Interim profile, incomplete information
Taxonomic name: Lycalopex griseus (Gray, 1837)
Synonyms: Dusicyon griseus , Lycalopex griseus (Gray, 1837), Pseudalopex griseus (Gray, 1837)
Common names: Argentine gray fox, Argentine grey fox, Argentinean grey fox, atoj (Quechua-Argentina/Chile), chico gray fox, chico grey fox, chilla (Spanish), gray zorro, grey zorro, nguru (Araucano), nuru (Araucano), n'uru (Araucano-Argentina/Chile), Patagonian fox, Patagonischen fuchs (German), renard gris (French), South American gray fox, South American grey fox, yeshgai (Peulche-Argentina/Chile), zooro gris Patagonico (Spanish), zorro chico (Spanish), zorro chilla (Spanish), zorro de la pampa (Spanish-Chile), zorro gris (Spanish-Chile), zorro gris chico (Spanish-Argentina)
Organism type: mammal
In its native range the chilla, Lycalopex griseus is scare and is rarely seen in the wild because of hunting. Native to mainland South America it was introduced into the Falkland where it has proved to have a negative impact on native birds.
A fox-like canid with a small grey body, measurements as follows: Head-body length: 446 to 670 millimeters; Tail: 202 to 427 millimeters; Weight: 2.5 to 5.45 kilograms. Head rufescent, flecked with white, large ears, chin with well marked black spot. Coat brindled grey, made up of agouti guard hairs with pale underfur. Thighs crossed by a black patch. Legs and feet pale tawny. Underparts pale grey. Tail long and bushy, with dorsal line and tip black. Tail’s underside presents a mixed pale tawny and black pattern (Osgood 1943; Long 2003; Clutton-Brock et al. 1976, in del Solar & Rau 2004).
Lycalopex culpaeus, Lycalopex fulvipes, Lycalopex gymnocercus
desert, range/grasslands, riparian zones, scrub/shrublands, tundra
The chilla is mainly crepuscular (active at dawn and dusk) and nocturnal but it is occasionally diurnal; it makes its den among rocks, tree bases, low shrubs or in the burrows of other animals. Habitats include: plains/low open grasslands/pampas, scrublands/shrublands, deserts, forest edges, low mountains/mountain foothills (Long 2003; Ginsberg & Macdonald 1990). In its native range the chilla dwells mainly on the slopes of Cordillera de los Andes (Jaksic et al. 1983).
In Argentina it occurs in the western and southern arid and semi-arid regions of the country. In Argentina and Chile the chilla occurs in steppes, pampas grasslands and scrublands (Olrog and Lucero 1981, in Jiménez et al 2008). The chilla generally inhabits plains and low mountains but has been reported to occur as high as 3500 to 4000 meters (Marquet et al. 1993, Jayat et al. 1999, in Jiménez et al 2008). Although the chilla occurs in a variety of habitats it is more common in open shrublands rather than in dense vegetation or ravines. It reportedly visits some ravines in search of fruit (Jaksic et al. 1980, Jiménez et al. 1996, in Jiménez et al 2008). In Chilean Patagonia the typical habitats of the chilla are steppes and shrublands composed of coirón grass (Festuca spp. and Stipa spp.) or Antarctic beech Nothofagus antarctica. Habitat disturbance caused by the slashing and burning of native forests to clear land for sheep farming seems to have been advantageous for the chilla. In the north-eastern Mendoza desert (Argentina) the chilla seems to prefer low shrubby sand dunes rather than higher areas (Jiménez et al 2008).
Chillas are tolerant of climatic regimes from remarkably hot and dry areas such as the Atacama coastal desert in northern Chile (less than 0 mm average annual rainfall, 22 degrees C mean annual temperature), to the humid regions of the temperate Valdivian forest (2000 mm average annual rainfall, 12 degrees C mean annual temperature) and the cold Tierra del Fuego (ca. 400 mm average annual rainfall, 7 degrees C mean annual temperature (Jiménez et al 2008). This high tolerance for different temperature variables may have implications for the potential future range expansion of the chilla and its subsequent impact on prey species as climate changes occur (due to human activities which involve the burning of fossil fuels).
The chilla is reported as a farmer's pest. It target lambs on farmland across its native distribution and in the Falkland Islands (Bellati and von Thungen 1990, Miller 1998, in Otley et al. 2008). The chilla is considered a voracious predator of livestock, poultry and game in some areas (eg: parts of Mendoza, Argentina, Chile) and goat breeders have claimed losses to the chilla. A survey carried out in Chile found that each family lost on average of 34.5% of their hens, although as this figure is based on reports by farmers it may be overestimated. As such most research participants (67.4%) had negative attitudes towards chilla (Silva-Rodriguez et al., 2009b). It is uncertain whether the remains of domestic animals present in chilla faeces and stomachs are from live animals or just carrion. It is unlikely whether the chilla could tackle anything larger than a new-born lamb; of which there is no doubt that it takes (del Solar & Rau 2004). Scat analysis confirmed that they do take chickens (Silva-Rodriguez et al., 2009b).
Pseudalopex griseus preys on the adults, fledglings and eggs of steamer ducks, crested ducks and kelp geese on Beaver Island, Falklands where fox control has resulted in an increase in the abundance of these species (Poncet 1998, in Otley et al. 2008).
The commercial use of the chilla in South America is considerable; most fox skins originate from Argentina or are shipped via Argentina. 382 000 skins were shipped between 1980 and 1983 (an average of about 130 000 skins annually). Most exports went to West Germany, Switzerland and Italy (IUCN 1988, in Ginsberg & Macdonald 1990).
