Philippine Flying Lemur

The Philippine flying lemur has a strange appearance, and a strange name, as it is neither a true flier, nor a true lemur! It is in fact a rather unique gliding mammal that possesses a distinctive gliding membrane, or patagium, that stretches from the side of the neck to the tips of the fingers and toes, and down to the tip of the tail. The patagium stretches out into the shape of a kite and enables the Philippine flying lemur to glide through the forest for over 100 metres. The fur varies greatly in color and pattern, but generally males are some shade of brown and females are greyish. Both sexes have paler underparts and a shaded, mottled appearance that blends well with the bark of trees. The large eyes hint at the flying lemur’s nocturnal habits, and they also provide superior vision for accurately judging landings following a glide. The Philippine flying lemur has strong, sharp claws with which it anchors itself to a tree trunk or underside of a branch.

## Biology

Secretive and nocturnal, the Phillipine flying lemur spends the day in tree holes, or gripping a tree trunk or branch with its patagium extended over its body like a cloak. It has also been seen curled up in a ball among the palm fronds of a coconut plantation. It ventures out of its shelter at dusk, climbs a short distance up a tree and then glides off in search of food. It is capable of executing controlled glides of over 100 metres, with little loss in height. While gliding, the Philippine flying lemur is vulnerable to fast-flying birds of prey, such as the majestic Philippine eagle (*Pithecophaga jefferyi*). However, gliding is by far their most efficient method of locomotion; on the ground they cannot stand erect and are virtually helpless, and in the trees they are skilful, but very slow, climbers and move in a series of lingering hops.

The Philippine flying lemur feeds on the young, nutritious leaves from a wide range of trees. With its front foot, it pulls a branch towards itself, moving a bunch of leaves within reach. Its stomach is specially adapted for ingesting large quantities of leafy vegetation, but it also eats buds, flowers and perhaps soft fruits, and obtains sufficient water from its food and by licking wet leaves.

Gestation in the Philippine flying lemur lasts for around 60 days, after which the female gives birth to one, rarely two, young. They are born in an undeveloped state and carried on the mother, even as she glides, until they are weaned at six months. The patagium can be folded near the tail into a soft, warm ‘hammock’ in which the young can be carried. The Philippine flying lemur reaches adult size at two to three years of age.

## Habitat

The Philippine flying lemur is endemic to the southern Philippines. Its population is concentrated in the Mindanao region and Bohol. Colugos live in heavily forested areas, living mainly high up in the trees in lowland and mountainous forests or sometimes in coconut and rubber plantations, rarely coming down to the ground. The types of forests they inhabit are mainly primary and secondary forests.

## Physical Features

An average Philippine flying lemur weighs about 1.0 to 1.7 kg (2.2 to 3.7 lb) and its head-body length is 33–38 cm (13-15 inch). Its tail length is 17–27 cm (6.7-10.6 inch). The species does exhibit sexual dimorphism where females are a bit larger than males. It has a wide head and rostrum with a robust mandible for increased bite strength, small ears, and big eyes with unique photoreceptor adaptations adapted for its nocturnal lifestyle. The large eyes allow for excellent vision which the colugo uses to accurately jump and glide from tree to tree. It has an avascular retina which is not typical of mammals, suggesting this is a primitive trait; on par with other nocturnal mammals, specifically nocturnal primates, the rod cells in the eye make up about 95-99% of the photoreceptors and cones make up about 1-5%. Its clawed feet are large and sharp with an incredible grip strength, allowing them to skillfully but slowly climb trees, hang from branches, or anchor themselves to the trunk of a tree. One unique feature of the colugo is the patagium, the weblike membrane that connects its limbs to allow for gliding. Unlike other mammals with patagia, its patagium extends from the neck to the limbs, in between digits, and even behind the hind limbs and the tail. Its keeled sternum, which is also seen in bats, aids in its gliding efficiency. Its patagium is the most extensive membrane used for gliding in mammals and also functions as a hammock-like pouch for its young. This membrane helps it glide distances of 100 m or more, useful for finding food and escaping predators, such as the Philippine eagle (*Pithecophaga jefferyi*) and tree-climbing snakes that try to attack the colugos when they glide between trees. The dental formula of Philippine flying lemur is 2/3, 1/1, 2/2, 3/3, with a total of 34 teeth. The first two lower procumbant incisors are pectinate with up to 15 tines which are thought to be used for grooming and grating food. The upper incisors are small and have spaces between them, as well. The deciduous teeth are serrated until they are lost and then they are replaced with blade-like teeth, designed to shear along with the molars that also have long shearing crests to help break down the plant matter they ingest. Following mechanical digestion, the digestive tract of the Philippine flying lemur, especially the stomach, is specially adapted to break down and process the large amount of leaves and vegetation they ingest. Colugos also have a brownish grey-and-white pelage they use as camouflage amongst the tree trunks and branches, which allows them to better hide from predators and hunters.

## Diet

The Philippine flying lemur is a folivore, eating mainly young leaves and occasionally soft fruits, flowers, and plant shoots. They also obtain a significant amount of their water from licking wet leaves and from the water in the plants and fruits themselves. Most of their nutrition is obtained from jumping and gliding between trees high in the canopy; rarely do they eat on the forest floor.