Reproduction and growth
Foxes breed once a year, mating in June or July. The barking calls of foxes which are often heard during early winter are probably associated with pair formation and the start of courtship. The vixen remains on heat for only three days and gestation lasts about 52 days. Cubs are born during August or September in a dry, sheltered den. They weigh from 100-130g at birth. The average litter size is four. Cubs are fed solid food from about three weeks of age. The dog fox (male parent) assists the lactating vixen by bringing in food for her and the cubs. Cubs are weaned at six to eight weeks of age.
From about four weeks of age the cubs begin to fight among themselves and establish their social ranking. Cubs emerge from the den on a regular basis at about six weeks and usually abandon the den to live on the surface by 10 weeks of age. Young foxes can hunt successfully for small mammals from about 12 weeks of age and most become independent at an age of five to six months. Foxes are capable of breeding when they are about 10 months old.
Mortality is greatest during the first year of life. Many young and inexperienced foxes fall victim to control efforts by humans.
Habits
Foxes hunt alone and for part of the year are basically solitary animals. They become more social as the breeding season approaches, forming or re-establishing pairs. The dog-vixen pair is the basic social group, though groups with additional, non-breeding vixens have been observed. In these larger groups, the vixens have a system of social ranking, with the oldest animal at the top. The younger, subordinate females help the dominant vixen (probably their mother) to raise her latest litter. Juvenile foxes begin to part from their social group at about five to six months of age, eventually dispersing from the area in which they were raised.
Each fox occupies a distinct area called a home range. Home ranges can be from 280-1600ha in size and provide all the needs of a resident fox. Home ranges of individual foxes sometimes overlap. Social groups occupy a group home range, part or all of which may be defended against other foxes; the defended area is termed a territory. The size of home ranges and territories is determined by the density of the fox population and by the availability of food and other resources.
Foxes are active mainly at night. They rest during the day in a den, often an enlarged rabbit burrow, or in sheltered sites such as rock piles, hollow logs, or thickets. A fox may use several resting sites within its home range and does not necessarily return to the same site each day.
In common with many animals, foxes use scent marks as a form of communication. Foxes mark various conspicuous objects within their home ranges with urine, scats (faeces) and secretions from the glands on either side of the anus. These marks can indicate to other foxes that the area is already occupied. Some scent marks may also identify individuals and indicate their sex and reproductive status.
Adaptability and control
Foxes have survived throughout the world despite almost constant attempts by humans to reduce numbers or to eradicate the species. Foxes thrive in many suburban areas and have even adapted to life in the centre of some large cities.
Nevertheless, it is possible in specific areas to protect livestock and native fauna from fox predation. Methods used include exclusion fencing, or the killing of foxes, mostly by baiting and shooting.