Night Explorers of Kemuning: Sunda Colugo

This nocturnal explorer is one of the many species that enliven the quiet nights of Kemuning Forest, Temanggung, Central Java. This gliding mammal has distinct characteristics compared to others such as the giant flying squirrel (Petaurista petaurista pallas) and the flying squirrel (Iomys horsfieldii) mentioned in previous posts. The Sunda colugo, locally known as kendung in Kemuning Forest, has the scientific name Galeopterus variegatus.

The Sunda colugo is a nocturnal gliding mammal that spends most of its life in trees (arboreal). Adult colugos weigh between 925–1,750 grams, with a head-body length of about 33–42 cm (13–17 inches).

Its tail length ranges from 18–27 cm (7.1–10.6 inches). The Sunda colugo is well camouflaged, as its body color resembles tree bark. It moves from one tree to another by gliding, using a membrane covered with fur called a patagium. This membrane extends between the head and forelimbs (propatagium), between the forelimbs and hindlimbs (plagiopatagium), and between the hindlimbs and tail (uropatagium), even covering its digits.

Male and female colugos can be distinguished by fur coloration, observations during gliding (presence or absence of testes), and whether an individual is carrying an infant. Males tend to have lighter, darker-brown coloration, while females appear more grayish.

Behavior

The Sunda colugo becomes active at dusk and remains active until before sunrise, making it a nocturnal species. It can live solitarily or in small groups with a male-to-female ratio of approximately 1:3, particularly during the mating season.

Most of its time is spent resting in trees, either clinging to trunks or hanging from branches. It is commonly found attached to the main trunk or hanging on the first branches near the trunk.

Colugos forage and avoid predators by gliding from one tree to another. Gliding may begin by climbing vertically up the trunk to gain height or directly from a branch. By spreading its patagium, the colugo can glide horizontally for distances of up to 150 meters.

Infant colugos are usually found clinging to their mother’s abdomen. Females carrying young tend to be more passive and glide less, preferring trees with abundant food (large trees with dense canopies), while males move more frequently between trees.

Diet

The Sunda colugo is often described as folivorous, as it primarily feeds on leaves. However, it is also considered omnivorous. In Malaysia, colugos have been observed licking ants from tree holes.

Their diet includes leaves, young fruits, flowers, shoots, sap, and small insects.

In Kemuning Forest, colugos have been observed feeding on leaves from peleman (Buchanania arborescens), jackfruit (Artocarpus heterophyllus), lamtoro (Leucaena leucocephala), jengkol (Archidendron pauciflorum), wild guava (Syzygium cumini), as well as leaves and flowers of salam (Syzygium polyanthum), young kapok fruits (Ceiba pentandra), and sap from putat (Litsea velutina).

Geographic Distribution and Habitat

The Sunda colugo is widely distributed across Southeast Asia, including Peninsular Malaysia, Sabah, Sarawak, Singapore, Myanmar, Thailand, southern Vietnam, and parts of Indonesia (Sumatra, Java, Borneo, and Bali).

In Java, it has been recorded in West Java, including Pangandaran Nature Reserve, and in East Java, such as Meru Betiri National Park.

In Central Java, its presence has been documented in Kemuning Forest, Temanggung. The species can inhabit both lowland and mountainous areas, including primary forests, secondary forests, coconut plantations, rubber plantations, and forests below 100 meters above sea level.

Reproduction

The reproductive period is not precisely known, but gestation is estimated to last around 180 days. Typically, a colugo gives birth to a single offspring. The young stays with the mother for about six months and reaches maturity at around two years of age.

Ecological Role

As a consumer of young fruits and flowers, the Sunda colugo contributes to seed dispersal and pollination.

Conservation Status

According to the IUCN, the Sunda colugo is classified as Least Concern.

References

Beatson, K. 2011. “Galeopterus variegatus” (Online), Animal Diversity Web.

Byrnes, G., Libby, T., Lim, N.T.-L. & Spence, A.J. 2011. Gliding Saves Time But Not Energy in Malayan Colugos. Journal of Experimental Biology.

Byrnes, G., Lim, N.T.-L. & Spence, A.J. 2008. Take-off and Landing Kinetics of a Free-Ranging Gliding Mammal. Proceedings of the Royal Society B.

Dzulhelmi, M.N. & Suriyanti, S.N.P. 2013. Behaviour of the Sunda Colugo in Bako National Park. Journal of Science and Technology in Tropics.

Jackson, S.M. & Schouten, P. 2012. Gliding Mammals of the World. Smithsonian Contributions to Zoology.

Sulistiowati, Dewi. 2019. Feeding Behavior of Sunda Colugo in Kemuning Forest, Temanggung, Central Java. Undergraduate Thesis. Faculty of Forestry, Universitas Gadjah Mada.