Chrysocyon brachyurus - Maned Wolf

Skull Pictures:

Dorsal    Ventral

Dentary (lateral view)    Dentary (dorsal view)

Photos by Christopher Yahnke, collection of the Field Museum of Natural History

Physical Description:

The maned wolf (Chrysocyon brachyurus) is the fourth-largest member of Canidae, and the largest of the South American canids (Bestelmeyer and Westbrook 1998).  The average adult weight is 23 kg and a typical animal is 90 cm tall at the shoulder. Total body length averages approximately 147 cm, where 45 cm is tail (Dietz 1985).

Maned wolves are a rich reddish brown in color.  They have a long neck with a distinctive dorsal erect mane and this feature is where they get their name. Their chestnut coloration blends to black on the muzzle, legs and feet (Bueler 1973).  The posterior half of the shaggy tail is white, as are the insides of the ears and the underside of the chin (Dietz 1985).

The maned wolf has a small, fox-like head with a long, slender muzzle.  They have extremely long vibrissae (Dietz 1985).  Their large ears stand erect and are used for visual signaling to conspecifics (Bueler 1973).  The wolves have extremely long, thin legs, which are thought to assist them in seeking out prey in the tall grasses of their habitat.  Their hind legs are significantly longer than their front legs, which gives them an awkward, pacing gait (Dietz 1985).  Their tracks are distinctive, as the pads of the third and fourth toes are merged on both the front and hind feet (Bueler 1973).

Adult maned wolves have 42 teeth, which is typical of canids (Kleiman 1972).  They do not pursue much large prey, and as a result they exhibit reduced carnassials, weak upper incisors and long, slender canines (Dietz 1985).

Distribution:

Maned wolves live in the grasslands and scrub forests of central South America (Dietz 1985).  Their range extends from the edge of the Amazon basin forest in Brazil, south through Paraguay and northern Argentina to the edge of the treed savanna, and as far west as the eastern edge of Bolivia (Bueler 1973).  They have been extirpated from Uruguay and from southern Brazil (Dietz 1985). Paraguayan maned wolves are principally found in the Chaco region (Dietz 1985).

Ontogeny and Reproduction:

Female maned wolves are monestrous.  The induction of estrus appears to be triggered by photoperiod, and occurs between August and October in South America (Dietz 1985).  Estrus lasts approximately five days.  The copulation includes a typical canine "tie".  Gestation is approximately 65 days, after which litters of 2-5 pups are born into a nest hidden in thick vegetation (Bueler 1973).  Observations of captive wolves indicate that the female grows very long abdominal hair prior to giving birth, and shows no other external signs of pregnancy (Uka 1986).

It is unknown the extent, if at all, that wild male wolves assist in the rearing of pups.  However, in captivity they have been observed assisting with parturition, grooming pups, regurgitating to pups and to the female, and guarding and playing with the pups (Bestelmeyer 1999).

Pups are approximately 340-430 g at birth (Dietz 1985).  They are born with a fuzzy covering of dark brownish-grey fur (Bueler 1973).  Pups develop rapidly, with their eyes and ears opening by day 9, their pinnae standing erect by week 4, and their fur changing from dark grey to red by their 10th week.  Their legs do not reach adult proportions until they are one year old, at which point they are also sexually mature (Dietz 1985).  Little is known about life expectancy of maned wolves in the wild, but they typically live 12-15 years in captivity (Dietz 1984).

Ecology and Behavior:

Maned wolves are nocturnal hunters with crepuscular activity peaks (Dietz 1985).  Dietz (1984) found that they spend 33% of their time in grassland areas, 43% in wooded savannas, and 24% in forested habitats.  They are also found in swampy areas (Kleiman 1972).

Early field studies identified maned wolves as solitary, timid animals (Bueler 1973).  Monogamous male and female pairs will defend a territory of approximately 27 sq km, but this pair bond has been thought to occur only during the mating period (Dietz 1985).  More recent observations have recorded more extensive male and female interactions in the wild, including grooming, playing and possibly hunting together, as well as calling the other member of the pair after a successful hunt (Bestelmeyer and Westbrook 1998).

Regardless of the duration of the male-female pair bond, maned wolves are one of the least-social of all canids.  They rely on signals that carry well over long distances to maintain the spatial separation of individuals, such as the bark, "sign-post" type urination and defecation areas, and a visually conspicuous threat display (Kleiman 1972).  In addition to the bark, which is actually a high-amplitude vocalization repeated at very brief intervals, maned wolves are also known to howl, snarl, whine and growl (Kleiman 1972, Bueler 1973, Dietz 1984).

Maned wolves are highly omnivorous and opportunistic.  They commonly eat rodents and other small mammals, reptiles, ground birds and their eggs, snails, slugs, various insects, frogs, and various fruits (Aragona and Setz 2001, Bueler 1973).  The lobeira (Solanum lycocarpum) is the most important fruit in the wolves' diet, followed by bananas, guavas and sugar cane (Bueler 1973, Juarez and Marinho-Filho 2002).  Maned wolves are often accused of predation on domestic fowl (Dietz 1984).  Recently, they have been observed scavenging trash in parks (Aragona and Setz 2001).

Although they have been thought to be restricted to small prey items due to their rather weak teeth and jaws, Bestelmeyer and Westbrook (1998) observed two single wolves chasing Pampas deer in only 57.5 hours of observation.  One of the attempts was successful, and in both cases the long legs of the wolves helped them to quickly close the distance between themselves and the fleeing deer.

