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Lifespan, longevity, and ageing

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Maximum longevity: 16.2 years (captivity)
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Joao Pedro de Magalhaes
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de Magalhaes, J. P.
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Habitat

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Gray foxes prefer to live in deciduous forests interspersed with brushy, woodland areas. Many populations thrive where woodlands and farmlands meet; however, red foxes (Vulpes vulpes) are known to frequent agricultural areas more than gray foxes. Proximity to water is a key feature of preferred habitat as well. Dens are usually located in hollow trees or logs, in crevices between and under large rocks, and in underground burrows. Dens have also been found in the lower forest canopy, 10 m above the forest floor, in hollow tree trunks and limbs. Gray foxes are the only member of the Canidae family that can climb trees. They are most often found below 3000 m in elevation.

Range elevation: 1000 to 3000 m.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: savanna or grassland ; forest ; scrub forest

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Vu, L. 2011. "Urocyon cinereoargenteus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Urocyon_cinereoargenteus.html
author
Long Vu, University of Michigan-Ann Arbor
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John Berini, Special Projects
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Gail McCormick, Special Projects
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Phil Myers, University of Michigan-Ann Arbor
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Distribution

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Gray foxes are found in the lower half of the Nearctic and northwestern part of the Neotropics. More specifically, their range spans from southern Canada to Venezuela and Columbia, excluding portions of the Great Plains and mountainous regions of northwestern United States and eastern coast of Central America.

Biogeographic Regions: nearctic (Native ); neotropical (Native )

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Vu, L. 2011. "Urocyon cinereoargenteus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Urocyon_cinereoargenteus.html
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Long Vu, University of Michigan-Ann Arbor
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John Berini, Special Projects
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Gail McCormick, Special Projects
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Phil Myers, University of Michigan-Ann Arbor
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Trophic Strategy

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Gray foxes are omnivorous. Although they prey on small vertebrates, fruit and invertebrates also form a substantial part of their diet. Cottontails (Sylvilagus floridanus), mice (Peromyscus), woodrats (Neotoma), and cotton rats (Sigmodon hispidus) form the majority of their winter diet. In the Sonoran Desert, the fruit of the California palm makes up a significant portion of their winter diet. With the onset of spring, fruits become an increasingly important part of their diet, at times making up 70% of its diet. Invertebrates, fruits, nuts, and grains also increase in importance during the spring. Grasshoppers (Orthoptera), beetles (Coleoptera), and butterflies and moths (Lepidoptera) are the preferred invertebrates. When available, gray foxes may also feed on carrion. When gray foxes accumulate an excess amount of food, they cache it by digging a hole with their forepaws and burying it. Immediately afterwards, they mark it with urine or using their scent glands on their paws and tail in an effort to ward off other animals as well as to make it easier to relocate.

Animal Foods: birds; mammals; eggs; carrion ; insects; terrestrial non-insect arthropods

Plant Foods: roots and tubers; seeds, grains, and nuts; fruit

Foraging Behavior: stores or caches food

Primary Diet: carnivore (Eats terrestrial vertebrates, Insectivore , Scavenger ); herbivore (Frugivore , Granivore ); omnivore

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Vu, L. 2011. "Urocyon cinereoargenteus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Urocyon_cinereoargenteus.html
author
Long Vu, University of Michigan-Ann Arbor
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John Berini, Special Projects
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Gail McCormick, Special Projects
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Phil Myers, University of Michigan-Ann Arbor
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Associations

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Gray foxes have a small, but important role in our ecosystems. Their feeding habits allow them to influence small rodent (Rodentia) populations by maintaining a steady predator-prey relationship. They serve as a host to many parasitic arthropods, including fleas (Siphonaptera), lice (Phthiraptera), ticks (Ixodida), chiggers (Trombidiformes), and mites (Acari). Gray foxes are also host to a number of internal parasites including nematodes (Nematoda), flukes (Trematoda), tapeworms (Cestoda), and acanthocephalans (acanthocephala)

Commensal/Parasitic Species:

  • nematodes (Nematoda)
  • flukes (Trematoda)
  • tapeworms (Cestoda)
  • acanthocephalans (acanthocephala)
  • fleas (Siphonaptera)
  • lice (Phthiraptera)
  • ticks (Ixodida)
  • chiggers (Trombidiformes)
  • mites (Acari)
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Vu, L. 2011. "Urocyon cinereoargenteus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Urocyon_cinereoargenteus.html
author
Long Vu, University of Michigan-Ann Arbor
editor
John Berini, Special Projects
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Gail McCormick, Special Projects
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Phil Myers, University of Michigan-Ann Arbor
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Benefits

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Gray foxes are hunted and trapped for their pelt. Compared to red fox (Vulpes vulpes), gray fox pelts are less desirable because the hairs are coarser and shorter. Gray foxes may also help control the abundance of certain agricultural pests, including rodents (Rodentia) and rabbits (Leporidae).

Positive Impacts: body parts are source of valuable material; controls pest population

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Vu, L. 2011. "Urocyon cinereoargenteus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Urocyon_cinereoargenteus.html
author
Long Vu, University of Michigan-Ann Arbor
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John Berini, Special Projects
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Gail McCormick, Special Projects
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Phil Myers, University of Michigan-Ann Arbor
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Benefits

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Gray foxes are considered a problem species by poultry farmers. However, red foxes (Vulpes vulpes) are commonly misidentified as gray foxes, and commonly attack and kill poultry as well. In addition, gray foxes carry zoonotic diseases that could be a potential health threat to humans (e.g., rabies) and domestic dogs (Canis lupus familiaris; e.g., tularemia and canine distemper).

