Perception Channels: tactile ; chemical
Other Physical Features: endothermic ; bilateral symmetry
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual
It is now widely (if not universally) accepted that the two extant species in the mammalian order Dermoptera, along with the Scandentia (tree shrews), are the closest living relatives of the Primates, although the precise relationships among these three groups remain a matter of some debate (Janečka et al. 2007; Arnason et al. 2008; Nie et al. 2008; Asher et al. 2009). These three groups together are sometimes referred to as the Archonta (or Euarchonta) (Asher et al. 2009; Asher and Helgen 2010).
Dermopterans are commonly known as flying lemurs or colugos. Just two species of colugos are currently recognized, the Philippine Colugo (Cynocephalus volans), found only in the southern Philippines, and the Sunda Colugo (Galeopterus variegates). The Sunda Colugo is endemic to Indochina and Sundaland, an area of the Asian continental shelf that includes the Malay Peninsula and the large islands of Borneo, Sumatra, and Java, as well many smaller islands. Janečka et al. (2008) investigated genetic variation in this broadly distributed species. Based on results from both mitochondrial and nuclear genetic loci, in combination with morphological analyses, they argue that mainland, Javan, and Bornean colugo subspecies may be better recognized as distinct species rather than as subspecies within a single species. (Janečka et al. 2008)
Colugos have a large gliding membrane attached to the neck and sides of the body. This membrane, which extends along the limbs to the tips of the fingers, toes, and tail, is more extensive than in other gliding mammals, whose gliding surface is only stretched between the limbs, with fingers, toes, and tail left free. Colugos are completely arboreal, being nearly helpless on the ground, and are able to travel over 100 meters forward in a single glide, with relatively little loss in elevation. They are generally nocturnal and feed on leaves, buds, flowers, and fruit. (Nowak 1991)
Lim and Ng (2010) estimated the population density of Sunda Colugos in the protected forests of Singapore at around one animal per two hectares, yielding an estimate of roughly 1000 individuals across Singapore's 2000 hectares of protected forest. Lim and Ng note that although colugos have been known to science for two centuries, they have been the subject of remarkably few formal studies. The investigation by Lim and Ng of appropriate methods for estimating population size of these animals is intended in part to facilitate further studies of the biology of these animals.
Colugos (/kəˈluːɡoʊ/)[2][3] are arboreal gliding mammals that are native to Southeast Asia. Their closest evolutionary relatives are primates. There are just two living species of colugos: the Sunda flying lemur (Galeopterus variegatus) and the Philippine flying lemur (Cynocephalus volans). These two species make up the entire family Cynocephalidae (/ˌsaɪnoʊˌsɛfəˈlaɪdi, -ˌkɛ-/)[4] and order Dermoptera (not to be confused with Dermaptera, an order of insects known as earwigs).
Despite being called "flying lemurs", the colugos do not fly and are not lemurs, although related. Instead, they glide as they leap among trees. They are the most capable gliders of all gliding mammals. A fur-covered membrane, called a patagium, connects to the face, paws, and tail. This enables them to glide in the air for distances of up to 200 metres (660 ft) between trees.[5] They are also known as cobegos.
Colugos are nocturnal, tree-dwelling mammals.
They reach lengths of 35 to 40 cm (14 to 16 in) and weigh 1 to 2 kg (2.2 to 4.4 lb).[6] They have long, slender front and rear limbs, a medium-length tail, and a relatively light build. The head is small, with large, front-focused eyes for excellent binocular vision, and small rounded ears.
