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Lycalopex griseusSouth American gray fox(Also: Argentine gray fox)

By Kenlyn Knop

Geographic Range

The Argentine gray fox is wide spread throughout Patagonia and western Argentina. It was introduced to Tierra del Fuego in 1951 to control the European rabbit. This area now has the highest population density. These foxes are also found on several small islands off the western coast of West Falkland, in Chile, southern Peru, and are believed to exist in central Peru. They live on both sides of the Andes Mountains (23° S to 55° S). Both hunting, legal and illegal, and the Lycalopex culpaeus may limit the gray fox’s distribution, even though their territories do not overlap. (Nowak, 1999; The World Conservation Union, Species Survival Commission, Canid Specialist Group, 1998)

Habitat

The Argentine gray fox likes to live in lowlands and foothills of coastal mountain ranges, plains, pampas, deserts, low open grasslands and forest edge habitats. They live on shrubby sandy soils. (Nowak, 1999; The World Conservation Union, Species Survival Commission, Canid Specialist Group, 1998)

Physical Description

The coat is brindled gray, the underparts paler grays. The head is a rust color flecked with white and a black spot on the chin. The Argentine gray fox has large ears and a long and bushy tail. The molars are well developed, and the carnassials are relatively short. This fox can grow up to 2 to 4 kg. Its shoulder height is 40 to 45 cm, decreasing as latitude increases from 33° S to 54° S. The head-body length is 42 to 68 cm, and the tail length is from 30 to 36 cm. (The World Conservation Union, Species Survival Commission, Canid Specialist Group, 1998; Yahnke, 1995)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    2 to 4 kg
    4.41 to 8.81 lb
  • Range length
    42 to 68 cm
    16.54 to 26.77 in

Development

See Reproduction.

Reproduction

Studies of L. griseus in Patagonia indicate that mating is monogamous, with a mated pair maintaining their territory throughout the year. Occasionally, a second female was present on the territory, and assisted in rearing the young, although she did not produce young herself. (Nowak, 1999)

The Argentine gray fox mates from August through September and the pups are born by October. The gestation period is 53 to 60 days and the litter size is 2 to 6 pups. Time of weaning is not known, but when the pups are 4 to 6 weeks, they start to leave the den with their mothers. By January, they go out by themselves to hunt for small mammals and arthropods. Age of sexual maturity is about 1 year. (Johnson, 1992; The World Conservation Union, Species Survival Commission, Canid Specialist Group, 1998)

  • Breeding interval
    Argentine gray foxes breed once yearly.
  • Breeding season
    Breeding occurs from August through October.
  • Range number of offspring
    2 to 6
  • Range gestation period
    53 (high) days
  • Average gestation period
    60 days
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

Both males and females are active in caring for the young. As in all mammals, the female nurses the young, although there are not good data on lactation in this species. In general, canid young are altricial. The male helps to maintain the territory where prey are obtained, and, as in other members of the genus Pseudalopex , may help to provide food for the growing family. Occasionally, an additional female is present on the territory, and she apparently also assists in rearing the young. (Nowak, 1999)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • post-independence association with parents
  • extended period of juvenile learning

Lifespan/Longevity

Data on lifespan for L. griseus are not available. However an individual from a congeneric species, Lycalopex gymnocercus, lived for 13 years and 8 months in capivity. (Nowak, 1999)

Behavior

Lycalopex griseus is nocturnal. One breeding pair has a year-round territory and seems to be the center of the social system. Some males do mate with other subordinate females who will then help to rear the young of the primary female. These foxes tend to be solitary in the winter. (Johnson, 1992)

Communication and Perception

Food Habits

Argentine gray foxes are omnivorous and diet changes seasonally. European rabbits and birds are preferred, as well as fruits, seeds, berries, small mammals, insects, scorpions, lizards, frogs, and bird eggs. Sheep predation is minimal and usually only eaten as carrion. In the winter months, carrion seems to become the most important food source, along with rodents and armadillos. (Johnson,1992; Puig, 1997; Jaksic, 1983) In areas of human habitation, L. griseus may take domestic poultry (Nowak, 1999). (Jaksic and Yanez, 1983; Johnson, 1992; Nowak, 1999)

  • Animal Foods
  • birds
  • mammals
  • amphibians
  • reptiles
  • eggs
  • carrion
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • seeds, grains, and nuts
  • fruit

Predation

Predation on this species has not been described in the literature.