Negative Impacts: injures humans (causes disease in humans , carries human disease); causes or carries domestic animal disease

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Vu, L. 2011. "Urocyon cinereoargenteus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Urocyon_cinereoargenteus.html
author
Long Vu, University of Michigan-Ann Arbor
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John Berini, Special Projects
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Gail McCormick, Special Projects
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Phil Myers, University of Michigan-Ann Arbor
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Conservation Status

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Gray foxes are abundant throughout most areas in the lower two-thirds of North America. They have no special conservation status at this time. Although they are trapped and hunted by humans, there does not appear to be any immediate threat.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

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Vu, L. 2011. "Urocyon cinereoargenteus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Urocyon_cinereoargenteus.html
author
Long Vu, University of Michigan-Ann Arbor
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John Berini, Special Projects
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Gail McCormick, Special Projects
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Phil Myers, University of Michigan-Ann Arbor
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Behavior

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Like other members of the family Canidae, gray foxes are able to communicate by barking and growling. Males have been observed trying to attract potential mates by raising their hind leg to show off their genitalia. As juveniles, gray foxes commonly play fight. As adults, they use their scent glands to mark territories and food sources.

Communication Channels: tactile ; acoustic ; chemical

Other Communication Modes: pheromones ; scent marks

Perception Channels: visual ; tactile ; acoustic ; chemical

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Vu, L. 2011. "Urocyon cinereoargenteus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Urocyon_cinereoargenteus.html
author
Long Vu, University of Michigan-Ann Arbor
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John Berini, Special Projects
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Gail McCormick, Special Projects
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Phil Myers, University of Michigan-Ann Arbor
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Life Expectancy

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Lifespan for both captive and wild gray foxes ranges from 6 to 8 years. However, the oldest recorded wild gray fox was 10 years old at time of capture, and the oldest captive gray fox lived to be 12 years old.

Gray foxes generally live for 6 to 8 years. The oldest wild gray fox was 10 years old when captured. The oldest gray fox in captivity lived to be 12 years old.

Range lifespan
Status: wild:
6 to 10 years.

Range lifespan
Status: captivity:
6 to 12 years.

Typical lifespan
Status: wild:
6 to 8 years.

Typical lifespan
Status: captivity:
6 to 8 years.

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bibliographic citation
Vu, L. 2011. "Urocyon cinereoargenteus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Urocyon_cinereoargenteus.html
author
Long Vu, University of Michigan-Ann Arbor
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John Berini, Special Projects
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Gail McCormick, Special Projects
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Phil Myers, University of Michigan-Ann Arbor
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Morphology

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Fully grown gray foxes display a mix of white, red, black and gray fur. However, new born pups tend to be dark brown. Gray foxes are medium-sized canids with elongated bodies and relatively short legs. They usually weigh between 3 and 5 kg, but can weigh up to 9 kg. Individuals at high elevation are slightly larger than their low elevation counterparts. Males are slightly larger than females, and skeletal measurements show that males have longer pelvises and calcanea, wider scapulae and more robust limb bones. In general, gray foxes can grow up to 1 m in length. Their tail makes up approximately one-third of their total body length and has a distinct black stripe along the dorsal surface and a black tip. The top of the head, back, sides, and rest of the tail are gray with the belly, chest, legs and sides of the face being reddish brown. The cheeks, muzzle and throat are white. Gray foxes have oval-shaped pupils and the area around the eyes has a thin black stripe from the outside corner of the eye to the side of the head. Additionally, a thick black stripe runs from the inside corner of the eye, down the muzzle to the mouth. They are sometimes misidentified as red foxes (Vulpes vulpes); however, red foxes have slit-shaped eyes, larger feet, longer legs, and a leaner body.

Range mass: 2 to 9 kg.

Range length: 800 to 1125 mm.

Average length: 1000 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger

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bibliographic citation
Vu, L. 2011. "Urocyon cinereoargenteus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Urocyon_cinereoargenteus.html
author
Long Vu, University of Michigan-Ann Arbor
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John Berini, Special Projects
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Gail McCormick, Special Projects
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Phil Myers, University of Michigan-Ann Arbor
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Associations

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Gray foxes primary predators include bobcats (Lynx rufus), golden eagles (Aquila chrysaetos), great-horned owls (Bubo virginianus) and coyotes (Canis latrans). In the southern region of the United States, gray fox abundance is highly dependent on coyote abundance. Other than death by natural causes, humans may be responsible for the greatest number of deaths and therefore may be their largest threat. Hunting, trapping and retaliatory killings by livestock ranchers are not uncommon. Unlike red foxes (Vulpes vulpes), which evade predators by using their superior agility, gray foxes escape by hiding under cover (e.g., brush piles). When escaping terrestrial predators, gray foxes can use their retractable claws to climb trees.

Known Predators:

  • coyote (Canis latrans)
  • bobcat (Lynx rufus)
  • golden eagle (Aquila chrysaetos)
  • great horned owl (Bubo virginianus)
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bibliographic citation
Vu, L. 2011. "Urocyon cinereoargenteus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Urocyon_cinereoargenteus.html
author
Long Vu, University of Michigan-Ann Arbor
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John Berini, Special Projects
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Gail McCormick, Special Projects
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Phil Myers, University of Michigan-Ann Arbor
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Reproduction

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Gray foxes are solitary animals that socialize only during mating season. They are typically monogamous, although in rare cases polygamy and polyandry occur. For a short period of time after parturition, family groups consisting of male, female, and young exist. Male-female pairings form in the fall with breeding occurring in the winter. During October and September, attracting mates become more competitive and males usually display more aggression while retaining and defending mates. Similar to domestic dogs (Canis lupus familiaris), gray foxes have scent glands just inside the anus. Additional scent glands are found on their face and the pads of their feet. Although these glands are primarily used to demarcate territory, they may also be used to attract potential mates.

Mating System: monogamous

Breeding season varies with geographic region, elevation, and habitat quality. Breeding occurs in yearly cycles, beginning in January through late February, continuing into March. In some areas (e.g., Texas), breeding has been observed as early as December. Parturition occurs after about 2 months of gestation, peaking in April, with an average litter size of 3.8 pups, which weigh about 86 g at birth. Pups are typically weaned by 3 to 4 weeks, but may not be completely weaned until 6 weeks. Both genders are sexually mature by 10 months old, soon after dispersal. Annual onset of spermatogenesis occurs earlier and last longer than estrus. If they have been exposed to significant levels of the synthetic estrogen, diethylstilbestrol, females may experience delayed fertilization.