The incisor teeth of colugos are highly distinctive; they are comb-like in shape with up to 20 tines on each tooth. The incisors are analogous in appearance and function to the incisor suite in strepsirrhines, which is used for grooming. The second upper incisors have two roots, another unique feature among mammals.[7] The dental formula of colugos is: 2.1.2.33.1.2.3
Colugos are proficient gliders, and they can travel as far as 70 m (230 ft) from one tree to another without losing much altitude,[8] with a Malayan colugo (Galeopterus variegatus) individual having travelled about 150 m (490 ft) in one glide.[9]
Of all the gliding mammals, colugos have the most perfected adaptation for flight. They have a large membrane of skin that extends between their paired limbs and gives them the ability to glide significant distances between trees. This gliding membrane, or patagium, runs from the shoulder blades to the fore paws, from the tip of the rear-most fingers to the tip of the toes, and from the hind legs to the tip of the tail.[7] The spaces between the colugo's fingers and toes are webbed. As a result, colugos were once considered to be close relatives of bats. Today, on account of genetic data, they are considered to be more closely related to primates.[10]
Colugos are unskilled climbers; they lack opposable thumbs.[11] They progress up trees in a series of slow hops, gripping onto the bark with their small, sharp claws. They spend most of the day resting. At night, colugos spend most of their time up in the trees foraging, with gliding being used to either find another foraging tree or to find possible mates and protect territory.[12]
Colugos are shy, nocturnal, solitary animals found in the tropical forests of Southeast Asia. Consequently, very little is known about their behavior. They are herbivorous and eat leaves, shoots, flowers, sap, and fruit. They have well-developed stomachs and long intestines capable of extracting nutrients from leaves and other fibrous material.
Colugos have evolved into a nocturnal species, along with the ability to proficiently see during the nighttime.[13] Colugos spend their days resting in tree holes and are active at night time; traveling around 1.7 km at night. Colugos may also be a territorial species.
Although they are placental mammals, colugos raise their young in a manner similar to marsupials. Newborn colugos are underdeveloped and weigh only 35 g (1.2 oz).[14] They spend the first six months of life clinging to their mother's belly. The mother colugo curls her tail and folds her patagium into a warm, secure, quasipouch to protect and transport her young. The young do not reach maturity until they are two to three years old.[7] In captivity, they live up to 15 years, but their lifespan in the wild is unknown.[15]
Both species are threatened by habitat destruction, and the Philippine flying lemur was once classified by the IUCN as vulnerable. In 1996, the IUCN declared the species vulnerable owing to destruction of lowland forests and hunting. It was downlisted to least-concern status in 2008 but still faces the same threats. In addition to the ongoing clearing of its rainforest habitat, it is hunted for its meat and fur. It is also a favorite prey item for the critically endangered Philippine eagle; some studies suggest colugos account for 90% of the eagle's diet.[16]
The Mixodectidae and Plagiomenidae appear to be fossil Dermoptera. Although other Paleogene mammals have been interpreted as related to dermopterans, the evidence for this association is uncertain and many of the fossils are no longer interpreted as being gliding mammals.[17] At present, the fossil record of definitive dermopterans is limited to two species of the Eocene and Oligocene cynocephalid genus Dermotherium.[18]
Recent molecular phylogenetic studies have demonstrated that colugos emerged as a basal Primatomorpha clade which is a basal Euarchontoglires clade. Treeshrews (order Scandentia) emerged as sister of Glires (lagomorphs and rodents), in an unnamed sister clade of the Primatomorpha.[19][20]
EuarchontogliresScandentia (treeshrews)
GliresRodentia (rodents)
Lagomorpha (rabbits, hares, pikas)
PrimatomorphaDermoptera (colugos)
The names Colugidae, Galeopithecidae, and Galeopteridae are synonyms for Cynocephalidae. Colugo, Dermopterus, Galeolemur, Galeopithecus, Galeopus, and Pleuropterus are synonyms for Cynocephalus.
Claw of dead Malaysian colugo
Colugos (/kəˈluːɡoʊ/) are arboreal gliding mammals that are native to Southeast Asia. Their closest evolutionary relatives are primates. There are just two living species of colugos: the Sunda flying lemur (Galeopterus variegatus) and the Philippine flying lemur (Cynocephalus volans). These two species make up the entire family Cynocephalidae (/ˌsaɪnoʊˌsɛfəˈlaɪdi, -ˌkɛ-/) and order Dermoptera (not to be confused with Dermaptera, an order of insects known as earwigs).
Despite being called "flying lemurs", the colugos do not fly and are not lemurs, although related. Instead, they glide as they leap among trees. They are the most capable gliders of all gliding mammals. A fur-covered membrane, called a patagium, connects to the face, paws, and tail. This enables them to glide in the air for distances of up to 200 metres (660 ft) between trees. They are also known as cobegos.
