Derek Huebner
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Red Fox (Vulpes vulpes)
Vulpes vulpes
Red Fox
DISCRIPTION
The red fox (Vulpes vulpes) is a slender canid distinguished by its red or
yellowish-red coat with white fur on the ventral part of the body (Kurta, 1995). The
black legs and ear tips, as well as the white tip on the black-spotted tail can also be used
to distinguish this species (Lariviere and Pasitschniak-Arts, 1996). In addition to the
common red color phase, there are two rare color morphs, the cross and silver fox, that
are displayed by different individuals (Lariviere and Pasitschniak-Arts, 1996). These
individuals still have the characteristic black legs and a white-tipped tail, but the cross
fox is distinguished by its yellowish to grayish-brown fur and black cross in the shoulder
area (Kurta, 1995). The silver fox can be identified by its silver to black body depending
on the amount of frost-like coloration, which results from the silver tips of guard hairs
(Lariviere and Pasitschniak-Arts, 1996). In Wisconsin, the total length (head, body, and
tail) of an adult red fox ranges from 975-1050 mm (38.4-41.3 in) with an average weight
between 4.1 kg (9 lbs) and 5.9 kg (13 lbs) (Bluett, 1984). The length of the tail, hind
foot, and skull are 300-405 mm (13.0-16.0 in), 160-175 mm (6.3-7.0 in), and 134-156
mm (5.3-6.1 in) respectively (Bluett, 1984). Generally the males have a larger average
size than females (Lariviere and Pasitschniak-Arts, 1996).
DISTIBUTION IN WISCONSIN
Vulpes vulpes is present throughout the entire state (Bluett, 1984). The largest
populations are found in the western, central, and southern parts of the state, while
smaller populations inhabit the widespread forested areas of northern Wisconsin (Bluett,
1984). Historically, the probable distribution of native subspecies of Vulpes vulpes
extended into northern Wisconsin (Kamler and Ballard, 2002). In the mid 1700’s,
European settlers released the nonnative European red fox for sport hunting in the eastern
United States (Kamler and Ballard, 2002). As more nonnative red foxes were released,
the population grew and spread westward into the central part of the United States
(Kamler and Ballard, 2002). Currently, the native species of red fox inhabit areas of
higher elevation, while the nonnative red foxes inhabit agricultural, rangeland, and urban
areas (Kamler and Ballard, 2002). Kamler and Ballard (2002) suggest that the nonnative
red fox has replaced the once native fox of northern Wisconsin and makes up the
widespread population of Vulpes vulpes currently in Wisconsin. Overall, red fox
populations have been relatively high since 1945, but expanding coyote (Canis latrans)
populations may have caused recent numbers to decline (Bluett, 1984).
ONTOGENY AND REPRODUCTION
Vulpes vulpes is a monogamous species, and the male and female pair up in midDecember (Bluett, 1984). Females experience a single estrus period of 1-6 days in
January or February and become sexually receptive for 2-4 days (Bluett, 1984). In
southern Wisconsin, the mean conception dates are January 11-17 (Bluett, 1984). The
gestation period for the red fox is about 53 days, and litter sizes range from 2-10, with the
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Red Fox (Vulpes vulpes)
average Wisconsin litter size being 5.1 pups (Bluett, 1984). Litter size generally
increases with food availability and with age of females (Lariviere and Pasitschniak-Arts,
1996). Pups are 152.4-203.2 mm (6-8 in) long and weigh 99.4-113.6 g (3.5-4.0 ounces)
at birth, and by the time they are weaned, 8-10 weeks later, the pups weigh about 1.6 kg
(3.5 lbs) (Bluett, 1984). Newborn foxes have dark grey fur with whitish brown feet
(Lariviere and Pasitschniak-Arts, 1996). The grey fur changes to a pale buff color at 8-14
days and then changes to red at 9-14 weeks of age (Lariviere and Pasitschniak-Arts,
1996). The eyes of newborn foxes generally do not open until 3 weeks after birth, which
is also around the time pups begin to walk (Lariviere and Pasitschniak-Arts, 1996). Both
of the adults will assist in feeding the pups, and, at about 3 months of age, the juveniles
will start to forage with the adults (Bluett, 1984). At 4-5 months, family bonds begin to
diminish and dispersal usually occurs during October and November (Buett, 1984).
Average juvenile male dispersal (29.6 km/18.4 mi) is greater then the average female
dispersal (10.0 km/6.2 mi) (Buett, 1984). At approximately 10 months, foxes become
sexually mature, with juveniles attaining full reproductive capacity 1-3 weeks after adults
become sexually active (Buett, 1984).
ECOLOGY AND BEHAVIOR
The red fox prefers open areas with edge cover such as brushy fencelines, fieldforest edges, or wooded stream and lake borders (Kurta, 1995). Vulpes vulpes is also
found in residential suburbs, but tend to stay out of industrial and commercial areas
(Lariviere and Pasitschniak-Arts, 1996). Strip cover, pastures, retired croplands, and
hardwoods are all habitats were red fox dens are commonly found (Buett, 1984). Vulpes
vulpes prefer a sand or gravel substrates for den constructions, and often enlarge existing
woodchuck (Marmota monax) or badger (Taxidea taxus) dens (Buett, 1984).