Breeding interval: Gray foxes breed once yearly.

Breeding season: December through March.

Range number of offspring: 1 to 7.

Average number of offspring: 3.8.

Range gestation period: 53 to 63 days.

Average gestation period: 59 days.

Range weaning age: 2 to 6 weeks.

Range time to independence: 10 to 17 months.

Average time to independence: 12 months.

Average age at sexual or reproductive maturity (female): 10 months.

Average age at sexual or reproductive maturity (male): 10 months.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous

Average birth mass: 95 g.

Average number of offspring: 4.

Average age at sexual or reproductive maturity (male)
Sex: male:
365 days.

Average age at sexual or reproductive maturity (female)
Sex: female:
345 days.

Both genders take care of offspring in gray foxes. Before birth, males do a majority of the hunting, while females look for and prepare a suitable den. Weaning begins around 2 to 3 weeks of age. Pups begin eating solid food around 3 weeks old, which is primarily provided by the father. Parents teach pups how to hunt at around 4 months old. Until then, both parents prey for food separately, and pups practice their hunting skills by pouncing and stalking, which is primarily taught by the father. Pups depend on their parents for defense until about 10 months old, at which point they become sexually mature and disperse.

Parental Investment: precocial ; male parental care ; female parental care ; pre-hatching/birth (Provisioning: Male); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)

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Vu, L. 2011. "Urocyon cinereoargenteus" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Urocyon_cinereoargenteus.html
author
Long Vu, University of Michigan-Ann Arbor
editor
John Berini, Special Projects
editor
Gail McCormick, Special Projects
editor
Phil Myers, University of Michigan-Ann Arbor
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Associated Plant Communities

provided by Fire Effects Information System Animals
More info for the terms: forest, grassland

Common gray foxes occur in a wide variety of forest types; they prefer
woodlands and woodland-brush ecotones over open habitat.  They commonly
occur in eastern and southwestern deciduous forests, but are also found
in mixed and coniferous forests of the northeastern and western states [36].

Common gray foxes are ecologically important members of the oak (Quercus
spp.)-hickory (Carya spp.) ecosystem.  In the Missouri Ozarks mature
oak-hickory stands were the most frequently used (of six habitat types)
by common gray foxes, both at night and during the day.  Old fields were least
used [18].  In North Carolina common gray fox habitats include evergreen redbay
(Persea borbonia) forests, deciduous forests, and streamhead forests.
Common gray foxes were common in the most densely wooded habitats, including
pocosins.  They are often seen running along sandy rims and ridges
between bay and streamhead forests [5].  In central Louisiana common gray foxes
occur in longleaf pine (Pinus palustris)-slash pine (P. elliottii)
stands [25].  Common gray foxes are common in southwestern Wisconsin
oak-hickory forests dominated by white oak (Q. alba), northern red oak
(Q. rubra), black oak (Q. velutina), and shagbark hickory (C. ovata)
with lesser amounts of white ash (Fraxinus americana), green ash (F.
pennsylvanica), maples (Acer spp.), and basswood (Tilia americana) [33].

In Zion National Park, Utah, common gray foxes occur in blackbrush (Coleogyne
ramosissima), shrub-grassland dominated by fourwing saltbush (Atriplex
canescens), and pinyon (Pinus spp.)-juniper (Juniperus spp.) [35].  In
Texas common gray foxes are found in post oak (Q. stellata) woodlands,
pinyon-juniper woodlands, and wooded sections of shortgrass prairie.  In
western states common gray foxes are found in brushy habitat, woods, and
chaparral [36].  In Arizona common gray foxes are relatively rare; they are
typically found in pine (Pinus spp.)-Gambel oak (Q. gambelii) woodlands
at 5,000 to 6,000 feet (1,500-1,800 m) elevation.  They also occur in
pine-fir (Abies spp.), ponderosa pine (P. ponderosa), chaparral, and
desert grassland habitats [6,31].  In California common gray foxes are most
common in mature chaparral at elevations of 1,000 to 3,000 feet (300-900
m) and also occur in open chaparral, riparian areas, and other plant
communities [29].  In riparian zones they have been found in communities
dominated by Fremont cottonwood (Populus fremontii)-northern California
black walnut (Juglans californica var. hindsii), and by large willow
(Salix laevigata) [17].  In northwestern California common gray foxes were
present in Douglas-fir (Pseudotsuga menziesii) forests [39].
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Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Common Names

provided by Fire Effects Information System Animals
More info for the term: tree

common gray fox
grey fox
tree fox
maned fox
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bibliographic citation
Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Conservation Status

provided by Fire Effects Information System Animals
Information on state- and province-level protection status of animals in the
United States and Canada is available at NatureServe, although recent changes
in status may not be included.
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bibliographic citation
Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Cover Requirements

provided by Fire Effects Information System Animals
More info for the terms: cover, tree

Common gray foxes tend to escape their enemies by finding cover rather than
depending on speed (as do red foxes) [23].  Dense vegetation is
important as diurnal resting and escape cover [18].  They climb trees
for use as resting and escape cover [23].  Their climbing ability
extends to saguaro (Carnegiea gigantea); one common gray fox was observed
resting 15 feet (4.6 m) above ground on a saguaro limb [6].

Den sites include hollow logs and trees, rock outcrops, underground
burrows (usually the abandoned den of some other species), cavities
under rocks, abandoned buildings, wood or sawdust piles, and brush
[9,23].  Dens have been found up to 20 feet (9.1 m) above ground in tree
hollows.  Underground dens have usually been excavated by animals of
other species, but common gray foxes occasionally dig dens in loose soil [35].

