The Bush Dog Is Characterised By An Elongate Body

The bush dog is characterised by an elongate body, a short and sometimes stubby tail, broad face with short muzzle, small rounded ears, brown eyes, and short leg. Head and neck are generally reddish/tan or tawny, gradually darkening to black or dark brown hindquarters and legs. The underside is also dark and some individuals may show a pale white throat or chest patch. Coat patterns can, however, be highly variable, ranging from almost all black to very light blonde. Feet are partially webbed and tracks are nearlyidentical to those of the domestic dog. Bush dogs are one of three canid species with trenchant heel dentition, a unicuspid talonid on the lower carnassial molar that increases the cutting blade length. Dental formula is 3/3-1/1-4/4-2/2=40.

The bush dog is accepted as the sole extant representative of the monotypic genus Speothos. Speothos pacivorus Lund, 1839, an extinct species, is known only from fossil deposits discovered at the Lagoa Santa caves in Minas Gerais, Brazil, and may not have existed past the Holocene (Berta 1984). This is the same site for the type locality specimen of S. venaticus. The two species are distinguished by several dental features, including the presence of a metaconule and hypocone on M1, a large, double-rooted M2, as well as the larger size of S. pacivorus (Berta 1987). A third species, S. major (Lund 1843), is now considered synonymous with S. venaticus.

The taxonomic relationship of bush dogs to other canids remains debatable. The presence of a unicuspid M1talonid led to the inclusion of the bush dog in the subfamily Simocyoninae, along with two other species that share this characteristic, the African wild dog (Lycaon pictus), and dhole (Cuon alpinus). Berta (1984, 1987) suggested bush dogs are most closely related to small-eared dogs (Atelocynus microtis), and members of the Cerdocyon clade (one of four monophyletic groups of South American canids). This group includes the raccoon dog (Nyctereutes procyonoides). Berta (1987) suggests a single ancestor for this group, ranging over Eurasia and North America, with isolation of the raccoon dog occurring when the Bering Land Bridge disappeared. Recent molecular analyses, based on mitochondrial DNA, suggest bush dogs and maned wolves (Chrysocyon brachyurus) constitute a monophyletic group distinct from other South American canids.

Habitat

Bush dogs are reported to be a habitat generalist by indigenous peoples, within the context of occurring generally near water sources, particularly small streams, and near available prey populations, especially Agoutipaca (O. Carrillo and M. Swarner pers. obs.). Bush dogs have been observed in lowland (below 1,500m a.s.l.) forested habitats including primary and gallery forest, semi-deciduous forest, and seasonally flooded forest (Aquino and Puertas 1997). Observations have also been recorded from cerrado habitat in Brazil(Silveira et al. 1998; C. Brady pers. comm.) and Paraguay (Zuercher and Villalba 2002) and pampas (wet savannah) edge/riparian areas (Strahl et al. 1992; Emmons 1998). In some cases, they have been observed as far as 5,700m from forest habitat (Silveira et al. 1998). The species is also occasionally reported from secondary forest, ranchland (M. Swarner pers. obs.) and fragmented cerrado ranchland (L. Silveira and A. Jácomo pers. comm.).