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
Species: V. velox
Swift Fox Range
hebes Merriam, 1902
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 (citation needed).
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 the same 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.
The swift fox has a dark, grayish, tan coloration
that extends to a yellowish tan color across its sides and legs.
The throat, chest, and belly range from pale yellow to white in
color. Its tail is black-tipped, and it has black patches on its
muzzle. Its ears are noticeably large. It is about 12 inches (30
cm) in height, and 31 inches (79 cm) long, measuring from the head
to the tip of the tail, or about the size of a domestic cat. Its
weight ranges from around five to seven pounds. Males and females
are similar in appearance, although males are slightly larger.
Habitat and Distribution
The swift fox resides primarily in deserts and short-grass
prairies. They form their dens in sandy soil on open prairies, in
plowed fields, or along fences. It is native to the Great Plains
region of North America, and its range extends north to the central
part of Alberta, Canada, and south to Texas. It reaches from western
Iowa to Colorado, Kansas, Wyoming, Nebraska, and Montana.
The swift fox was once a severely endangered species,
due to predator control programs in the 1930s that were aimed mostly
at the gray wolf and the coyote. The species was extirpated from
Canada by 1938, but a reintroduction program started in 1983 has
been successful in establishing small populations in southeast Alberta
and southwest Saskatchewan, despite the fact that many reintroduced
individuals do not survive their first year. In May 1999, the Species
at Risk Act listed the swift fox as an endangered species in Canada.
Exact population numbers of the swift fox are unknown, but it
is known that they currently inhabit only 40% of their historic
range. In addition to its populations in Canada, there are also
swift fox populations in the United States, ranging from South Dakota
to Texas. In 1995, the U.S. Fish and Wildlife Service determined
that the fox warranted an endangered listing, but other higher priority
species precluded its listing. This prompted state wildlife agencies
within the fox's range to create the Swift Fox Conservation Team,
which worked to implement better swift fox management and monitoring
programs. Populations in the United States are stable in the central
part of its range, and it is not considered endangered in the United
States. The IUCN Red List characterizes it as of Least Concern.
In the wild, the swift fox usually lives 36 years,
but may live up to 14 years in captivity. It is primarily nocturnal,
spending only evenings and nighttime above ground in the summer.
Daytime activities are usually confined to the den, but it has been
known to spend the warm midday period above ground during the winter.
The swift fox is more heavily dependent on its den than most North
American canids, using them as shelter from predators. These dens
are usually underground burrows that are two to four meters in length.
It has been known to run very fast, at speeds of over 50 km/h (30
mph). or up to 60 km/h (40 mph) 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.
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.
Like most canids, the swift fox is an omnivore. Rabbits,
mice, ground squirrels, birds, insects and lizards are staples.
Grasses and fruits round out its diet. However, like any efficient
forager, the swift fox takes advantage of seasonal foods. 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