Prey availability plays a very important role in red fox habitat selection (Halpin
and Bissonette, 1988). During winter, shifting snow conditions influence prey
availability, which impacts habitat use and species preyed upon by red foxes (Halpin and
Bissonette, 1988). The red fox is a fairly flexible predator and will prey on mammals,
birds, fish, reptiles, invertebrates, and plants (Bluett, 1984). In southern Wisconsin, the
main prey species of foxes are cottontail rabbits (Sylvilagus floridanus), meadow voles
(Microtus pennsylvanicus), and white-footed mice (Peromyscus spp.) (Ables, 1969).
Since the red fox has such a variable diet, it displays a number of different
hunting behaviors. In Wisconsin, red foxes are nocturnal, and they are most active at
dusk and dawn throughout the year, with reduced relative amounts of nocturnal activity
during the spring and winter (Ables, 1969). The activity patterns of red foxes overlap
with the patterns of their prey, and males will travel an average of 14.5 km (9 mi)
(females-9 km/5.6 mi) a night in search of food (Buett, 1984). When hunting small
mammals, the red fox will use mainly sound to locate individuals and then use an aerial
jump, as high at 4 m (13 ft), to pin the prey to the ground (Lariviere and PasitschniakArts, 1996). Arboreal prey is captured by a quick horizontal thrust, and faster terrestrial
prey is caught by stalking and chasing (Lariviere and Pasitschniak-Arts, 1996). A red fox
will even attempt to nap near a burrow in which prey escaped and wait for it to re-emerge
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Red Fox (Vulpes vulpes)
(Lariviere and Pasitschniak-Arts, 1996). Vulpes vulpes will also cache surplus food, and
mark the caches with urine (Buett, 1984).
The quality of habitat and the availability of food are both factors that affect the
home range size of Vulpes vulpes. In Wisconsin, foxes located in ecologically diverse
habitats will have smaller home ranges (57.5 -161.9 ha/142-400 ac) than foxes in less
diverse areas (up to 5 km2/2 mi2) (Buett, 1984). These home ranges are exclusive with
non-overlapping borders and are actively defended, so they are considered territories
(Lariviere and Pasitschniak-Arts, 1996). These territories are maintained throughout the
year, but individual foxes become more tolerant during denning and rearing periods
(Buett, 1984). Examples of more lenient behavior are: males and females will often share
overlapping areas, territory boundaries far from the den are more flexible, and 2 females
(1 dominant and 1 subordinate) may share the same home range to help raise a litter
(Buett, 1984). Territories are marked with urine, and are aggressively defended by
chases rather then physical contact (Lariviere and Pasitschniak-Arts, 1996).
Along with scent marking and defense of territory, Vulpes vulpes also
communicate through facial expressions and vocalizations (Lariviere and PasitschniakArts, 1996). Urine marking serves as a dominance display, social record, and to mark
remains while scavenging (Lariviere and Pasitschniak-Arts, 1996). Vocalizations are
limited, but simple barking and growling can be used to produce more complex sounds
(Lariviere and Pasitschniak-Arts, 1996). So far, research has show that vocalizations and
facial expressions are secondary to scent marking for maintaining social bonds (Lariviere
and Pasitschniak-Arts, 1996).
The red fox has an average life span of only one year with a few that survive up to
5 or 6 years (Kurta, 1995). In Wisconsin, red foxes are exposed to a number of infectious
diseases including: Leptospira grippotyphosa, canine distemper, canine hepatitis,
staphyloccocus, tularemia, leptospirosis, California encephalitis, and La Crosse
encephalitis (Buett, 1984). From 1967-1968, there was also an epidemic of Sarcoptic
mange that was responsible for roughly 7% of the mortality in southern Wisconsin
(Buett, 1984). Red foxes also carry rabies, but in Wisconsin only 3.1 % of confirmed
rabies cases from 1970-1981 involved foxes (Buett, 1984). Rabies in the red fox is more
of a concern in other parts of the world, and in Ontario, oral rabies vaccine baits are used
to help control rabies (Rosatte, 2002). Heartworms are also know to be carried by foxes,
and can pose a potential threat to domestic dogs (Buett, 1984). One suspected reason for
the local transmission of infectious disease is the fact that communal denning (more than
one family at a den) does take place in about 11% of dens in southern Wisconsin (Buett,
1984). Other causes of mortality include hunting, trapping, and roadkills (Buett, 1984).
LITERATURE CITED
Ables, E.D. 1969. Activity studies of red foxes in southern Wisconsin. The Journal of
Wildlife Management 33:145-153.
Alderton, D. 1998. Foxes, wolves, and wild dogs of the world. Blandford, UK.
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Red Fox (Vulpes vulpes)
Bluett, R. 1984. Red Fox (Vulpes vulpes). Wisconsin Department of Natural Resources
Furbearer Profiles. 7:1-18.
Halpin, M.A., and J.A. Bissonette. 1988. Influence of snow depth on prey availability
and habitat use by red fox. Canadian Journal of Zoology 66:587-592.
Kamler, J.F., and W.B. Ballard. 2002. A review of native and nonnative red foxes in
North America. Wildlife Society Bulletin 30(2):370-379.
Kurta, A. 1995. Red fox: Vulpes vulpes. Pages 208-211 in Mammals of the great lakes
region. The University of Michigan Press, Ann Arbor, Michigan, USA.
Lariviere, S., and M. Pasitschniak-Arts. Mammalian species: Vulpes vulpes. American
Society of Mammalogists 537:1-11.
Rosatte, R.C. 2002. Long distance movement by a coyote, Canis latrans, and red fox,
Vulpes vulpes, in Ontario: Implications for disease-spread. Canadian FieldNaturalist 116(1):129-131.
Reference written by Derek Huebner, Biol 378: Edited by Chris Yahnke.
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