Den Use:  Dens are used throughout the year, but primary use is during
whelping season.  Dens are usually located in brushy or wooded habitats.
In Wisconsin most common gray fox dens were on east-, southeast-, or
south-facing slopes [9].  Leaves, grass, fur, and other soft materials
are added to dens [23].
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bibliographic citation
Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Distribution

provided by Fire Effects Information System Animals
The range of common gray fox extends from extreme southern Canada to northern
Venezuela and Columbia, excluding portions of the northern Rocky
Mountain region, the northern Great Plains, and eastern Central America
[16].  Common gray fox range has expanded in the last 50 years to areas
formerly unoccupied and areas where common gray fox had been extirpated
including New England, Michigan, Minnesota, Iowa, Ontario, Manitoba,
North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, and Utah [9].

Ranges of subspecies follow [16].

U. c. borealis occurs in New England and southern Ontario.

U. c. californicus occurs from southwestern California to northern Baja
California.

U. c. cinereoargenteus occurs from southern Massachusetts and
Connecticut west to Lake Michigan and Illinois; south to central South
Carolina; and west to the Mississippi River.

U. c. floridanus occurs from southern South Carolina south to Florida
and west to eastern Texas; it occurs along the Gulf Coast excluding
Louisiana.

U. c. ocythous occurs in Wisconsin and extreme western Illinois; from
Missouri and Arkansas west to Oklahoma, Kansas, Nebraska, South Dakota,
North Dakota, and extreme southern Manitoba and Quebec.

U. c. scottii occurs from western Texas north through northern Colorado
and Utah to the southern half of Nevada; and from California east of the
Sierra Nevada southeast in Mexico to Chihuahua.

U. c. townsendi occurs in northern California and western Oregon.
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bibliographic citation
Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Food Habits

provided by Fire Effects Information System Animals
More info for the term: fruit

Common gray foxes are omnivorous, opportunistic feeders; they prey mainly on
small mammals, but fruit and invertebrates form a substantial portion of
the diet.  In the central United States cottontails (Sylvilagus spp.)
formed the major portion of the common gray fox winter diet.  Other mammals
taken in noticeable numbers include voles (Microtus spp.), mice
(Peromyscus spp.), woodrats (Neotoma spp.), and cotton rats (Sigmodon
spp.).  Invertebrates increase in importance in the spring.  With
seasonally advancing vegetative growth and development, plant material,
particularly fruit, increases in common gray fox diets, sometimes comprising up
to 70 percent by volume [10].  Grasshoppers (Orthoptera), beetles
(Coleoptera), and butterflies and moths (Lepidoptera) are the preferred
invertebrates; plant materials include fruits, nuts, grains, and
grasses.  Carrion is eaten opportunistically [35].  In some areas birds
(nestlings and eggs), particularly ground-nesters, are taken by common gray
foxes; in Texas wild turkey (Meleagris gallopavo) nests were broken up
by common gray foxes [3].

In a riparian area in the Central Valley of California, a common gray fox ate
mostly ring-necked pheasant (Phasianus colchicus), California ground
squirrels (Spermophilus beecheyi), California voles (Microtus
californicus), and berries [11].  In Oregon primary prey items include
mice, pocket gophers (Thomomys and Geomys spp.), kangaroo rats
(Dipodomys spp.), woodrats, ground squirrels (Spermophilus spp.),
chipmunks (Tamias spp.), brush rabbit (Sylvilagus bachmanii), and birds
including domestic poultry.  Other food items include grasshoppers,
beetles, manzanita (Arctostaphylos spp.) berries, juniper cones, and
cascara (Rhamnus purshiana) berries [23].  In the Sonoran Desert the
fruit of the California palm (Washingtonia filifera) forms a substantial
portion of the common gray fox winter diet [2].  In eastern Tennessee plant
foods included persimmon (Diospyros virginiana), black cherry (Prunus
serotina), blackberry (Rubus spp.) , and cancerroot (Conophilus
americana).  The most common vertebrate prey determined in scat analysis
(by volume) was eastern cottontail (Sylvilagus floridana), followed by
white-tailed deer (Odocoileus virginiana), presumably as carrion, and
rodents [14].
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bibliographic citation
Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Habitat-related Fire Effects

provided by Fire Effects Information System Animals
More info for the terms: cover, fruit, shrub

Common gray foxes use brush and brushy woods in most areas.  Fire that reduces
brush cover will decrease common gray fox habitat.  Fire usually increases the
productivity of early successional prey species and improves predator
efficiency by reducing hiding cover for prey [21].  In the Southeast
fire produces immediate short-term habitat reduction for prey animals;
prey is concentrated in unburned habitat islands [19].  The most
important common gray fox prey in the Southeast are cottontails and cotton
rats.  Cottontails and cotton rats are not usually killed by fire but
prefer habitats with more cover than is found in immediate postfire
environments.  Both species return to postfire habitats when there is
sufficient vegetation for food and cover.  Fire often reduces fruit
production in the short term, but edges of older burns are usually good
regeneration sites for fruiting shrub species such as blackberries and
blueberries (Vaccinium spp.); gallberry (Ilex glabra) produces the most
fruit a few years after fire pruning [21].
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Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Habitat: Cover Types

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

More info for the terms: cover, cover type

   The common gray fox occurs in nearly every SAF cover type.
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Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Habitat: Ecosystem

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

More info for the term: shrub

FRES10 White-red-jack pine
FRES11 Spruce-fir
FRES12 Longleaf-slash pine
FRES13 Loblolly-shortleaf pine
FRES14 Oak-pine
FRES15 Oak-hickory
FRES16 Oak-gum-cypress
FRES17 Elm-ash-cottonwood
FRES18 Maple-beech-birch
FRES19 Aspen-birch
FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES23 Fir-spruce
FRES24 Hemlock-Sitka spruce
FRES26 Lodgepole pine
FRES27 Redwood
FRES28 Western hardwoods
FRES29 Sagebrush
FRES30 Desert shrub
FRES31 Shinnery
FRES32 Texas savanna
FRES33 Southwestern shrubsteppe
FRES34 Chaparral-mountain shrub
FRES35 Pinyon-juniper
FRES36 Mountain grasslands
FRES37 Mountain meadows
FRES38 Plains grasslands
FRES39 Prairie
FRES40 Desert grasslands
FRES41 Wet grasslands
FRES42 Annual grasslands
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Habitat: Plant Associations

