Northern Pig-tailed Macaque (Macaca leonina)

Macaca nemestrina is a medium sized primate with light brown fur, which is found in a portion of Southeast Asia from southern Thailand to the island of Borneo. This primate is deemed chiefly terrestrial, but also exhibits arboreal traits. Its habitat is threatened by expansion of oil palm plantations which have been created in prior lowland rainforests; slash and burn practices, especially in Indonesian Borneo have also destroyed and fragmented considerable habitat area. Colouration is a light brown, with even lighter undersides, the tail and elongated muzzle being nearly hairless (Cawthon Lang. 2009) The common name is associated with the trait of this primate's tail held in a semi-erect fashion, much like the nature of a pig's tail.

M. nemestrina occurs in Malaysia (including the Malay Peninsula and Sabah and Sarawak Borneo), Indonesia (Bangka, Kalimantan Borneo and Sumatra), Brunei as well as southern peninsular Thailand. There are also small populations of M. nemestrina on Singapore Island as well as the Natuna Islands. (Groves. 2001) M. nemestrina is known to hybridize with its close relative M. leonine in southern peninsular Thailand and on the islands of Yao Yai and Phuket. (Groves. 2001) Unlike most primates in the region, the Sunda pig tailed macaque is almost evenly distributed among montane and lowland rainforests. (World Wildlife Fund & Hogan. 2011)

M. nemestrina is found in lowland and montane rainforests from sea level up to elevation at least 2000 metres. Troops often occur in swamp forests, riparian zones and coastal zones. M. nemestrina is considered a primate that is diurnally active, being chiefly a frugivore in food consumption; however, insects, aquatic crustaceans and leafy materials are also eaten. (Laska. 2001) Lifespan in the wild is on the order of three decades. The species is considered polygynandrous, with mating occurring virtually throughout the year. A female typically gives birth to a single infant subsequent to a gestation interval ranging from 23 to 26 weeks. The offspring are nursed for a period of 35 to 52 weeks. After weaning, M. nemestrina is considered to be an adolescent, until attaining reproductive maturity at the age of around three years old for females and four and one half years for males.

M. nemestrina is classified as Vulnerable by the IUCN under Red List criterion A2cd ver 3.1. (Richardson et al. 2008) The principal threat to this species has been the human population explosion in the lowland rainforests of Indonesia and Malaysia, along with concomitant habitat destruction for creation of oil palm plantations in this region. In addition to habitat loss, the species has been systematically persecuted by farmers, who consider this primate as a cause for certain crop predation. According to Richardson et al (2008) the total population of M. nemestrina has declined by approximately thirty percent since the early 1970s.