The pygmy slow loris (Nycticebus pygmaeus) is a primate that can be found in Laos, eastern areas of Cambodia, the Yunnan Province, and in areas east of Mekong River in Vietnam. It prefers to reside in secondary, semi-evergreen, and mixed deciduous forests. This species was formally described in 1907 by J. Lewis Bonhote and was classified as one species with all loris species, although there are now nine distinct species.
The pygmy slow loris reaches an average body length between 7.7 and 9.1 inches, with a weight between 13 and 30 ounces. Although there are no significant differences between the sizes of males and females, all adult individuals vary in weight seasonally, most likely gaining weight in order to survive harsh winters. The fur on its upper body and back are red to reddish brown in color, with a black stripe extending down the back, while the underbelly is greyish-black with yellowish-orange markings. The stripe on the back, and the silver hairs that are sometimes present, can be absent, leading some to believe that seasonal variations in color can occur or that these markings may represent a separate species. The sides of the face and head are reddish in color and a white stripe extends down its nose from its forehead. The dark circles that occur around its eyes fade as it grows older.
Wild pygmy slow lorises are typically found in groups of two to four individuals and are active during the nighttime hours. Males hold territories that they will defend and they are known to scent mark over the scent of other males. This species communicates using many vocalizations including short whistles that are used by mothers and young and loud whistles that are used by females to attract a mate. Like all loris species, it will rub a toxic secretion from a gland near its elbow onto its fur, which is used to deter predators.
In captivity, females are able to breed for four to five days between the months of June and October and they are known to be slightly violent towards potential mates. After breeding, females can be pregnant between 184 and 200 days, after which time they will give birth to one or two young. Weaning occurs at about twenty-four weeks of age and sexual maturity is thought to be reached at sixteen to eighteen months of age.
Like other slow lorises, the pygmy slow loris is an omnivore, feeding on insects and fruit, among other food types. It prefers to consume plant materials like gum, which is readily available within its range. Its diet does depend on seasonal changes and it has been observed barely moving during the winter months in order to conserve energy. This species is thought to live for up to twenty years.
The pygmy slow loris is threatened by habitat loss in all areas of its range. Because of political issues in its range and its nocturnal lifestyle, information regarding its population numbers is limited and highly variable. This species is also threatened by hunting and the illegal wildlife trade, which has increased in many areas due to urban growth and economic fluctuations. This species has already experienced local extinctions in some areas of its range and is expected to undergo more extinction in the future. This species does occur in protected areas and has its own Species Survival Plan, which includes a successful captive breeding program. The pygmy slow loris appear in Appendix I of CITES and on the IUCN Red List with a conservation status of “Vulnerable.”
Image Caption: A Pygmy Slow Loris (Nycticebus pygmaeus) at the Duke Lemur Center in Durham, North Carolina. Credit: David Haring/Wikipedia (CC BY-SA 3.0)