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the term: association

   The common gray fox occurs in nearly every Kuchler plant association.
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Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Habitat: Rangeland Cover Types

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This species is known to occur in association with the following Rangeland Cover Types (as classified by the Society for Range Management, SRM):

More info for the term: cover

   The common gray fox occurs in most SRM cover types.
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Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Management Considerations

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Common gray fox pelts are of some value but are not as valued as those of red
fox [23].  Trapping increases and decreases with pelt values; in a 1987
report it was mentioned that sales in the United States had increased
dramatically in the last decade.  The common gray fox has "furbearer"
management status in many states [13,38].

Population Status:  The common gray fox is characterized by widespread, healthy
populations in most areas.  Habitat availability may limit its
distribution, but lack of habitat does not appear to pose an immediate
threat [13].  Common gray foxes are uncommon to common in New England [7].
Reported population densities range from 1 to 27 per square mile [35].

Common gray foxes are considered pests by many farmers who raise domestic
poultry; biologists claim that this damage is usually overstated and
that common gray foxes benefit agriculture by controlling rodent and rabbit
populations [23].  In northern bobwhite (Colinus virginianus) management
areas only a small number of common gray foxes (0.7%) were found to have
northern bobwhite remains in their stomachs [26].

Common gray foxes commonly carry rabies, most frequently in the Appalachian
states (KY, TN, VA, WV) [4].  They also carry tularemia [23] and canine
distemper which is not as virulent in common gray foxes as it is in domestic
dogs (Canis familiaris) [38].
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Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Occurrence in North America

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AL
AZ
AR
CA
CO
CT
DE
FL
GA
IL

IN
IA
KS
KY
LA
ME
MD
MA
MI
MN

MS
MO
NE
NV
NH
NJ
NM
NY
NC
ND

OH
OK
OR
PA
RI
SC
SD
TN
TX
UT

VT
VA
WV
WI
WY

MB
ON
PQ
MEXICO

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Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Predators

provided by Fire Effects Information System Animals
Adult common gray foxes have few predators, but are occasionally taken by
golden eagle (Aquila chrysaetos), coyote (Canis latrans), and bobcat
(Lynx rufus) [35]; pups are taken by bobcat, great horned owl (Bubo
virginianus), and possibly large hawks [23].
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Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Preferred Habitat

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More info for the terms: forest, hardwood, shrub

Common gray foxes are most closely associated with deciduous forest,
particularly where it is in contact with disturbed or brushy habitat
[9,23,35].  They are usually found near surface water [29].  Preferred
habitat includes shrublands and brushy woodlands on hilly or rough
terrain.  In areas where common gray foxes and red foxes occur together, common gray
foxes prefer mixed woods with dense underbrush.  In the absence of red
foxes, common gray foxes prefer other habitats [35].

In New England common gray foxes are associated with dense northern hardwood or
mixed forests, thickets, and swamps.  Preferred habitat includes a
mixture of fields and woods [7].  In Wisconsin common gray foxes were most
abundant near brush-covered bluffs where woods and farmland were well
interspersed [28].  From Virginia to southern Georgia optimal common gray fox
habitat consists of woodland-farmland edge; post oak woodlands are also
good common gray fox habitat [9].  In southern Georgia common gray foxes are most
abundant in mixed woods and cultivated areas, less abundant in pine
savanna, and least common in mixed woods with dense underbrush [35].  On
the Coastal Plain most common gray fox captures occurred in tall
weed-broomsedge (Andropogon virginicus)-dominated habitats and
cultivated areas.  There were relatively few captures on forested sites;
this difference from common gray fox preferences in the majority of its range
was attributed to the absence of red foxes [24].

In the western states common gray fox habitats include rocky hillsides,
mountainsides, and washes [35].  In Oregon common gray foxes prefer mixed
hardwood and mixed conifer-hardwood habitats; they are present in
riparian hardwood, headland prairie, headland shrub, and tanoak
(Lithocarpus densiflorus) habitats [23].  In the Central Valley of
California, one common gray fox spent most of its time in old fields and
human-use areas, one spent most of its time in agricultural areas, and
two spent most of their time in riparian areas.  None of the foxes used
areas of open dirt [11].  In California common gray foxes were most abundant
from 3,800 to 5,000 feet (1,150-1,525 m) elevation [15].  In
northwestern California Douglas-fir forests, common gray foxes were present in
similar abundances in all forest seres, but there were slightly fewer
common gray foxes in mature timber [39].

Home Range:  Common gray foxes tracked from May through August, 1980 and
January through August, 1981, had a monthly average home range of 740
acres (299 ha), and an average composite home range of 1,700 acres (676
ha).  Some individuals occupied the same general area for extended
periods, but home ranges tended to shift from month to month.  Only a
fraction of the home range is used on a given night [18].  The composite
home ranges of four radio-tracked common gray foxes varied from 262 to 425
acres (106-172 ha).  Common gray foxes are apparently solitary in the
nonbreeding seasons [17].  In Wisconsin common gray fox home ranges vary from
0.24 to 1.2 miles (0.40-2 km) in diameter [32].  Lord [22] estimated
common gray fox home range diameter of 1.9 miles (3.2 km).  Trapp [34] reported
an annual home range average of 0.2 square mile (0.52 sq km).

