Bear cuscus  (Ailurops ursinus)

The bear cuscus is classified as Vulnerable (VU) on the IUCN Red List (1).

Named for its soft, dense pelage of black-greyish, bear-like fur, the bear cuscus (Ailurops ursinus) is a peculiar, yet distinctive marsupial (3). Adapted for a life high in the canopy, the bear cuscus has curved and sharply pointed claws and a long prehensile tail (2). The head is broad and flattened, with small, inconspicuous ears and a short snout (3). In common with many other marsupials, the female bear cuscus has a well-developed forward facing pouch on its belly, in which the poorly developed young suckle (2).  

The bear cuscus was formerly considered conspecific with the Talaud bear cuscus (Ailurops melanotis), but marked differences in pelage and size suggest that they are indeed separate species. Currently, four subspecies of the bear cuscus are recognised, each occurring on separate islands (4).

The bear cuscus is found on the island of Sulawesi, Indonesia and the neighbouring islands of Sangihe, Salidabu, Butung, the Peleng Islands, the Togian Islands, and possibly Muna (1) (5).

The bear cuscus inhabits lowland moist tropical rainforests, up to 600 metres above sea level. It prefers undisturbed forest and rarely enters degraded habitats (1). On Sangihe, the bear cuscus is largely restricted to undisturbed primary forest surrounding an extinct volcanic crater (5).

Despite its relatively large size and distinctive appearance, very little is known about the biology of the bear cuscus. However, it is believed to be the only diurnal member of its family, emerging at dawn to actively forage amongst the canopy for a variety of fresh leaves. Rather than jumping between trees, like the more acrobatic primates, the bear cuscus moves slowly, but efficiently, methodically placing each footstep (3). However, the bear cuscus spends the majority of its time resting, possibly because of the low nutrient quality of its diet (6).  Related species are typically solitary; however, the bear cuscus is more often found in pairs (2) (3). Partners communicate and advertise their position to other cuscuses using vocalisations and olfactory communication, often depositing secretions from glands in the skin (2).   

The bear cuscus is probably monogamous, producing a single young at a time. In common with other marsupials, the infant is very poorly developed when born, and largely develops in a pouch on the mother’s belly, where it suckles her milk. The quality of the milk changes as the infant develops, initially being high in carbohydrates, and later rich in fat. This unique adaptation allows the young to grow quickly, and females may reach maturity immediately after weaning (2).  

Favoured for its meat and fur, the bear cuscus is severely threatened by hunting. Despite once being common throughout its range, alarming declines of up to 95 percent have occurred in several areas, most notably the Tangkoko-DuaSudara Nature Reserve on Sulawesi (1). Surveys on Sangihe and Salidabu found that 57 percent of interviewed famers hunted the bear cuscus, using rifles, blowpipes and nets, and hunting is likely to have been the cause of several local extinctions. This threat is compounded by the logging and degradation of lowland rainforests, home to the bear cuscus (1) (5). Around 56 percent of Sulawesi was forested in 1988, but since then much of the lowland forests, growing upon fertile volcanic soils, have been cleared for agricultural projects, such as sugar-cane plantations. Consequently, much of the remaining forest is unsuitable for the bear cuscus, as it is at higher altitudes (7).

Although protected by Indonesian Law, and occurring in several protected areas, hunting and habitat loss continue to endanger the bear cuscus, and efforts are required to tackle the threats to this rare species (1). Proposed conservation measures include the creation of a special police task force responsible for monitoring hunting, the creation of additional protected areas, and the development of community awareness programmes, aiming to highlight the plight of the bear cuscus (5) (7).

The island of Sulawesi is an area of high conservation importance, with over 120 mammals species, 62 percent of which are endemic, and the protection of its forests will undoubtedly preserve the populations of many rare species. Recognising this, the Wildlife Conservation Society (WCS) is working to promote legal enforcement and prevent wildlife trade through its Sulawesi Wildlife Crime Unit, and by monitoring major roads that connect wildlife markets to hunting-fields. With the Indonesian government, WCS is also providing training to park officials and is helping to develop management plans for protected areas (8).

View information on this species at the UNEP World Conservation Monitoring Centre.

For more information on conservation in Sulawesi: 

• Wildlife Conservation Society:
  http://www.wcsip.org/