Canid Encyclopedia

Swift Fox

Natural History
The swift fox (Vulpes velox) is considered the smallest canid in North America.  Weighing between 4-6 pounds, these graceful carnivores are the size of a typical house cat.  More commonly known red and gray foxes are considerably larger, weighing 6.5-11 pounds.

Swift foxes are similar in appearance to their close relatives, kit foxes, except they have smaller ears and a broader skull.  They are predominately buff-colored with lighter patches on the throat, chest and belly, and black coloring on either side of the muzzle and at the tip of the tail.

Unlike many canids, the swift fox is almost completely nocturnal and hunts continually from dusk to dawn.  Swift foxes prey on small mammals such as mice, rats, squirrels, and rabbits.  Other prey items include birds, reptiles, amphibians, insects, and occasionally vegetation.

These lone hunters were most likely given their descriptive name because of their ability to outrun certain sure-footed prey species such as jackrabbits. 

Swift foxes form monogamous pairs which remain together throughout most of the year.  They reach sexual maturity at 10 months of age.  Females give birth to kits after a 50-day gestation.  The female gives birth to her young in the safety of a den, which is often an abandoned badger or prairie dog hole.  Litter sizes vary from two to as many as seven.  Male swift foxes play an important role in rearing their offspring by providing food for the denning female and her kits (baby foxes).

Kits emerge from the den at about three weeks of age and soon learn to hunt by taking instructions from their parents.  Kits are usually born between February and April; by fall, young swift foxes are ready to disperse from their parents and strike out on their own.

Distribution and Range
Historically, the range of the swift fox extended southward from central Alberta through the Great Plains to west central Texas.  Habitats selected by swift fox are shortgrass and midgrass prairies with level to gently rolling topography.  In more recent years, some swift foxes have shown the ability to adapt to changing landscapes by denning in cultivated fields and along fence rows.

Both population numbers and distribution of the swift fox have declined in North America since the early 1800s.  The swift fox has been extirpated from two-thirds of its original range and was once completely eliminated from its Canadian range.  Historians believe the swift fox was at one time the most abundant canid in the West and second among mammals in population size only to the prairie dog.

The U.S. population is now restricted to a narrow north-south band cutting across 10 states: Montana, Wyoming, North and South Dakota, Kansas, Nebraska, Oklahoma, Colorado, New Mexico and Texas.

Population Decline
Swift fox populations have declined over the last century from habitat loss and fragmentation, yet the initial decline began in the 1800s as a result of government-sponsored predator control programs and private trapping efforts.  Since the 1950s swift fox populations have stabilized or begun to increase in some areas.

Today, the distribution of the swift fox remains restricted most likely as a result of predation from coyotes, which are now abundant in much of the swift fox’s range.  Swift fox must also compete with other canids, such as red fox and coyote, for available prey.

Captive Breeding and Recovery Efforts
In 1995, the United States Fish and Wildlife Service (USFWS) declared that listing the swift fox as Endangered was warranted but currently precluded by a backlog of higher priority actions.  In lieu of current federal protection, a coalition of ten states to which the swift fox is native formed an organization called the Swift Fox Conservation Team (SFCT).  The SFCT is working to adopt a Conservation Strategy Plan which will involve efforts to protect and expand areas of swift fox distribution, develop methods to monitor wild population status and distribution as well as maintaining a genetically connected continental population.

Implementing cooperative efforts with private landowners and forming conservation agreements with federal land management agencies will be an important step in swift fox recovery.  A captive conservation program for the swift fox has been developed.  Initial steps have begun to develop a formal Species Survival Plan for this species. 

In Canada, where the swift fox had been locally extirpated swift fox reintroduction efforts are underway.  In 1993, the first swift foxes were released in Alberta. 

In 1998, the Endangered Wolf Center received its first pair of swift fox from the Fort Worth Zoo, which has been spearheading captive conservation efforts.