Territoriality:  Common gray fox territoriality is not well defined.
Territories are marked with urine and feces, but in many areas home
ranges overlap considerably.  Family aggregates are formed so that
individual territories overlap; family aggregates do not overlap [18].
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Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Regional Distribution in the Western United States

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This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

    1  Northern Pacific Border
    2  Cascade Mountains
    3  Southern Pacific Border
    4  Sierra Mountains
    6  Upper Basin and Range
    7  Lower Basin and Range
    9  Middle Rocky Mountains
   10  Wyoming Basin
   11  Southern Rocky Mountains
   12  Colorado Plateau
   13  Rocky Mountain Piedmont
   14  Great Plains
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Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Taxonomy

provided by Fire Effects Information System Animals
The currently accepted scientific name of common gray fox is Urocyon
cinereoargenteus Schreber. It is a member of the dog family (Canidae).
There are 15 accepted subspecies; the 7 subspecies occurring north of
Mexico are as follows [16]:

Urocyon cinereoargenteus borealis Merriam
Urocyon cinereoargenteus californicus Mearns
Urocyon cinereoargenteus cinereoargenteus (Schreber)
Urocyon cinereoargenteus floridanus Rhoads
Urocyon cinereoargenteus ocythous Bangs, prairie gray fox
Urocyon cinereoargenteus scottii Mearns
Urocyon cinereoargenteus townsendi Merriam
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Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Timing of Major Life History Events

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More info for the terms: cover, litter

Diurnal Activity:  Common gray foxes are more active at night and at dusk than
during the day.  Activity levels decrease sharply at sunrise, and
increase at sunset [17,18].  Common gray foxes usually leave their daytime rest
area shortly before sunset, investigate the immediate area, and then
move purposefully to a foraging area.  Close to sunrise they usually
move back to a daytime resting area.  Common gray foxes usually change resting
sites every day once vegetative cover is abundant in late spring; sites
are reused in winter [17].

Breeding Season:  Common gray foxes usually breed from late winter to early
spring; dates of mating activity vary with latitude and elevation.  In
southern Illinois breeding occurs from late January to February; in
Wisconsin breeding occurs from late January to March [9], and in Oregon
mating occurs from mid-February to March [23].  Where common gray fox is
sympatric with red fox (Vulpes vulpes), common gray foxes breed 2 to 4 weeks
later than red foxes.  Common gray foxes are assumed to be monogamous, but
direct evidence is lacking [9].  There is only one litter per year [35].

Gestation and Development of Young:  Gestation periods have been
variously reported as ranging from 53 to 63 days; Fritzell [10] reported
gestation in captivity lasted 59 days.  Mean litter size is 3.8, ranging
from 1 to 7.  Development has not been well studied [9].  Young are born
blind and nearly naked.  Eyes open about 9 days after birth.  The pups
nurse for over 3 weeks.  Solid food is fed to the pups before they are
completely weaned with the male beginning to bring food to the pups at
about 2 to 3 weeks.  Pups begin to fend for themselves at about 3
months; families disperse in late summer and autumn [23].

Population Structure:  Root and Payne [33] determined that the majority
of animals in a southwestern Wisconsin common gray fox population were under 1
year old.  They concluded that common gray foxes are "an annual crop."  The
majority of female common gray foxes breed their first year [33].

Mortality and Longevity:  In the Central Valley of California, two of
four radiotracked common gray foxes were killed by cars [11].  In east-central
Alabama, a population of common gray foxes was tagged and monitored for causes
of mortality.  Canine distemper was the most frequent cause of death,
followed by trapping, automobile collision, and infectious canine
hepatitis.  Canine distemper was probably a localized cause of mortality
in this area; it is not expected that most common gray fox populations suffer
the same rate of distemper deaths [27].  Maser and others [23] stated
that collision with automobiles is rare in Oregon; the major causes of
common gray fox mortality are hunting and trapping.  They listed a probable
maximum longevity in the wild of 6 years.  The oldest captive common gray fox
lived less than 8 years [23].
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Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

U.S. Federal Legal Status

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Urocyon cinereoargenteus ocythous is Under Review for listing [40].
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Use of Fire in Population Management

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Hon [19] and Landers [21] suggest that in the Southeast, burning fields
and slash pine forests on 3-year rotations would create desirable
furbearer habitat; areas supporting fire-sensitive fruit-bearing plants
should be protected from fire.

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".
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Gray fox

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The gray fox (Urocyon cinereoargenteus), or grey fox, is an omnivorous mammal of the family Canidae, widespread throughout North America and Central America. This species and its only congener, the diminutive island fox (Urocyon littoralis) of the California Channel Islands, are the only living members of the genus Urocyon, which is considered to be genetically basal to all other living canids. Its species name cinereoargenteus means "ashen silver".

It was once the most common fox in the eastern United States, and though still found there, human advancement and deforestation allowed the red fox to become the predominant fox-like canid. Despite this post-colonial competition, the gray fox has been able to thrive in urban and suburban environments, one of the best examples being southern Florida.[2][3] The Pacific States and Great Lakes region still have the gray fox as their prevalent fox.[4][5][6]

Etymology

The genus Urocyon comes from the Latin 'uro' meaning tail, and 'cyon', meaning dog. The species epithet cinereoargenteus is a combination of 'cinereo' meaning ashen, and 'argenteus' (from argentum), meaning 'silver', referencing the color of the tail.

Description

The gray fox is mainly distinguished from most other canids by its grizzled upper parts, black stripe down its tail and strong neck, ending in a black-tipped tail, while the skull can be easily distinguished from all other North American canids by its widely separated temporal ridges that form a ‘U’-shape. Like other canids, the fox's ears and muzzle are angular and pointed. Its claws tend to be lengthier and curved.

