The Crab-eating fox tends to have a similar size and shape to most foxes. It is mainly grayish-brown, with red areas on the legs and face, and on its long, bushy, black-tipped tail and ears. Its legs are short and strong and its coat is thick and short. Coloration varies from brown to pale or dark gray, to yellowish. Along the back legs there is a black streak, with a black stripe on the spine. On the muzzle, ears and paws the fur is more reddish. The ear tips, tail and legs are black and the ears are round and wide. The torso is rather narrow.
The Crab-eating fox lives in central South America. It ranges from Colombia and Venezuela as far as Uruguay, Paraguay, and Northern Argentina. Its habitat mostly includes savannahs and woodlands; however, it is known to live in a range of other areas including edge and forested areas. It may prefer higher areas during the rainy season, moving to lowlands in the dry season.
The Crab-eating fox is mainly nocturnal and is also active during dusk, spending the day in a den dug by other animals. These foxes travel together in pairs but hunt as individuals. Their territory ranges from 0.6 to 0.9 km2. In the dry season, these foxes have a tendency towards being more territorial than in the wet season, though overlap of territories often occurs. Hideouts and dens are often in thick grass and bushes, and each den usually has many entrance holes. Despite being capable diggers, the foxes prefer to take over the burrows of other animals. Hunting methods differ according to the type of prey. They make several characteristic sounds, including barking, howling and whining, when pairs of foxes lose contact.
Crab-eating foxes are monogamous. They often breed two times a year, 7 to 8 months apart, sometimes with a peak in births in January, February or sometimes March, and again in September to October. November or December is when the reproductive period usually begins, and again in July. Gestation lasts for 52 - 59 days, females giving birth to 2 - 6 cubs. The fox cubs are born with their eyes and ears shut, and without teeth. Their eyes open at 14 days. At 30 days they can start digesting solid food and at 3 months they are weaned. Sexual maturity is reached at 9 months.
The main threat to these animals is from pathogenic infection from dogs, as foxes forage in human refuse dumps alongside unvaccinated domestic dogs at park boundaries in Brazil’s Serra da Canastra National Park. This habitat of the crab-eating fox is gradually shrinking as a result of human activity, including agriculture, as well as the encroachment of feral dogs on its territory.
The IUCN Red List and other sources don’t provide the number of the Crab-eating fox total population size. Curently this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today remain stable.
Crab-eating foxes play an important role as predators in the ecosystems they inhabit by controlling populations of small mammals, insects, fish, and crabs.