Wolves are known to travel long distances in search of food (Bueler 1973).  They have been observed capturing prey with two primary techniques, a stiff-legged pounce, similar to that of a fox, and a bite to the head or neck followed by a rapid lateral head shake (Dietz 1984, Kleiman 1972).  They use their teeth, rather than their paws, to dig out rodents (Bueler 1973).  Prey items are often cached for later consumption, which is done by digging a hole for the food and then covering the item with dirt and vegetation (Kleiman 1972).

Remarks:

The Paraguayan name for the maned wolf is "aguará guazú", which translates to "large fox".  It is commonly called "guará" through most of its range (Dietz 1984).  Other names include "lobo crinado", red wolf, stilt-legged fox and giant fox (Bueler 1973).  The maned wolf is an important part of Brazilian folk culture, as it is believed to have inexplicable supernatural powers, and is a key ingredient in many folk medicines and remedies (Dietz 1984).

Maned wolves are often killed for sport by running them with dogs or lassoing them from horseback.  They are also regularly dispatched for eating domestic fowl (Bueler 1973).  Additionally, they suffer from habitat loss due to increasing agriculture throughout their range, which coincides with increasing road mortality (Motta-Junior et al. 1996).  Observations on maned wolves in Paraguay revealed a high incidence of parasitism, indicating that disease may also be a contributing factor to the decrease in wolf populations (Meritt 1973).  They are classified as "low risk, near threatened" on the World Conservation Union (IUCN) red list, and are classified as "endangered" by the Brazilian government (Dietz 1985).

Maned wolves are a popular zoo animal.  It has been found that the diet of captive wolves has to be very carefully monitored to maintain a relatively high pH level in their urine.  If the pH falls below 7.5, wolves are susceptible to various urinary tract ailments.  This is unusual among carnivores, who typically display an acidic urinary pH due to their protein-heavy diets (Uka 1986).

Throughout most of its range, the maned wolf occurs sympatrically with two other canids; crab-eating foxes (Cerdocyon thous) and hoary foxes (Lycalopex vetulus), but differences in diet allow them to fill different niches (Juaraz and Marinho-Filho 2002).  All of these canids are important seed dispersers of the cerrado, or savanna-like grassland, habitat, as seeds remain intact after passing through the digestive tract (Juarez and Marinho-Filho 2002).

A hunting association has been observed between Aplomado falcons (Falco femoralis) and maned wolves; falcons were noticed following wolves while they hunted in cerrado, or savanna-like grassland, and opportunistically hunting prey animals that the wolves failed to capture (Silveira et al. 1997).  Another relationship has been observed between maned wolves, lobeira and ants, as wolves defecate the lobeira seeds on ant mounds.   Ants further disperse the seeds and use the fecal materials as fertilizer in their fungal cultivations (Courtenay 1994).

Literature Cited:

Aragona, M. and E. Z. F. Setz.  2001.  Diet of the maned wolf, Chrysocyon brachyurus (Mammalia: Canidae), during wet and dry seasons at Ibitipoca State Park, Brazil.Journal of Zoology 254:131-136.

Bestelmeyer, S. V.  1999.  Behavioral changes associated with introductions of male maned wolves (Chrysocyon brachyurus) to females with pups. Zoo Biology 18:189-197.

Bestelmeyer, S.V. and C. Westbrook.1998. Maned wolf (Chrysocyon brachyurus) predation on Pampas deer (Ozotoceros bezoarticus) in central Brazil.  Mammalia 62:591-595.

Bueler, L.E.1973. Wild Dogs of the World. Stein and Day, New York, NY.  Pp.274.

Courtenay, O.1994.Conservation of the maned wolf.  IUCN/SSC Canid Specialist Group's Canid News 2:41-43.

Dietz, J. M.  1984.  Ecology and social organization of the maned wolf (Chrysocyon bracyurus). Smithsonian Contributions to Zoology 392._________.  1985.  Chrysocyon brachyurus.  Mammalian Species 234: 1-4.

Juarez, K. M. and J. Marinho-Filho.2002. Diet, habitat use, and home ranges of sympatric canids in central Brazil. Journal of Mammalogy 83(4):925-933.

Kleiman, D. G.1972. Social behavior of the maned wolf (Chrysocyon brachyurus) and bush dog (Speothos venaticus): a study in contrast.  Journal of Mammalogy 53(4): 791-806.

Meritt, D.  1973.  Some observations of the maned wolf in Paraguay.  Zoologica 58(2):53.

Motta-Junior, J. C., S. A. Talamoni, J. A. Lombardi and K. Simokamaki.  1996.  Diet of the maned wolf, Chrysocyon brachyurus, in central Brazil.  Journal of Zoology 240:277-284.

Silveira, L., A. T. A. Jácomo, F. H. G. Rodrigues and P. G. Crawshaw, Jr.  1997. Hunting association between the Aplomado falcon (Falco femoralis) and the maned wolf (Chrysocyon brachyurus) in Emas National Park, central Brazil. Condor 99:201-202.

Uka, D.  1986.  Maned wolves- an account of a breeding season.  Thylacinus 11(4):2-10

Reference written by Melanie Hanson, Biol 378 (Mammalogy), University of Wisconsin – Stevens Point:  Edited by Christopher Luddington. Page last updated March 29, 2005.