There is little sexual dimorphism, save for the females being slightly smaller than males. The gray fox ranges from 76 to 112.5 cm (29.9 to 44.3 in) in total length. The tail measures 27.5 to 44.3 cm (10.8 to 17.4 in) of that length and its hind feet measure 100 to 150 mm (3.9 to 5.9 in). The gray fox typically weighs 3.6 to 7 kg (7.9 to 15.4 lb), though exceptionally can weigh as much as 9 kg (20 lb).[7][8][9][10] The grey fox is readily distinguished from the red fox by its obvious lack of the "black stockings" that stand out on the red fox. The grey fox has a stripe of black hair that runs along the middle of its tail, and individual guard hairs that are banded with white, gray, and black.[11] The gray fox displays white on the ears, throat, chest, belly, and hind legs.[11] Gray foxes also have black around their eyes, on the lips, and on their noses.[12]

Gray fox, showing black tail stripe, Sierra Nevada

In contrast to all Vulpes and related (Arctic and fennec) foxes, the gray fox has oval (instead of slit-like) pupils.[13](p122) The gray fox also has reddish coloration on parts of its body, including the legs, sides, feet, chest, and back and sides of the head and neck.[10] The stripe on the fox's tail ends in a black tip as well.[14] Their weight can be similar to that of a red fox, but gray foxes appear smaller because their fur isn't as long and they have shorter limbs.[15]

The dental formula of the U. cinereoargenteus is 3.1.4.23.1.4.3 = 42.[11]

Origin and genetics

Gray fox kit at the Palo Alto Baylands in California

The gray fox appeared in North America during the mid-Pliocene (Hemphillian land animal age) epoch 3.6 million years ago (AEO) with the first fossil evidence found at the lower 111 Ranch site, Graham County, Arizona with contemporary mammals like the giant sloth, the elephant-like Cuvieronius, the large-headed llama, and the early small horses of Nannippus and Equus.[16] Faunal remains at two northern California cave sites confirm the presence of the gray fox during the late Pleistocene.[17] Genetic analysis has shown that the gray fox migrated into the northeastern United States post-Pleistocene in association with the Medieval Climate Anomaly warming trend.[18]

Genetic analyses of the fox-like canids confirmed that the gray fox is a distinct genus from the red foxes (Vulpes spp.). The genus Urocyon is considered to be the most basal of the living canids.[19] Genetically, the gray fox often clusters with two other ancient lineages: The east Asian raccoon dog (Nyctereutes procyonoides) and the African bat-eared fox (Otocyon megalotis).[20]

The chromosome number is 66 (diploid) with a fundamental number of 70. The autosomes include 31 pairs of sub-graded subacrocentrics, but one only pair of metacentrics.[21]

Recent mitochondrial genetic studies suggests divergence of North American eastern and western gray foxes in the Irvingtonian mid-Pleistocene into separate sister taxa.[22] The gray fox's dwarf relative, the island fox, is likely descended from mainland gray foxes.[23] These foxes apparently were transported by humans to the islands and from island to island, and are descended from a minimum of 3–4 matrilineal founders.[22]

Distribution and habitat

A yawning gray fox, northern Florida

The species occurs throughout most rocky, wooded, brushy regions of the southern half of North America from southern Canada (Manitoba through southeastern Quebec)[24] to the northern part of South America (Venezuela and Colombia), excluding the mountains of northwestern United States.[25] It is the only canid whose natural range spans both North and South America.[26] In some areas, high population densities exist near brush-covered bluffs.[11]

Behavior

The gray fox is specifically adapted to climb trees. Its strong, hooked claws allow it to scramble up trees to escape many predators, such as the domestic dog or the coyote,[27] or to reach tree-bound or arboreal food sources. It can climb branchless, vertical trunks to heights of 18 meters and jump from branch to branch.[28] It descends primarily by jumping from branch to branch, or by descending slowly backwards like a domestic cat. The gray fox is primarily nocturnal or crepuscular and makes its den in hollow trees, stumps or appropriated burrows during the day. Such gray fox tree dens may be located 30 ft above the ground.[13](p122) For the most part, they rest on the ground rather than higher up in trees.

Prior to European colonization of North America, the red fox was found primarily in boreal forest and the gray fox in deciduous forest. With the increase in human populations in North America, their habitat selection has adapted: Gray foxes that live near human populations tend to choose areas near hardwood trees, locations used primarily by humans, or roads to utilize as their habitat.

The increase of coyote populations around North America has reduced certain fox populations, so gray foxes have to choose a habitat that will allow them to escape the coyote threat as much as possible, hence the choice of habitat nearer to areas where humans are active. The larger predators of the gray fox, like coyotes and bobcats, tend to avoid human-use areas and paved roads, making this habitat useful for the gray fox. They heavily utilize the edges of forests as a travel corridor, which is used for primary movement from place to place. Their choices do not change based on sex, the season, or the time of day. They also do the majority of their hunting in edges, and use them to escape from predators as well. Gray foxes are thus known as an “edge species”.[29]

Interspecies competition

A red fox (Vulpes vulpes) confronting a gray fox, San Joaquin Wildlife Refuge

Gray foxes often hunt for the same prey as bobcats and coyotes who occupy the same region. To avoid interspecific competition, the gray fox has developed certain behaviors and habits to increase their survival chances. In regions where gray foxes and coyotes hunt for the same food, the gray fox has been observed to give space to the coyote, staying within its own established range for hunting.[30][31] Gray foxes might also avoid their competitors by occupying different habitats than them. In California, gray foxes do this by living in chaparral where their competitors are fewer and the low shrubbery provides them a greater chance to escape from a dangerous encounter.[31] It also has been suggested that gray foxes could be more active at night than during the day to avoid their larger, diurnal competitors.[31]

Still, gray foxes frequently fall victim to bobcats and coyotes. When killed, the carcasses are often unconsumed, suggesting they are victims of intraguild predation.[30] These gray foxes are often killed on or near the boundary of their established range, when they begin to interfere with their competitors.[30] Gray foxes are known as mesopredators because they are mid-tier predators and their prey consists mostly of smaller mammals, while coyotes are known as de facto apex predators due to the removal of other apex predators like wolves in North America.[32][33] This explains the gray fox's tendency to change behavior in response to the coyote threat, as they are essentially lower on the food chain.

