The Sunda flying lemur or Sunda colugo (Kubong) is one of the species from the family Cynocephalidae (Colugos). This species usually has grey fur with extensive black-and-white markings, but some individuals have tinged reddish-brown or reddish-brown fur with light buff or orange markings (Francis, 2019). The fur colour blends in with the tree trunks and environment, making it exceptionally well camouflaged to stay hidden from predators such as Changeable hawk-eagle (Lim, 2007; Dzulhelmi, 2013). The adult Sunda colugo has about 33-42 cm head-body length and weighed around 0.925-1.7 kg (Francis, 2019). It has large eyes with excellent night vision, small ears and a pointed snout. Their legs are relatively long and equipped with long, sharp claws on toes that help them grip the tree trunks or branches.

Besides that, the Sunda colugo is an accomplished glider with a more extensive gliding membrane than the flying squirrels (Panyitina et al., 2015). The fur-covered gliding membrane called patagium extends from its neck to fingertips, stretching along both sides of the body to hind toes and enclosing its tail (Panyitina et al., 2015; Francis, 2019). This animal initiates glide at high velocities for about 10 ms^-1 with a leaping range of around 5 m and travels at an extensive distance of approximately 145 m (Dzulhelmi, 2013). This, in turn, reduces travel time searching for good food sources and increases locomotion efficiency to escape threats or predators if encountered (Dzulhelmi, 2013).

Generally, the Sunda colugo can be found throughout Southeast Asia, ranging from southern Myanmar, southern Thailand, Laos, Vietnam, Cambodia, Peninsular Malaysia, Singapore, Sumatra, Java, Borneo, Bali and many smaller Indonesian islands (Corbet & Hill, 1992; Ruggeri & Etterson, 1998; Stafford, 2005; Francis, 2019). Colugo populations from Peninsular Malaysia, Borneo and Sumatra are genetically and morphologically different (Jane?ka et al., 2008; Mason et al., 2016). Therefore, researchers have suggested that colugos may include four to eight other species (Jane?ka et al., 2008; Mason et al., 2016). In Malaysia, the Sunda colugo can be found in 27 (Peninsular Malaysia), 11 (Sabah) and 34 (Sarawak) locations from various states and divisions (Dzulhelmi & Abdullah, 2010). It can be found in primary and secondary forests from lowland to upland forests, mountainous areas, mangroves forest, peat swamp forest, tree plantations (e.g. rubber and coconut plantations), orchards (e.g. old durian fruit orchard) and gardens (Lim, 1967; Hill, 1993; Yasuma & Andau, 2000; Feldhamer et al., 2003; Ketol et al., 2006; Abdullah et al., 2010; Francis, 2019).

This strictly arboreal mammal is mainly nocturnal. During the day, the Sunda colugo roost primarily on the tree trunks or tree holes, generally high up, but sometimes can be found to roost as close to the forest ground (about 1.5 m) on the tree trunks (Dzulhelmi, 2013). This animal is usually seen in an upright posture on a tree trunk or hanging in an inverted pose beneath tree branches (Dzulhelmi, 2013). At dusk, it becomes active, mainly foraging in tree canopies and at the end of branches to feed (Dzulhelmi, 2013). It feeds primarily on leaves, especially the young leaves, and additionally on flowers, buds, shoots, sap and fruits such as rambai fruits (Baccaurea motleyana) (Lim, 2007; Ketol et al., 2006; Dzulhelmi & Abdullah, 2009). Occasionally, it also feeds on ants (Dzulhelmi & Abdullah, 2009). Due to its diets, this species may play an essential role in seed dispersal and flower pollination (Burnie & Wilson, 2001).

Moreover, the Sunda colugo is usually found solitary either during the day or night (Dzulhelmi, 2013). Despite that, this animal does live with several other individuals within the same area, forming a set of social structure that consists of one male with few females (about 2-4 individuals) and infants (about 1-2 individuals in any) (Dzulhelmi, 2013). The female often carries a single young which clings underneath its body. Besides, the Sunda colugo also communicates with each other (Dzulhelmi, 2013). Apart from audible calls, this species also uses ultrasound to communicate with each other and avoid predators' detection (Miard et al., 2018). Colugos are believed one of the hosts for lentiviruses that may cause chronic diseases such as acquired immunodeficiency syndrome (AIDS) (Hron et al., 2014).

The Sunda colugo is categorized as the least concern (LC) by the IUCN Red List of Threatened Species (Boeadi & Steinmetz, 2008). This species is also classified as a totally protected species by the Malaysian Wildlife Conservation Act (WCA) 2010. However, this species' population is threatened by the rapid loss of forested habitat (Boeadi & Steinmetz, 2008). Therefore, it is crucial to protect this precious animal and its habitats and appreciate its roles in sustaining our natural environments.