The colugo, often inaccurately called a flying lemur, is a gliding mammal native to the forests of Southeast Asia. This unique creature comprises the entire mammalian order Dermoptera. Its name, derived from Greek words meaning “skin wing,” refers to the extensive membrane of skin, called the patagium, which allows it to glide between trees. Colugos are arboreal and nocturnal, relying on a specialized diet of tough foliage.
Primary Plant-Based Diet
Colugos are herbivores, specifically folivores, meaning that leaves form the bulk of their food intake. Their diet consists primarily of soft plant parts, including young leaves, tender shoots, and flowers, which are more easily digestible than older, tougher foliage. The preference for young leaves is a nutritional strategy, as new growth contains higher concentrations of protein and lower levels of indigestible fiber and plant toxins. They also supplement this diet by consuming other plant structures, such as nectar, buds, and soft fruits, when these are seasonally available. The Sunda colugo (Galeopterus variegatus) has been observed to feed on sap, which provides a concentrated source of sugars and minerals.
Specialized Feeding Adaptations
The colugo possesses unique anatomical features that enable it to efficiently process its fibrous, leaf-based diet. The most distinctive feature is the structure of its lower incisor teeth, which are pectinate, or comb-like. Each lower incisor is divided into as many as 20 fine tines, creating a dental tool unlike any other found in mammals. These comb-like incisors function in grooming and food procurement, helping to scrape plant matter or extract pulp from soft fruits. The molars are also specialized, featuring well-developed ridges and cusps suited for grinding coarse plant material into a digestible paste.
The colugo’s digestive tract is adapted for high-fiber intake, featuring a well-developed stomach and long intestines. Like other leaf-consuming herbivores, the colugo relies on a process called hindgut fermentation. This digestive method uses a large chamber, the cecum and colon, where symbiotic microbes reside to break down the tough cellulose found in plant cell walls. Microbial fermentation produces volatile fatty acids that the animal absorbs for energy, allowing the colugo to extract maximum nutritional value from its food.
Ecological Factors Influencing Food Choice
The colugo’s arboreal and nocturnal lifestyle dictates its foraging strategy and food selection. Being active only at night limits them to food sources high in the forest canopy, where they spend nearly their entire lives, utilizing gliding to travel efficiently between scattered resources. The availability of specific plant species impacts the diet, which varies slightly between the two main species. Both the Philippine colugo (Cynocephalus volans) and the Sunda colugo feed on common canopy flora, such as Ficus (fig) trees and Eugenia (clove) trees; the Sunda colugo often forages in secondary forests and plantations, suggesting flexibility in its food choices. Colugos rarely descend to the forest floor, obtaining most necessary hydration directly from the moisture content of the leaves they consume, or by licking dew or rainwater that collects on foliage during nocturnal foraging.