Thecrab-eating fox (Cerdocyon thous), also known as theforest dog,wood fox,bushfox (not to be confused with thebush dog) ormaikong, is anextant species of medium-sizedcanid endemic to the central part ofSouth America since at least thePleistocene epoch.[1][2][4] LikeSouth American foxes, which are in thegenusLycalopex, it is not closely related to true foxes.Cerdocyon comes from theGreek wordskerdo (meaning fox) andkyon (dog) referring to the dog- and fox-like characteristics of this animal.[5]
The crab-eating fox was originally described asCanis thous by Linnaeus (1766), and first placed in its current genusCerdocyon by Hamilton-Smith in 1839.[4]
Cerdocyonina is atribe which appeared around 6.0 million years ago (Mya) inNorth America asFerrucyon avius becoming extinct by around 1.4–1.3 Mya. living about4.7 million years. This genus has persisted in South America from an undetermined time, possibly around 3.1 Mya, and continues to the present in the same or a similar form to the crab-eating fox.[6]
As one of the species of the tribeCanini, it is related to the genusCanis. The crab-eating fox's nearest living relative, as theorized at present, is theshort-eared dog. This relationship, however, has yet to be supported by mitochondrial investigations. Two subgenera (Atelocynus andSpeothos) were long ago included inCerdocyon.
Cerdocyon thous,C. avius and other species of the genusCerdocyon underwent radiational evolution on the South American continent.[7] All close relatives of the crab-eating fox (Cerdocyon thous) are extinct. It is the only living representative at present of the genusCerdocyon.
The crab-eating fox is predominantly greyish-brown, with areas of red on the face and legs, and black-tipped ears and tail. It has short, strong legs and its tail is long and bushy. The head and body length averages 64.3 centimetres (25.3 in), and the average tail length is 28.5 centimetres (11.2 in).[8] It can weigh between 10 and 17 pounds (4.5 and 7.7 kg).[9][10]
The coat is short and thick. Coloration varies from grey to brown, to yellowish, to pale, to dark grey. There is a black streak along the back legs, with a black stripe along the spine. On muzzle, ears and paws there is more-reddish fur. The tail, legs and ear tips are black. The ears are wide and round. The torso is somewhat narrow; legs are short but strong. The dense hairy tail stays upright when they are excited. There is significant variation in color between population, from very dark to light grey-yellow.[4]
Genetically, there are 74diploid chromosomes (36 pairs).
Its habitat also includes wooded riverbanks such asriparian forest. In the rainy season, their range moves uphill, whilst in drier times they move to lower ground.[13] Their habitat covers all environments exceptrainforests, high mountains, and open grassy savannas. In some regions of their range, they are threatened with extirpation.
The crab-eating fox createsmonogamic teams for hunting; groups of several monogamic pairs may form during the reproductive season. Population density estimates vary between one individual per 4 km2 in Venezuela to 0.0003 individuals/km2 in Argentinian wetlands.[8][14][15]Territorialism was noticed during the dry season; during rainy seasons, when there is more food, they pay less attention to territory.[13] Hideouts anddens often are found in bushes and in thick grass, and there are typically multiple entrance holes per den. Despite being capable of tunneling, they prefer to take over other animals' burrows. Several characteristic sounds are made by the crab-eating fox such as barking, whirring andhowling, which occur often when pairs lose contact with one another.
The crab-eating fox is nocturnal, with peaks of activity in the middle of the night and the early morning.[16]
The foxes reach sexual maturity within 9–10 months. Adult females give birth to one or two litters per year, depending on the climate and the availability of food.[15] The reproductive period most often begins in November or December, and again in July. The birth of offspring follows after an approximately 56-day gestation,[17] typically in January, February or sometimes March,[13] then again from September to October. If giving birth to one litter, they typically give birth in the early spring. Thebreeding pair is monogamous and raises the pups together, which are weaned at around three months old and become independent of their parents around 5–8 months old.[15]
The crab-eating fox searches for crabs on muddyfloodplains during the wet season, giving this animal its common name. It is an opportunist and an omnivore, preferring insects or meat from rodents and birds when available. Other foods readily consumed includeother crustaceans, tortoises, turtle eggs,bird eggs, insects, lizards, fruit, andcarrion. Their diet is varied and has been found to differ by different researchers, suggesting opportunistic feeding and geographical variation. During thewet season, the diet contains more crustaceans, while during thedry season it contains more insects.[8] The crab-eating fox contributes to the control ofrodents andharmful insects.
The Convention on International Trade inEndangered Species of Wild Fauna and Flora (CITES) lists the fox as not threatened by extinction.[18] TheIUCN lists the crab-eating fox as being of "Least Concern".[2] There are no precise estimates of the population size, but it is common within its range and the population is stable.[4]
It is considered a threat to livestock by farmers, which leads to illegal hunting in some countries. The primary threat to the fox is disease from unvaccinated dogs.[14]
^Yahnke CJ, Johnson WE, Geffen E, Smith D, Hertel F, Roy MS, Bonacic CF, Fuller TK, Van Valkenburgh V, Wayne RK (1996) Darwin's fox: a distinct endangered species in a vanishing habitat. Conserv Biol 10:366–375
^J.F. Eisenberg, K.H. RedfordMammals of the Neotropics – The Central Neotropics, vol. 3, University of Chicago Press, Chicago (1999)
^Tejera-N, VH; Araúz-G., V. León, A. R. Rodríguez, P. González, S. Bermúdez & R. Moreno. 1999. Primer registro del zorro cangrejero Cerdocyon thous (Carnivora: Canidae), para Panamá. Scientia 14: 103–107
^abcNowak, Ronald M. (2005).Walker's Carnivores of the World. Baltimore: Johns Hopkins Press.ISBN0-8018-8032-7
^abcFaria-Corrêa, Mariana; Balbueno, Rodrigo A.; Vieira, Emerson M.; de Freitas, Thales R. O. (2009-05-01). "Activity, habitat use, density, and reproductive biology of the crab-eating fox (Cerdocyon thous) and comparison with the pampas fox (Lycalopex gymnocercus) in a Restinga area in the southern Brazilian Atlantic Forest".Mammalian Biology.74 (3):220–229.Bibcode:2009MamBi..74..220F.doi:10.1016/j.mambio.2008.12.005.ISSN1618-1476.
^Hutton, Jon, and Barnabas Dickson, eds. Endangered species, threatened convention: the past, present and future of CITES, the Convention on International Trade in Endangered Species of Wild Fauna and Flora. London: Earthscan, 2000.
^BISBAL, Francisco J. "A taxonomic study of the crab-eating fox, Cerdocyon thous, in Venezuela." Mammalia 52.2 (1988): 181–186.
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