Colugos are mammals from an ancient lineage and although they are sometimes called the flying lemurs, they are not closely related to the Lemurs of Madagascar. However, like the flying lemurs, they have developed an extensive membrane, known as patagium that attaches to their hands and feet, which help them to glide significant distances from tree to tree like the flying squirrels. But here again, unlike the flying squirrels, they do not have a free tail.
Generally, colugos are mottled grey or green-grey in color, but some specimens are reddish to yellowish-orange. Usually, they weigh between one and two kg and reach a length of 14 to 16 inches. The spaces between their fingers and toes are webbed like those of the bats, but they cannot fly like the bats, they can only glide and as proficient gliders, they can travel as far as 230 feet (70 m) from one tree to another without losing much altitude. They are smart gliders, but unskilled climbers, as they lack opposable thumbs and progress up trees in a series of slow hops, gripping onto the bark with their small and sharp claws. Colugos are relatively light built, having long, slender front and rear limbs and a medium-length tail. The head of a colugo is small, with small rounded ears and front-focused eyes with super binocular vision. They are equipped with unique incisor teeth, which have a comb-like texture and shape and each individual tooth has numerous grooves in it.
Like bats and flying squirrels, colugos are nocturnal and spend most of the day curled up in tree hollows or hanging inconspicuously under the branches. Their fur blends in with the tree and help them to become camouflaged from the predators like, pythons, yellow-throated martens, long-tailed macaques and owls. At the nightfall they become active, gliding from trunk to trunk. Their huge, glowing red eyes give them excellent night vision and depth perception, which help them to find their food. Colugos are strict herbivores and their diet includes leaves, flowers, fruits and young shoots, which they chew with their uniquely comb-shaped teeth. Colugos are equipped with long intestines and adaptable stomachs, which help them to extract nutrients from leaves and other fibrous materials of the plants, which are otherwise difficult to digest.
Colugos are placental mammals, but they raise their young somewhat like the marsupials. After a gestation period of 60 days, the females give birth to tiny and under developed babies weighing around 35 gm. They spend the first six months of their life clinging to their mother’s belly and the mother curls her tail and folds her patagium to keep them safe and warm as she glides. In fact, as their membrane is attached to their tail, they can fold it over and use it as a pouch. The mothers carry their underdeveloped and fragile-boned young along from tree to tree without any problem keeping them safe and secure. The young do not reach maturity until they are two to three years old.
Very little is known about the behaviour of the Colugos, as they are shy and solitary animals and mainly found in the tropical forests of Southeast Asia. They are found in Myanmar, Vietnam, Laos, Cambodia and Southern Thailand to Peninsular Malaysia, Singapore and the Indonesian islands of Sumatra and Java. They also occur throughout Borneo and a second Colugo species inhabit the southern Philippines. They live up to 15 years in captivity, but their lifespan in the wild is unknown.
Colugos are most threatened by habitat destruction. In addition to the ongoing clearing of their rainforest habitat, they are the soft targets of men and are killed for their meat and fur, which reflected the negative impact on their populations.