The maned wolf has often been described as "a red fox on stilts" owing to its similar coloration and overall appearance, though it is much larger than a red fox and belongs to a different genus. The adult animal stands 67 to 107 cm (26 to 42 in) tall at the shoulder, averages 125 cm (49 in) in head-and-body length and weighs 20 to 34.09 kg (44 to 75.2 lb). The maned wolf is the tallest of the wild canids. The long legs are probably an adaptation to the tall grasslands of its native habitat.
Although the maned wolf displays many fox-like characteristics, it is not closely related to foxes and lacks the elliptical pupils found in foxes. The maned wolf's evolutionary relationship to the other members of the canid family makes it a unique animal. Electrophoretic studies did not link Chrysocyon with any of the other canids studied. One conclusion of this study is that the maned wolf is the only survivor of the late Pleistocene extinction of the large South American canids. Fossils of the maned wolf from the Holocene and the late Pleistocene have been excavated from the Brazilian Highlands.
A study, published in 2003, on the brain anatomy of several canids, placed the maned wolf together with the Falkland Islands wolf, and with pseudo-foxes of the genus Pseudalopex. One study based on DNA evidence, published in 2009, showed that the extinct Falkland Islands wolf was the most closely related species to the maned wolf in historical times, and shared a common ancestor with it about 6 million years ago.
Its closest living relative is the bush dog (genus Speothos), with a more distant relationship to other South American canines (the short-eared dog, the crab-eating fox and the 'false foxes' or Pseudalopex).
The maned wolf is not closely related to any other living canid. It is not a fox, wolf, coyote, dog, or jackal, but a distinct canid, although previously it had been placed in Canis and Vulpes genera based on morphological similarities.
Fur of the maned wolf may be reddish brown to golden orange on the sides with long, black legs and a distinctive black mane. The coat is further marked with a whitish tuft at the tip of the tail and a white "bib" beneath the throat. The mane is erectile, and is typically used to enlarge the wolf's profile when threatened or when displaying aggression.
Unlike other large canids (such as the gray wolf, the African hunting dog, or the dhole) the maned wolf does not form packs. It hunts alone, usually between sundown and midnight. It kills its prey by biting on the neck or back, and shaking it violently if necessary. Monogamous pairs may defend a shared territory of about 30 km2 (12 sq mi), though the wolves themselves may seldom meet, outside of mating. The territory is crisscrossed by paths that the wolves create as they patrol at night. Several adults may congregate in the presence of a plentiful food source; a fire-cleared patch of grassland, for example, which would leave small vertebrate prey exposed to foraging.
Both male and female maned wolves use their urine to communicate, e.g. to mark their hunting paths, or the places where they have buried hunted prey. The urine has a very distinctive smell, which some people liken to hops or cannabis. The responsible substance is very likely a pyrazine, which occurs in both plants. (At the Rotterdam Zoo, this smell once set the police on a hunt for cannabis smokers.)
The mating season ranges from November to April. Gestation lasts 60 to 65 days, and a litter may have from 2 to 6 black-furred pups, each weighing about 450 g (16 oz). These pups are fully grown in about one year. During that year, the pups are known to rely on their parents for food.
The maned wolf specializes in small and medium-sized prey, including small mammals (typically rodents and hares), birds, and even fish. A large fraction of its diet (over 50%, according to some studies) is vegetable matter, including sugarcane, tubers, and fruit (especially the wolf apple (A tomato-like food)). Captive maned wolves were traditionally fed meat-heavy diets and developed bladder stones. Zoo diets now feature fruits and vegetables, as well as meat and dog chow.
Maned wolves rotate their large ears to listen for prey animals in the grass. They tap the ground with a front foot to flush out the prey and pounce to catch it.