Figure 1. Red fox, Vulpes vulpes (left) and gray fox, Urocyon cinereoargenteus (right)
The red fox (Vulpes vulpes) is the most common of the foxes native to North America. Most depredation problems are associated with red foxes, although in some areas gray foxes (Urocyon cinereoargenteus) can cause problems. Few damage complaints have been associated with the swift fox (V. velox), kit fox (V. macrotis), or Arctic fox (Alopex lagopus).
The red fox is dog-like in appearance, with an elongated pointed muzzle and large pointed ears that are usually erect and forward. It has moderately long legs and long, thick, soft body fur with a heavily furred, bushy tail (Fig. 1). Typically, red foxes are colored with a light orange-red coat, black legs, lighter-colored under fur and a white-tipped tail. Silver and cross foxes are color phases of the red fox. In North America, the red fox weighs about 7.7 to 15.4 pounds (3.5 to 7.0 kg), with males on average 2.2 pounds (1 kg) heavier than females.
Gray foxes weigh 7 to 13 pounds (3.2 to 5.9 kg) and measure 32 to 45 inches (81 to 114 cm) from the nose to the tip of the tail (Fig. 1). The color pattern is generally salt-and-pepper gray with buffy under fur. The sides of the neck, back of the ears, legs, and feet are rusty yellow. The tail is long and bushy with a black tip.
Other species of foxes present in North America are the Arctic fox, swift fox, and kit fox. These animals are not usually associated with livestock and poultry depredation because they typically eat small rodents and lead a secretive life in remote habitats away from people, although they may cause site-specific damage problems.
General Biology, Reproduction, and Behavior
Foxes are crepuscular animals, being most active during the early hours of darkness and very early morning hours. They do move about during the day, however, especially when it is dark and overcast.
Foxes are solitary animals except from the winter breeding season through midsummer, when mates and their young associate closely. Foxes have a wide variety of calls. They may bark, scream, howl, yap, growl, or make sounds similar to a hiccup. During winter a male will often give a yelling bark, “wo-wo-wo,” that seems to be important in warning other male foxes not to intrude on its territory. Red foxes may dig their own dens or use abandoned burrows of a woodchuck or badger. The same dens may be used for several generations. Gray foxes commonly use wood piles, rocky outcrops, hollow trees, or brush piles as den sites. Foxes use their urine and feces to mark their territories.
Mating in red foxes normally occurs from mid-January to early February. At higher latitudes (in the Arctic) mating occurs from late February to early March. Estrus in the vixen lasts 1 to 6 days, followed by a 51- to 53-day gestation period. Fox pups can be born from March in southern areas to May in the arctic zones. Red foxes generally produce 4 to 9 pups. Gray foxes usually have 3 to 7 pups per litter. Arctic foxes may have from 1 to 14 pups, but usually have 5 or 6. Foxes disperse from denning areas during the fall months and establish breeding areas in vacant territories, sometimes dispersing considerable distances.
Figure 2. Range of the red fox in North America.
Figure 3. Range of the gray fox in North America.
Figure 4. Range of the swift fox (dark)and the kit fox (light) in North America.
Red foxes occur over most of North America, north and east from southern California, Arizona, and central Texas. They are found throughout most of the United States with the exception of a few isolated areas (Fig. 2).
Gray foxes are found throughout the eastern, north central, and southwestern United States They are found throughout Mexico and most of the southwestern United States from California northward through western Oregon (Fig. 3).
Kit foxes are residents of arid habitats. They are found from extreme southern Oregon and Idaho south along the Baja Peninsula and eastward through southwestern Texas and northern Mexico (Fig. 4).
The present range of swift foxes is restricted to the central high plains. They are found in Kansas, the Oklahoma panhandle, New Mexico, Texas, Nebraska, South Dakota, Wyoming, and Colorado (Fig. 4). As its name indicates, the Arctic fox occurs in the arctic regions of North America and was introduced on a number of islands in the Aleutian chain.
The red fox is adaptable to most habitats within its range, but usually prefers open country with moderate cover. Some of the highest fox densities reported are in the northcentral United States, where woodlands are interspersed with farmlands. The range of the red fox has expanded in recent years to fill habitats formerly occupied by coyotes (Canis latrans). The reduction of coyote numbers in many sagebrush/grassland areas of Montana and Wyoming has resulted in increased fox numbers. Red foxes have also demonstrated their adaptability by establishing breeding populations in many urban areas of the United States, Canada, and Europe. Gray foxes prefer more dense cover such as thickets, riparian areas, swamp land, or rocky pinyon-cedar ridges. In eastern North America, this species is closely associated with edges of deciduous forests. Gray foxes can also be found in urban areas where suitable habitat exists.
Foxes are opportunists, feeding mostly on rabbits, mice, bird eggs, insects, and native fruits. Foxes usually kill animals smaller than a rabbit, although fawns, pigs, kids, lambs, and poultry are sometimes taken. The fox’s keen hearing, vision, and sense of smell aid in detecting prey. Foxes stalk even the smallest mice with skill and patience. The stalk usually ends with a sudden pounce onto the prey. Red foxes sometimes kill more than they can eat and bury food in caches for later use. All foxes feed on carrion (animal carcasses) at times.
Robert L. Phillips. Wildlife Research Biologist. Denver Wildlife Research Center. USDA-APHIS-Wildlife Services Denver, Colorado. 80225-0266
Robert H. Schmidt. Assistant Professor. Department of Fisheries and Wildlife. Utah State University. Logan, Utah 84322-5210