Black Giant Squirrel Ratufa bicolor
The beautiful Black Giant Squirrel is one of the largest
squirrels in the world. It inhabits tall primary forest and generally remains
high in the canopy, but at times may be found at lower levels when feeding. It
is largely solitary in habits and extremely shy, rarely coming to ground. It can
confidently make huge leaps from branch to branch in the high canopy.
Its upperparts and tail are jet black, but the cheeks, chest, front of the forelimbs and underparts are cream or orange. The tail is long and dorso-ventrally flattened. Fruits, seeds and young leaves make up its diet, supplemented by occasional insects and sometimes birds eggs. It builds a large, spherical nest of leaves and twigs. The species once ranged extensively from Nepal and Assam through Burma, Indochina and Thailand to Peninsular Malaysia, Sumatra, Java and Bali. Its numbers have declined with the large-scale clearance of primary forest. It is absent from Singapore.
Head and body length varies from 35 to 58 centimetres (14 to 23 in) in length, and the tail is up to 60 centimetres (24 in) long, with an overall length of up to 118 centimetres (46 in). The back, ears and bushy tail are deep brown to black with a lighter buff-coloured belly. The upperparts are black or dark brown and the underparts range from buff to orange colour. The buff throat and cheeks are separated by a thick moustache mark. The top of the head is black. There are 2 dark spots on the chin. The under fur of the dorsum is reddish brown, and the under parts especially the rump and crown are often tinged reddish brown. The hairs on the underparts have black bases. In sum subspecies there is a bluff or white patch, called a flash mark between the wrist and elbow of the upper surface of the foreleg. The rest of the upper surface of the foreleg is black or dark brown. The female as tree pairs of mammae.
The population of this species is declining in South Asia, but
the rate of decline is unknown (Molur et al. 2005). In Lao PDR, Vietnam and
Thailand the species is abundant in
suitable habitat where hunting is controlled. It is easily eradicated from
fragmented habitat (Duckwoth pers. comm.). In Lao PDR it is recorded from most
survey areas; however, populations are now so low in some areas that it has not
been recorded in recent surveys, including Sangthong District, Nam Et and Phou
Louey NBCAs (Duckworth et al. 1999). It was found to be locally common during a
survey in 1994-95 of the Nadi Limestone area in Lao PDR by Evans et al. (2000).
It is still widespread and abundant in Cambodia, largely as hunting has not yet
impacted populations in this country (R. J. Timmins pers. comm.). This species
was rarely found in a survey conducted by Saiful and Nordin (2004) in Peninsular
Malaysia (Weng River catchment area). This species is rare and declining on
Java, where it is found only in remote areas (away from human habitation) within
remaining patches of forest (primary and secondary) (Boeadi pers. comm.). This
species is declining in population, in parallel with forest loss on Java (Boeadi
Population Trend: Decreasing
Ratufa bicolor's range includes a variety of bioregions that all share the commonality of being forested. It ranges in elevation from sea level up to at least 1,400 metres (4,600 ft), in some of the most rugged land in the world. However, in recent decades, R. bicolor's habitat has been steadily encroached upon by human settlement, timber harvesting and agriculture, which along with over hunting by human predation in parts of its range, has resulted in a total loss of up to 30% of the population in the past ten years. However, in some places this species is protected from hunting by law or tradition.
In South Asia R. bicolor dwells among tropical and subtropical coniferous and broadleaf forests. In Southeast Asia R. bicolor lives in tropical broadleaf evergreen and semi-evergreen forests, but is rarely seen in coniferous forests. In the tropical rainforest of the Malay Peninsula and Indonesia, R. bicolor is not as abundant as elsewhere in its range, which is probably due to competition from other arboreal species (especially primates) for food in the upper forest canopy. Among the better places to sight the black giant squirrel is the Kaziranga National Park in the state of Assam, India.
R. bicolor is diurnal and arboreal, but sometimes climbs down from the forest canopy to feed on the ground. The black giant squirrel rarely enters plantations or settlements, preferring the wild forest.
Its diet consists of seeds, pine cones, fruits and leaves, but will eat small insects and birds eggs. It is primarily solitary, and has a litter of from 1 to 2 young, which it raises in a drey (or nest), often located within a hollow space of a tree. This is a shy forest species which very rarely enters the ground and remains in the canopy. It moves through the canopy making long leaps of 20 feet or more. When feeding it assumes a conspicuous posture. It hangs across a branch with its foreparts on one side and its long black tail across the other . The nest is built on thin branches on the highest part of a tall tree for protection from predators where a nest is constructed of twigs and leaves. Medway (1969) described the voice as being a loud, resonant, bubbling chatter, Chak, Chak, Chak, repeated and with a quieter note Ch'k, Ch'k. It is know to live for 11 years in captivity. It is not tolerant of habitat modification, and has a long generation time of eight to nine years, with a litter size of one or two young.
Human induced habitat degradation due to shifting (jhum) agriculture practices, small-scale logging, clear-cutting, forest fires, expansion of human settlement, harvesting for local consumption have been observed to be major threats for this species in South Asia (Molur et al. 2005). It is threatened by hunting and habitat loss in China (Wang et al. 1989). This species is especially vulnerable to hunting and habitat loss (often through logging operations) in Lao PDR (Evans et al. 2000), Vietnam and Thailand. This species was "formerly one of the most commonly sold mammals in the That Luang fresh food market in Vientiane" (Duckworth et al. 1999). Hunting pressure is predicted to increase in Cambodia, as following the over harvesting of large bodied mammals, smaller species are now being targeted (W. Duckworth pers. comm.). It is not hunted on Java, as people are generally aware of the legislation protecting this species; however, habitat loss remains a considerable threat (Boeadi pers. comm.).
The species is included in the Schedule II (Part II) of the Indian Wildlife (Protection) Act, 1972. It is known from the following protected areas in India and Bangladesh - India: Eagle's Nest Wildlife Sanctuary, Kamlang Wildlife Sanctuary, Mehao Wildlife Sanctuary, Namdapha National Park, Pakhui Wildlife Sanctuary, Tale Valley Wildlife Sanctuary in Arunachal Pradesh, Buxa Tiger Reserve, Gorumara Wildlife Sanctuary, Jaldapara Wildlife Sanctuary, Mahananda Wildlife Sanctuary in West Bengal; Bangladesh: Lawachara National Park (Molur et al. 2005). Survey, life history, limiting factors studies and monitoring are recommended for this species in South Asia (Molur et al. 2005). In Southeast Asia, it occurs in a number of protected areas throughout its range, including Gunung Masigit Kareumbi Hunting Park, Pananjung Pangandaran Nature Reserve, and Ujong Kulon National Park in Java (Boeadi pers. comm.). Saiful and Nordin (2004) state the need for further comparative study on this species' abundance, density and distribution and its relationship to forest structure or habitat quality, spatially and temporally, in hill dipterocarp forest of Malaysia. This species is protected from hunting by legislation in Java (Boeadi pers. comm.). It is listed on CITES Appendix II regulating international trade in this species.