The Red Fox prefers wooded habitats to open country, but it takes advantage of cropland, urban environments, and sparce, brushy or wooded habitats so long as prey are available. They are nocturnal predators, but their activity may begin as early as two hours before dark, and continue until four hours after dawn. During midday red foxes return to their denning area. They construct their dens during late winter in loose, well-drained soils, often on hillsides in or near heavy brush or woodlands but sometimes in areas as open as cemeteries and parks. Dens may be built by the foxes themselves, or may be enlarged versions of dens previously constructed by other mammals. Dens may have several openings (up to 20 have been recorded), and the tunnels extend one or more meters below ground to a grass-lined nest. Red Foxes are highly mobile, sometimes traveling as much as 10 km in a day, although they normally confine their activities to an area of 8 to 10 square kilometers. After they are bred, females restrict their activities to areas adjacent to the dens, and for several weeks after pups are born, the parents remain within 1 km of the den. During late winter home ranges are larger, presumably because of a decrease in available food.
In the wild, Red Foxes may live as long as 8 or 9 years although a 6-year old is an old fox.
The Red Fox has a varied diet. Rodents and rabbits comprise most of the diet, but Red Foxes also eat fruits, berries, insects, ground nesting birds, and carrion. Coyotes, pumas, bobcats, and domestic dogs are the most important predators on red foxes. Other causes of mortality include trapping, shooting, and highway traffic.
The Red Fox is seasonally monogamous. They potentially breed from December through April, although most matings take place in January and February. After breeding, the female prepares one or more dens within her home range before the young are born. Gestation lasts 52 days, and from 1 to 12 (normally 3 to 6) pups are born with their eyes closed. Their eyes open in about a week. While the pups are young, the male provides food for both them and the female. The young first leave the den at 4 to 5 weeks of age, and they are weaned at 8 to 10 weeks. Usually before weaning the young are moved one or more times to new dens sites. After 10 weeks, pups begin to accompany the parents on hunting trips. At four months, the pups' permanent dentition is present, and they begin to forage for themselves within the parental home range. Young disperse in the autumn when they are nearly adult size. After dispersal in the autumn, Red Foxes are primarily solitary until they pair again in the breeding season.