The Sunda Colugo: An Indonesian Native That's Neither a Monkey Nor a True Flyer

Native to the rainforests of Indonesia, Malaysia, and Thailand, the Sunda colugo (Galeopterus variegatus) confuses observers with its misleading name. Despite being called a "cat monkey" in some regions, this arboreal mammal belongs to the order Dermoptera—and rather than flying, it performs an astonishing glide that spans up to 100 meters between trees.

 

 

 

 

The colugo’s most remarkable feature is its patagium—a stretch of skin extending from its wrists to ankles, forming a parachute-like membrane that allows it to glide between trees. This adaptation, more efficient than the glides of flying squirrels, lets it navigate dense forests without descending to the ground. Contrary to its "monkey" label, it lacks a tail and has claws instead of grasping hands, resembling a large flying squirrel more than a primate. Its face, with large eyes and a rounded snout, gives it a cat-like appearance, hence the nickname "flying lemur"—though it’s unrelated to lemurs too.

Active at night, the Sunda colugo feeds on leaves, flowers, and tree sap, using its sharp teeth to scrape bark. It sleeps during the day, curled in tree hollows or under branches, relying on camouflage to avoid predators like clouded leopards and eagles. Despite its impressive gliding skills, it cannot generate lift like birds or bats, making it a master of controlled descent rather than true flight. Deforestation poses the gravest threat to colugos, as habitat fragmentation destroys their glide paths and food sources. Listed as Near Threatened by the IUCN, they depend on intact rainforests to survive—a reminder that Indonesia’s rich biodiversity includes creatures that defy easy classification.

For biologists, the Sunda colugo is a testament to evolutionary innovation: a mammal that conquered the canopy not by flying, but by perfecting the art of gliding. Its existence challenges our assumptions about taxonomic labels, proving that nature’s most fascinating creatures often thrive in the gaps between categories. As deforestation threatens its home, the colugo’s silent glide through the treetops serves as both a marvel of adaptation and a warning about the fragility of Earth’s unique species.