russia to support the fur industry and were later distributed to fur farms in other regions.

Red foxes were also introduced to Australia. The main reason appears to have been to provide quarry for British settlers who wanted to hunt them, rather than to use the foxes to control rabbits. As it turned out, their ability to control Australia's rabbit population was extremely limited.

Adaptable Habitat and Urban Life

Red foxes generally prefer forest edges and open woodland, but their extraordinary geographical distribution demonstrates just how adaptable they are. They can occupy habitats ranging from deserts and tundra to lowland plains and high mountain environments.

Their flexible diet also contributes greatly to their success. Like many fox species, red foxes will consume almost anything small enough for them to catch or eat, allowing them to survive in a remarkable variety of environments.

In many regions, red foxes are the largest wild mammals regularly found in urban areas. Their presence in cities became increasingly noticeable during the twentieth century, particularly as leafy residential neighborhoods expanded and created suitable habitat.

How Urban Foxes Behave

Based on available historical records, urban foxes appear to have been largely absent before approximately the 1930s. Even today, they are more commonly associated with greener suburban neighborhoods than with heavily built-up city centers or industrial districts.

This pattern appears to be particularly noticeable in North America. One possible explanation is that the continent contains more extensive wilderness areas than Europe, giving foxes less reason to enter urban environments and expose themselves to human activity.

Red foxes are naturally more active during the night than during the day, but city-dwelling individuals tend to be even more strongly nocturnal than their rural relatives. Avoiding people may therefore be an important part of their urban lifestyle.

What Urban Red Foxes Eat

City foxes frequently scavenge, including searching through household waste and other human refuse. However, garbage does not necessarily make up the majority of their diet.

A study conducted in Oxford during the 1980s found that domestic refuse accounted for only a little more than one-third of the food consumed by urban red foxes. Earthworms represented a substantial part of the remainder. Small mammals and birds together made up only about one-quarter of the diet, while fruit accounted for much of the remaining food.

This flexible feeding strategy is one of the reasons red foxes can survive successfully in environments heavily influenced by humans.

How Foxes Differ From Wolves

Foxes differ from wolves in more ways than simply body size. Although foxes are relatively social when compared with many other carnivorous mammals, they are not pack hunters.

Even in situations where several adult foxes live together, individual animals generally hunt independently. Because they hunt alone, foxes usually target prey that are smaller than themselves. Wolves, by contrast, can cooperate to bring down animals considerably larger than an individual wolf.

Red foxes, for example, generally do not consume prey weighing more than about 3.5 kilograms, or roughly 7 pounds 12 ounces, unless they encounter an animal that is already dead.

True foxes also share a characteristic hunting technique when pursuing smaller prey. They may leap vertically into the air before coming down onto their target, using their front paws to pin it to the ground.

How Foxes Teach Their Young to Hunt

Another important difference involves how adults provide food for their offspring. Wolves and related canids often return to the den and regurgitate food for their pups. Foxes instead tend to bring live prey back to the den.

This gives young foxes an opportunity to interact with the prey before eating it. By playing with live animals, the pups can begin practicing the movements and skills they will eventually need for hunting. This behavior appears to be characteristic of foxes in general rather than being unique to red foxes.

Red Fox Family Life

Red foxes commonly live in mated pairs, another pattern frequently associated with foxes. However, this arrangement is not universal, and some males may have more than one mate.

In some groups, younger females may remain with the family without producing their own offspring. Instead, they help raise the young belonging to older females. Their assistance can be surprisingly extensive, with some subordinate females even producing milk and helping nurse the pups.

Although groups generally contain no more than one adult male, the relationships between the male and his female partners are not necessarily exclusive. As a result, the exact father of individual pups may not always be certain.

Communication and Territorial Behavior

Despite being solitary hunters rather than coordinated pack animals, red foxes possess sophisticated communication systems. Researchers have documented nearly thirty different types of calls, although the exact meaning of every vocalization is not yet fully understood.

Red foxes also establish and defend territories, using scent-marking behaviors similar to those found in other members of the dog family.

In many regions, a fox pair or family group may maintain essentially the same territory throughout their lives. Urban foxes appear to behave differently, however. Individuals living in densely populated areas may change territories relatively frequently, sometimes moving to an entirely different area approximately once every 13 months.

