Dusk is falling on the forests of Southeast Asia. The calls of insects fill the humid air. Daytime creatures are settling down for the night; birds rest on their perches and monkeys huddle together high in the forest canopy, but nocturnal animals are just beginning to stir.
A large shape glides across a gap in the trees, but this is no bird. Instead, it is a reclusive mammal known as a colugo. Skin flaps extended, the colugo swoops in for a landing on a nearby tree, its grey-brown mottled fur camouflaging it nearly perfectly with the tree’s bark. As the colugo settles in on the tree, a small head peeks out from underneath its mother’s furry gliding skin, taking in the darkening forest through huge round eyes.
David. (2022). [Colugo mother and baby, Photograph]. Incidental Naturalist. https://incidentalnaturalist.com/2022/03/26/sunda-colugo-the-flying-lemur/
Colugos are nocturnal, tree-dwelling mammals found only in Southeast Asia. They are also known as flying lemurs, but this name is misleading as colugos are not lemurs and do not actually fly (instead they glide from tree to tree). Colugos are most closely related to primates, separating from primates about 80 million years ago. They are especially unique because they are the only species in their family, Cynocephalidae, and order, Dermoptera.
There are two species of colugos, which are very similar physically and behaviorally, but inhabit different areas of Southeast Asia. The Malayan colugo (Cynophalus variegatus), also known as the Sundra colugo, lives in an area ranging from Vietnam to Indonesia, while the Philippine colugo (Cynocephalus volans) lives on islands in the Southern Philippines. However, recent analyses suggest that the genetic differences between different groups of colugos may be significant enough to split Sunda colugos into 8 or 14 different species.
Adult colugos are about the size of a cat with a body length between 13 - 16.5 in, a tail length between 8 - 11 in, and a weight between 2 - 4 lb. Their broad head is slightly lemur-like with a blunt muzzle, short, rounded ears, and large eyes. They have sharp claws, helping them climb trees or hang, camouflaged, on the bark of trees, as they sleep during the day.
However, the most unique feature of a colugo is its large gliding membrane, called a patagium. The patagium of colugos is larger than those of other gliding mammals, extending all the way from their neck to the tip of their tail. This enables them to glide further without losing as much height. In fact, colugos have been observed gliding as far as 145 meters (476 ft), the length of 3 Olympic swimming pools. Muscles in their patagium allow colugos to change its stiffness and shape to adjust their flight paths.
Composite of a colugo mother coming in for a landing with a baby colugo clinging to her underside.
Lee, C. C. (2020). [Colugo Landing, Composite Photograph]. Science News. https://www.sciencenews.org/article/colugo-flying-lemur-mammal-southeast-asia
Between glides, colugos must climb further up the tree to regain lost altitude. Their lack of opposable thumbs and their large patagium makes climbing difficult, so they must progress up the tree in a series of slower hops. The energy expenditure of the climb means that gliding does not save colugos energy, but it does save them time, giving them more time to feed or travel longer distances.
Colugos eat mostly leaves but also feed on shoots, buds, flowers, and even sap. They have a very unique dental structure, which includes two pairs of comblike lower incisors. The purpose of these teeth is not fully understood, but they may be used to scrape up and strain sap or to groom their fur.
Colugos interact in fluid social groups of females or a mother and her offspring (including those already weaned). Male colugos are mostly solitary but occasionally come into contact with groups of females. Colugos likely vocalize using ultrasound, noises too high for human ears.
After a gestation period of about 60 days, mother colugos give birth to a single offspring. Colugos are born tiny and underdeveloped, weighing only around 35 g (1.2 oz) at birth. Mothers will carry the baby colugos for around 6 months, nestled under her patagium when she is on trees or clinging to her stomach as she glides. Even though they are weaned at 6 months, it takes young colugos 2-3 years to reach their adult size.
Both species of colugos are categorized as “least concern” by the International Union for Conservation of Nature (ICUN) but are threatened by both deforestation and hunting. Even though they are not in danger overall, certain subgroups of colugos (which may turn out to be distinct species) may be threatened by local extinction. Colugos can adapt well to living alongside people near villages—as long as there are enough trees. In fact, many locals are not even aware of the presence of colugos as they are nocturnal and well-camouflaged during the day.
With a little protection, these unique animals can continue to thrive, gliding through the forests of Southeast Asia.
Night Spotting Project. (2020). [Colugo, Photograph]. Science News. https://www.sciencenews.org/article/colugo-flying-lemur-mammal-southeast-asia
About the Author
Marcella is a Senior at Northwood High School who is interested in a career as a Conservation Biologist. She enjoys reading, playing the piano, and being outside.
Sources
Law, Y. H. (2020, November 20). On a cool night in Malaysia, scientists track mysterious
colugos across the treetops. Science News. https://www.sciencenews.org/article/colugo-flying-lemur-mammal-southeast-asia
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Macdonald, D. W. (Ed.). (2006). Colugos. In The Encyclopedia of Mammals (3 ed., 432-433).
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David. (2022, March 26). Sunda Colugo – The Flying Lemur. Incidental Naturalist, Word Press.
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