The Stump-tailed Macaque or Bear Macaque (Macaca arctoides) locally known as Beruk Kentoi in Malay is an Old-World Monkey native to Cambodia, southwestern China, northeastern India, Laos, Malaysia, Thailand, Myanmar, and Vietnam (Chetry et al., 2020). In Malaysia, this species is particularly known to inhabit the state of Perlis which is located in the northern region of Peninsular Malaysia (Syamil et al., 2019; Roos et al., 2014). The only protected area in Peninsular Malaysia where this species can be found is Wang Kelian in Perlis State Park (Jayaraj et al., 2013). This macaque can be found in the broadleaf evergreen forest of tropical and subtropical regions where it inhabits high areas up to 2,000 m in primary or secondary forest (Cawthon-Lang, 2005; Francis & Barrett, 2008).

Macaca arctoides has some special features that distinguish it from other Macaca species. The babies are born with white hair, and becomes darker as they grow older. This species has long, thick dark brown fur that cover their bodies, except for the tail and face. Its tail is shorter than other species of the genus Macaca, measuring between 32 to 69 mm long. Its face is bright pink or red which becomes darken to brown or almost black as this spesies get older and are exposed to sunlight (Cawthon-Lang, 2005). What is special about Beruk Kentoi is that as they grow older, this macaque species will experience hair loss to become partially bald which starts at the forehead and advance towards the middle of their head. This process is similar to the process of hair loss that occurs in males for humans, but the process experienced by this macaque is happening to both sexes, male and female species (Uno et al., 1967).