Reproduction

The gray fox is assumed to be monogamous, like other foxes. The breeding season of the gray fox varies geographically; in Michigan, the gray fox mates in early March, in Alabama, breeding peaks occur in February. The gestation period lasts approximately 53 days. Litter size ranges from 1–7, with a mean of 3.8 young per female.

Gray fox kits at Zion Canyon

The sexual maturity of females is around 10 months of age. Kits begin to hunt with their parents at the age of 3 months. By the time that they are 4 months old, the kits will have developed their permanent dentition and can now easily forage on their own. The family group remains together until the autumn, when the young males reach sexual maturity, then they disperse.[21] In a study of 9 juvenile gray foxes, only the males dispersed up to 84 km (52 mi). The juvenile females stayed within proximity of the den within 3 km (1.9 mi) and always returned.[34] On the other hand, adult gray foxes showed no signs of dispersion for either gender.[35] The gray fox will typically live between six and ten years.[36]

The annual reproductive cycle of males has been described through epididymal smears and become fertile earlier and remain fertile longer than the fertility of females.[21]

Logs, trees, rocks, burrows, or abandoned dwellings serve as suitable den sites. Dens are used at any time during the year but mostly during whelping season. Dens are built in brushy or wooded regions and are better concealed than the dens of the red fox.[11]

Diet

A gray fox at night
Adult male and female gray fox

The gray fox is an omnivorous, solitary hunter. It frequently preys on the eastern cottontail (Sylvilagus floridanus) in the eastern U.S., though it will readily catch voles, shrews, and birds. In California, the gray fox primarily eats rodents (such as deer mice, woodrats, and cotton rats),[37] followed by lagomorphs, e.g. jackrabbit, brush rabbit, etc.[27] When available, gray foxes may also feed on carrion.[37] In some parts of the Western United States (such as in the Zion National Park in Utah), the gray fox is primarily insectivorous and herbivorous.[13](p124) Fruit is an important component of the diet of the gray fox and they seek whatever fruits are readily available, generally eating more vegetable matter than does the red fox (Vulpes vulpes).[7] Generally, there is an increase in fruits and invertebrates (such as grasshoppers, beetles, butterflies, and moths)[37] within the gray fox's diet in the transition from winter to spring. As nuts, grains, and fruits become more numerous, they are cached by foxes. Typically, they attempt to cover the area with their scent either through their scent glands or urine. This marking serves the dual purpose of allowing them to find the food again later and preventing other animals from taking it.[38]

Ecosystem role

Since woodrats, cotton rats, and mice make up a large part of the gray fox's diet, they serve as important regulators of small rodent populations.

In addition to their beneficial predation on rodents, gray foxes are also less welcome hosts to some external and internal parasites, which include fleas, lice, nematodes, and tapeworms.[38] In the United States, the most common parasite of the gray fox is a flea (Pulex simulans); however, several new parasitic arthropods were found in populations in central Mexico, and a warming climate may encourage them to migrate north.[39]

Hunting

Gray foxes are hunted in the U.S. The intensity of the hunting has correlated with the value of their pelts. Between the 1970–1971 and 1975–1976 hunting seasons, the price of gray fox pelts greatly increased and the number of individuals hunted jumped over six-fold from 26,109 to 163,458.[21] It has been recently reported that over 500,000 gray foxes are killed every year for their fur.[40]

Subspecies

Gray fox skull

There are 16 subspecies recognized for the gray fox.[21]

  • Urocyon cinereoargenteus borealis (New England)
  • Urocyon cinereoargenteus californicus (southern California)
  • Urocyon cinereoargenteus cinereoargenteus (eastern United States)
  • Urocyon cinereoargenteus costaricensis (Costa Rica)
  • Urocyon cinereoargenteus floridanus (Gulf states)
  • Urocyon cinereoargenteus fraterculus (Yucatán)
  • Urocyon cinereoargenteus furvus (Panama)
  • Urocyon cinereoargenteus guatemalae (southernmost Mexico south to Nicaragua)
  • Urocyon cinereoargenteus madrensis (southern Sonora, south-west Chihuahua, and north-west Durango)
  • Urocyon cinereoargenteus nigrirostris (south-west Mexico)
  • Urocyon cinereoargenteus ocythous (Central Plains states)
  • Urocyon cinereoargenteus orinomus (southern Mexico, Isthmus of Tehuantepec)
  • Urocyon cinereoargenteus peninsularis (Baja California)
  • Urocyon cinereoargenteus scottii (south-western United States and northern Mexico)
  • Urocyon cinereoargenteus townsendi (northern California and Oregon)
  • Urocyon cinereoargenteus venezuelae (Colombia and Venezuela)

Parasites

Parasites of gray fox include trematode Metorchis conjunctus.[41] Other common parasites that were collected on gray foxes in Texas were a variety of tapeworms (Mesocestoides litteratus, Taenia pisiformis, Taenia serialis) and roundworms (Ancylostoma caninum, Ancylostoma braziliense, Haemonchus similis, Spirocerca lupi, Physaloptera rara, Eucoleus aerophilus). T. pisiformis was the most common parasite species and was associated with frequent impacts on health.[42]

See also

References

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Gray fox: Brief Summary

provided by wikipedia EN

The gray fox (Urocyon cinereoargenteus), or grey fox, is an omnivorous mammal of the family Canidae, widespread throughout North America and Central America. This species and its only congener, the diminutive island fox (Urocyon littoralis) of the California Channel Islands, are the only living members of the genus Urocyon, which is considered to be genetically basal to all other living canids. Its species name cinereoargenteus means "ashen silver".

It was once the most common fox in the eastern United States, and though still found there, human advancement and deforestation allowed the red fox to become the predominant fox-like canid. Despite this post-colonial competition, the gray fox has been able to thrive in urban and suburban environments, one of the best examples being southern Florida. The Pacific States and Great Lakes region still have the gray fox as their prevalent fox.

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