Ecosystem Roles

The Argentine gray fox helps to control small mammal and bird populations. It also disperses seeds by eating the fruit then defecating the seeds.

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

There is an important pelt trade in South America. According to CITES, from 1980 to 1983, 381,000 fox skins were exported, 98% of which were purported to have originated in Argentina. Over 7,000 skins were recorded as being exported from Chile, despite the species being protected in that country. Most exports were made to West Germany (72%), Switzerland (7.2%), and Italy (4.4%).

As noted previously, these carnivorous foxes eat both European rabbits and small rodents. They are therefore probably important in limiting pest populations. (The World Conservation Union, Species Survival Commission, Canid Specialist Group, 1998)

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

Economic Importance for Humans: Negative

Local people believe that these foxes prey upon sheep and domestic fowl, although scat analysis indicates that such predation is probably not common. (Nowak, 1999)

Conservation Status

The Argentine gray fox is protected by law in Chile but enforcementof this law is lax. No hunting or skin trade has been permitted since 1929 in some areas, although fox skins are still exported through Chile via Argentina. The Argentine Wildlife Board (Direccion Nacional de Fauna Silvestre) has classified the species as endangered. Hunting is banned year-round in some areas.

In Rio Nego, Patagonia, population levels have been stable since 1983, in spite of heavy harvesting for furs. Deep snowfall can depress population levels, but recovery is usually speedy. (Nowak, 1995; The World Conservation Union, Species Survival Commission, Canid Specialist Group, 1998)

Other Comments

Darwin’s foxes (Pseudalopex fulvipes) were previously considered a subspecies of Argentine gray foxes, as Pseudalopex griseus fulvipes. They are now considered a separate species, reasons include: their shorter legs and a darker pelage and the fact that they don't interbreed where the two are sympatric. Tests of mitochondrial DNA have concluded that Darwin’s foxes and Argentine gray foxes are distinct species (Yahnke et al., 1996). The cranium size has a shorter, broader facial region, a smaller auditory bullae, heavier dentition, occlusion of the premolars nearly complete, mandible angle deeper and heavier; all of which brings it closer to the Sechurae fox, rather than the Chilla fox, supporting a sister relationships between Argentine gray foxes and Darwin’s foxes (Yahnke, 1995).

Lycalopex griseus seems to have split from a more wolf-like lineage than did Vulpes about 7 million years ago. It evolved into its current form about 1 or 2 million years ago (Johnson, 1992).

Argentine gray foxes were previously recognized as Pseudalopex griseus. (Johnson, 1992; Yahnke, 1995)

Contributors

Kenlyn Knop (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor), University of Wisconsin-Stevens Point.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carrion

flesh of dead animals.

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

cooperative breeder

helpers provide assistance in raising young that are not their own

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

omnivore

an animal that mainly eats all kinds of things, including plants and animals

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Jaksic, F., J. Yanez. 1983. Rabbit and Fox Introductions in Tierra del Fuego: History and Assessment of the Attempts at Biological Control of the Rabbit Infestation. Biological Conservation, 26: 367-374.

Johnson, W. 1992. Patagonia's Little Foxes. Natural History, 101: 26-28.

Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition. Baltimore nd london: The Johns Hopkins University Press.

Nowak, R. 1995. "Walker's Mammals of the World, Online. South American Foxes" (On-line). Accessed November 28, 2001 at http://www.press.jhu.edu/books/walker/carnivora.canidae.pseudalopex.html.

Puig, S. 1997. Mammalia, 61: 617-621.

The World Conservation Union, Species Survival Commission, Canid Specialist Group, 1998. "Gray Zorro" (On-line). Accessed November 28, 2001 at http://www.canids.org/SPPACCTS/dgriseus.htm.

Yahnke, C. 1995. Metachromism and the Insight of Wilfred Osgood: Evidence of Common Ancestory for Darwin’s Fox and the Sechura Fox. Revista Chilena de Historia Natural, 68: 459-467.

Yahnke, C., W. Johnson, E. Geffen, D. Smith, F. Hertel. 1996. Darwin’s Fox: A distinct endangered species in a vanishing habitat. Conservation Biology, 10(2): 366-375.

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