Lycalopex griseus is listed on the IUCN red list with the lowest risk status ‘least concern’. In 1990 and 1994 it was listed as vulnerable.
There has been a general disagreement as to generic classification of the South American canids, with most of the disagreement centered on the species australis, culpaeus, griseus, gymnocercus, microtis, sechurae, thous and vetulus (ITIS Dusicyon C. E. H. Smith, 1839). The accepted name of the chilla or Patagonian fox is Lycalopex griseus; it was previously Pseudalopex griseus and previous to that Dusicyon griseus (Otley et al. 2008). Scientific names used in this species profile are faithful to the information given in the sources.
Subspecies of P. griseus (del Solar & Rau 2004): P. g. domeykonus: Chile to southern Peru; P. g. gracilis: Western Argentina; P. g. maullinicus: Southern temperate forests of Argentina and Chile; P. g. griseus: Patagonia.
Native range: Chilla are reported to occur in South America from southern Ecuador to southern Chile and Argentina including Tierra del Fuego (Long 2003).
Known introduced range: Jiménez et al (2008) report the species as native to Argentina and Chile, introduced to the Falkland Islands (Malvinas) and presence uncertain in Ecuador and Peru.
Introduction pathways to new locations
Biological control: Sheep ranchers attempted to control rabbit populations on their farms by introducing foxes Dusicyon griseus from the mainland to Tierra del Fuego (Goodall 1979, in Jaksic 1983).
Local dispersal methods
Natural dispersal (local): The grey fox spread over Tierra del Fuego Island across relatively flat and open expanses and crossed several major rivers in the process (Jaksic et al. 2002).
There are few if any successful fox eradication programmes anywhere in the world, except on the Aleutian Islands, where over 40 islands have been cleared of Arctic foxes (Otley et al. 2008).
Beaver Island Farm gained funds from the Overseas Territories Environment Programme (OTEP), Falkland Islands Government, Falklands Conservation and Antarctic Research Trust to attempt the eradication of chilla from Tea Island (300 ha) during 2008 (in conjunction with the eradication of black rats). An eradication plan is currently being drafted by fox eradication specialists in Alaska, and it is likely the plan will have to be a combination of poisoning, chemical lures, trapping, tracking with dogs and shooting (Otley et al. 2008).
In their native range in South America chillas are hunted on the belief that they prey on livestock and poultry. Shooting, poison, dogs, snares and foothold traps are all used on the fox. Hunting occurs despite legal protection. Chillas are also hunted for their pelts (del Solar & Rau 2004).
Chilla is an opportunistic omnivore, feeding on rodents, rabbits, berries, reptiles, birds, eggs, arthropods, sheep carrion and plant material (grass) (Long 2003; Zapata et al. 2005 and references therein, in Otley et al. 2008). For greater detail please see del Solar & Rau (2004).
On Weddell Island (Falklands) birds and mammals represent about 80% of the diet of the fox; all shot foxes during the early lambing season were found to have eaten lambs (Miller 1998, in Otley et al. 2008). Insects, mussels, plants and berries and rat were also found in examined fox faeces and digestive tracts (Otley et al. 2008). Berries are consumed particularly in autumn and include those of the peumo plant Cryptocarya alba and those of Lithraea caustica. In central and northern Chile rodents comprise the greatest proportion of the foxes’ prey making up to 98% of the prey items in faeces examined; birds comprise only about 3%. In Tierra del Fuego small animals and the berries of the Magellan barberry Berberis buxifolia were the main dietry components of the chilla (Jaksic et al. 1983, Yanez & Jaksic 1978). The diet of D. griseus in Tierra del Fuego has been found to be more diversified than that of the native fox on the island D. culpaeus and birds accounted for an important fraction of its prey (Jaksic 1983). In a study on Dusicyon foxes on Tierra del Fuego were found to have consumed the following (Jaksic 1983): Artiodactyla carrion (D. griseus is apparently more of a scavenger than D. culpaeus); European cattle Bos taurus; domestic sheep Ovis aries; Lagomorpha (rabbits are a small fraction of the diet of D. griseus compared with D. culpaeus); European rabbit Oryctolagus cuniculus; Rodentia yellow-nosed grass mouse Akodon xanthorhinus; the 'Vulnerable (VU)' Magellanic tuco-tuco (see Ctenomys magellanicus in IUCN Red List of Threatened Species); coney rat Reithrodon physodes; birds [Anseriformes] upland goose Chloephaga picta; crested duck Lophonetta specularioides; [Charadriiformes] kelp gull Larus dominicanus; [Falconiformes] chimango caracara Mivago chimango; [Passeriformes] black-chinned siskin Carduelis barbata; dark-faced ground-tyrant Muscisaxicola macloviana; Falkland thrush Turdus falklandii; reptiles; Squamata: Magellan's tree iguana; Insects (mainly lepidopteran larvae and coleopteran adults; a few arachnids, tunicates, amphipods, and polychaetes) were also detected. D. griseus seems to prey on invertebrates more frequently than its congener D. culpaeus. Plant material detected included mainly Gramineae and the leaves, stems, and bark of dicots.
Breeding: August to September; Gestation: 53 to 58 days; Litter Size: two to five but may be variable. Lactation: unknown; Age to Sexual Maturity: one year but uncertain (Cattanj Pers. Comm., in Ginsberg & Macdonald 1990)
Longevity: probably only several years in the wild (but uncertain) and 13 years in captivity (Ginsberg & Macdonald 1990; Long 2003).
Compiled by: IUCN SSC Invasive Species Specialist Group (ISSG) with support from the EU-funded South Atlantic Invasive Species project, coordinated by the Royal Society for the Protection of Birds (RSPB)
Last Modified: Tuesday, 10 August 2010