The Corsac Fox

In many regions, including much of Europe and large parts of Canada and northern Asia, the red fox is the only native fox species. Elsewhere, it shares its territory with other foxes that may be somewhat more specialized in their habitat preferences.

One of the most widespread species living alongside the red fox is the corsac fox, Vulpes corsac, which is also a particularly close relative of the red fox.

The word “corsac” may sound like an unusual English adjective, but it is actually the Russian name for this animal. Because of this, the word “fox” is technically unnecessary when using the original name, much as adding an extra descriptive word to an already specific animal name can be redundant. Nevertheless, “corsac fox” remains the more familiar English expression.

Where Corsac Foxes Live

Corsac foxes are smaller than red foxes and have noticeably paler coats. They inhabit the dry grasslands and open steppe of Central Asia, extending from the Caucasus Mountains eastward toward Manchuria and southward into Afghanistan.

Their habitat preferences help them coexist with red foxes. Corsac foxes generally favor open steppe landscapes, while red foxes are more closely associated with forest edges, woodland, and rougher terrain.

This separation is important because the two species have very similar diets. Both are opportunistic feeders and consume whatever suitable food they can locate, meaning that competition can occur when their ranges overlap.

The Diet of the Corsac Fox

During summer, corsac foxes tend to concentrate more heavily on smaller prey than red foxes do. For example, they consume more beetles and less carrion during this period.

The distinction becomes less pronounced during the severe winter months, when food is harder to obtain and both species become less selective. During winter, corsac foxes also increase their consumption of plant material. In parts of Mongolia, they may even contribute significantly to the dispersal of seeds.

Overall, rodents make up an important part of their diet. In Central Asia, these include mainly ground squirrels, lemmings, gerbils, and wild hamsters.

Corsac foxes also have relatively low water requirements, an especially valuable adaptation in the semi-arid environments where they live.

Snow, Mountains, and Winter Survival

Although corsac foxes can occur at high elevations, they generally prefer relatively flat terrain where they can pursue prey efficiently. They tend to avoid mountainous landscapes.

Snow itself is not necessarily a problem, but hunting becomes difficult when the snow becomes deeper than approximately 15 centimetres, or 6 inches. To deal with this challenge, corsac foxes have sometimes been observed following herds of antelope during winter.

The antelope compact and trample the snow as they move, leaving firmer paths that are easier for the foxes to travel across. This behavior allows corsac foxes to reduce some of the difficulties created by deep snow.

Winter is generally an extremely demanding period for these animals, as it is for many species living in Central Asia. Although corsac foxes are nocturnal and therefore active during the coldest hours of the night, they spend the daylight period sheltered inside dens.

They are capable of digging their own burrows when necessary, but they more commonly make use of abandoned shelters created by other animals, including marmots and badgers.

Social Life and Territory Size

Corsac foxes generally live in pairs and appear to form lifelong mating relationships. During winter, however, several pairs may gather together and share a single den. This suggests that they can be surprisingly tolerant of nearby individuals despite living in relatively independent pairs.

They also appear to be less strongly territorial than red foxes. Corsac foxes scent-mark the area immediately surrounding their den but do not appear to mark large territories extensively.

The size of the area they regularly travel through and hunt in can vary dramatically depending on food availability. When resources are plentiful, their range may be as small as 1 square kilometre, or approximately 250 acres. Under difficult conditions, it can expand to as much as 40 square kilometres, equivalent to about 15 square miles.

How Corsac Fox Populations Cope With Change

The many challenges faced by corsac foxes mean that their population numbers can fluctuate considerably from one year to the next. Weather conditions appear to play a major role, with particularly severe years having a strong effect on their abundance.

At the same time, these foxes generally occupy regions with relatively low human population densities. This may help protect them from some of the pressures that affect wildlife in more heavily populated areas.

Corsac fur was once an important part of the fur trade but is no longer traded as extensively as it was in the past. Although certain regions may still present local threats, the species as a whole appears to be relatively resilient.

Even after periods of heavy harvesting, corsac fox populations have demonstrated an ability to recover. Their adaptability, broad diet, and occupation of remote environments all contribute to their continued survival across the vast grasslands of Central Asia.