The crab-eating fox (Cerdocyon thous), also known as the forest dog, wood fox, bushfox (not to be confused with the bush dog) or maikong, is an extant species of medium-sized canid endemic to the central part of South America since at least the Pleistocene epoch.
Taxonomy and evolution
The crab-eating fox was originally described as Canis thous by Linnaeus (1766), and first placed in its current genus Cerdocyon by Hamilton-Smith in 1839.
Cerdocyonina is a tribe which appeared around 6.0 million years ago (Mya) in North America as Ferrucyon avius becoming extinct by around 1.4–1.3 Mya. living about . 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.
As one of the species of the tribe Canini, it is related to the genus Canis. The crab-eating fox's nearest living relative, as theorized at present, is the short-eared dog. This relationship, however, has yet to be supported by mitochondrial investigations. Two subgenera (Atelocynus and Speothos) were long ago included in Cerdocyon.
Cerdocyon thous, C. avius and other species of the genus Cerdocyon underwent radiational evolution on the South American continent. All close relatives of the crab-eating fox (Cerdocyon thous) are extinct. It is the only living representative at present of the genus Cerdocyon.
Description
thumb|C. thous
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 , and the average tail length is . It can weigh between .
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. The crab-eating fox has also been sighted in Panama since the 1990s.
Its habitat also includes wooded riverbanks such as riparian forest. In the rainy season, their range moves uphill, whilst in drier times they move to lower ground. Territorialism was noticed during the dry season; during rainy seasons, when there is more food, they pay less attention to territory. Hideouts and dens 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 and howling, 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.
Reproduction
thumb|A juvenile crab-eating fox in captivity
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. typically in January, February or sometimes March, The IUCN lists the crab-eating fox as being of "Least Concern".
- C. t. thous, Venezuela, Guyana, Suriname, French Guiana North Brazil.
- C. t. azarae, North Brazil.
- C. t. entrerianus, Brazil, Bolivia, Uruguay, Paraguay and Argentina.
- C. t. aquilus, north Venezuela and Colombia.
- C. t. germanus, Bogotá region (Colombia).