Swift Fox

The **swift fox** (*Vulpes velox*) is a small light orange-tan fox around the size of a domestic cat found in the western grasslands of North America, such as Montana, Colorado, New Mexico, Oklahoma and Texas. It also lives in Manitoba, Saskatchewan and Alberta in Canada, where it was previously extirpated. It is closely related to the kit fox and the two species are sometimes known as subspecies of *Vulpes velox* because hybrids of the two species occur naturally where their ranges overlap.

The swift fox lives primarily in short-grass prairies and deserts. It became nearly extinct in the 1930s as a result of predator control programs, but was successfully reintroduced later. Currently, the conservation status of the species is considered by the IUCN as Least Concern owing to stable populations elsewhere.

Like most canids, the swift fox is an omnivore, and its diet includes grasses and fruits as well as small mammals, carrion, and insects. In the wild, its lifespan is three to six years, and it breeds once annually, from late December to March, depending on the geographic region. Pups are born anywhere from March to mid-May, and are weaned at six to seven weeks old.

The swift fox is closely related genetically to the kit fox (*Vulpes macrotis*), but occupies a different geographical range. The two have historically been regarded as different species for reasons basically related to size: the kit fox is slightly smaller than the swift fox, and the former has a narrower snout. However, hybrids between the two occur naturally where their ranges overlap, and some mammalogists classify the two as subspecies of a single species, usually treated as *Vulpes velox* (with the swift fox being described as *V. velox velox* and the kit fox as *V. velox macrotis*). The molecular genetics evidence is not conclusive however, and some of those who have used it continue to treat the swift fox and kit fox as separate species.

## Diet

Like most canids, swift foxes eat rabbits, prairie dogs, ground squirrels, mice, birds, reptiles, amphibians, berries and seeds. During the summer, adults eat large amounts of insects, including beetles and grasshoppers, and feed their young with larger prey items. Deer and other carrion killed by other animals may also be important food sources.

## Range and Habitat

The swift fox is native to the Great Plains region of North America. Today the swift fox can be found in fragmented, smaller populations in portions of Montana, South Dakota, Wyoming, Nebraska, Colorado, Kansas, Oklahoma, New Mexico and Texas. Historically, their range included prairies in central North America, extending north to central Alberta, Canada, and south to central Texas, east-west from western Iowa to Colorado, Wyoming and Montana.

## Behavior

They received the name "swift" fox because of their speediness. Swift foxes are nocturnal, vocal and non-territorial. They spend more time underground in their burrows than any other canid. Although they are social animals, they keep one mate throughout their lifetime. The coyote is the swift fox's main predator, but often chooses not to consume the swift fox. Other predators include the badger, golden eagle, and bobcat. It is also vulnerable to trapping and poisoning, as well as death on highways.

### **Reproduction**

The adult swift fox's breeding season varies with region. In the southern United States, it mates between December and February with pups born in March and early April, while in Canada, the breeding season begins in March, and pups are born in mid-May. The male swift fox matures and may mate at one year, while the female usually waits until her second year before breeding. Adults live in pairs, and although some individuals mate for life, others choose different partners each year. Gestation takes around 51 days, and four to five kits are born.

The swift fox only has one litter annually, but may occupy up to thirteen dens in one year, moving because prey is scarce or because skin parasites build up inside the den. Sometimes it makes other burrows from other bigger animals, even though it is completely capable of digging one on its own. Pups are born in the den and typically remain there for approximately one month. A newborn pup's eyes and ears remain closed for ten to fifteen days, leaving it dependent on the mother for food and protection during this time. It is usually weaned around six or seven weeks old and remains with its parents until fall. Recent research has shown that social organization in the swift fox is unusual among canids, since it is based on the females. Females maintain territories at all times, but males emigrate if the resident female is killed or removed.