Prevost's Squirrel

Prevost's squirrel, also called the Asian tri-coloured squirrel, is a colourful rodent of the family Sciuridae found in forests of the Thai-Malay Peninsula, Sumatra, Borneo and nearby smaller islands, with an introduced population in northern Sulawesi. The head and body are typically 20 to 27 cm (8 to 11 in) long, with a tail of about the same length. The typical form has black upperparts and tail, reddish-orange underparts, whitish thighs and flanks and grey cheeks. It is active by day, stays mostly in trees and only occasionally moves on the ground. It eats fruits, nuts, seeds, buds, flowers, insects and bird eggs, and often visits plantations or gardens.

About the Prevost's squirrel

Prevost's squirrel is a medium-sized tree squirrel of Southeast Asia's rainforests, found on the Thai-Malay Peninsula, Sumatra, Borneo and nearby islands. It belongs to the squirrel family, Sciuridae, and the Asian genus Callosciurus. Its typical coat of black, chestnut-red and white makes it one of the most colorful mammals in the world.

Its scientific name is Callosciurus prevostii, and it also goes by Asian tri-colored squirrel, ornamental squirrel and beautiful squirrel. It is one of the larger squirrels in its range, though the region's giant squirrels and giant flying squirrels are clearly bigger. Head-and-body length is typically 20 to 27 cm (8–11 in), the tail is about as long again, and adults weigh 250 to 500 g (9–18 oz).

The classic form, found on the Thai-Malay Peninsula, has black upperparts and tail, reddish-orange underparts, whitish thighs and flanks, and grey to grey-white cheeks. A white stripe often separates the black back from the chestnut belly, and many subspecies carry a prominent shoulder patch that can be black, grey, red, white or a mix. The fur is usually thick but not soft.

Color varies enormously across the islands. The underparts are always reddish-orange to rich rufous, but some Bornean forms have grey or olive-grey thighs, orange cheeks, or grizzled upperparts. Some forms elsewhere look much like the peninsular type, such as the grey-cheeked C. p. rafflesii of southern Sumatra and the black-cheeked C. p. melanops of eastern Sumatra. Four subspecies, from northern Sumatra, northeastern Borneo, Labuan and Banggi, are simply black above and rich rufous below, with no white at all. As many as 44 subspecies have been named. A 2005 reference recognized only 6, while a 2012 work recognized 32, and no detailed modern review has settled the question. Island size also matters: squirrels from small islands tend to be smaller than those from medium-small islands, but on large islands the pattern reverses.

Behavior and diet

Prevost's squirrel is active by day, with its busiest periods around dawn and dusk, making it a diurnal animal with a crepuscular peak. It spends most of its time in trees and only occasionally comes down to the ground. It can be seen in groups while feeding in fig trees.

The diet is mostly plant-based. Prevost's squirrels eat fruits, nuts, seeds, buds and flowers, along with insects such as ants, termites and beetle larvae, and bird eggs. Staples include coconut, rubber seeds, oil palm fruit and soft fruits such as figs. They have been seen feeding on durians, including Durio graveolens. One squirrel was observed trying to wedge a ripe fruit into a crack in a branch, a hint that the species may cache food.

That fruit-eating habit makes the squirrel a seed disperser. It often carries fruit well away from the parent tree, eats the flesh, and drops the seeds. Seeds carried away like this may face a lower risk of being eaten than those left under the parent tree, which helps the fruiting plant.

Breeding happens year-round, with a peak between June and August. Gestation is about 40 to 48 days, or roughly six to seven weeks. In captivity, females have 1 to 4 young, averaging 1.8, and newborns weigh only about 16 g (0.6 oz). The nest is built in a tree hollow or made from sticks, bark, leaves, twigs and grass. In central Malaysia, pregnancy rates track the amount of rainfall. Juveniles have never been seen foraging for themselves, and adults may provide them with seeds.

Prevost's squirrels communicate largely through touch and scent. Their anti-predator behavior has not been reported, though a related species, Callosciurus caniceps, is known to have an alarm call.

Little is known about predators. A yellow-throated marten has been seen chasing a Prevost's squirrel, and a crested serpent eagle has been seen carrying one.

Range and habitat

The species ranges across the Thai-Malay Peninsula, with its northern limit in southern Thailand, through Malaysia, Sumatra, Borneo and many smaller islands of the region. An introduced population lives in northern Sulawesi.

Its home is tropical rainforest, where it nests in tree hollows or builds its own nest of leaves and twigs. In northern Borneo, Prevost's squirrels use smaller trees of the middle story in primary forest and old logged forest. In western Malaysia they have been found feeding on figs in the upper story. They can also live in somewhat disturbed habitat and often visit plantations and gardens.

That flexibility has a downside. Where forest has been converted to agriculture, the squirrels develop a taste for oil palm nuts, which brings them into conflict with plantation owners.

Conservation status

Prevost's squirrel is listed as Least Concern on the IUCN Red List (2016). It has no special CITES status. It generally remains common and widespread, which is why it is not considered threatened.

That does not mean every population is doing well. The species is declining in some regions because of habitat loss and hunting, and the pet trade may also reduce numbers. Many of the forests it depends on, including the Peninsular Malaysian rainforests and the Sumatran lowland rainforests, are themselves considered vulnerable or critically endangered as habitats.