Hose's langur (Presbytis hosei) is a species of primate from Southeast Asia. It was first identified in Kutai National Park and Sangkulirang Peninsula, East Kalimantan, Indonesia, in 1985.
Hose's langurs have a light to dark gray coat. Their stomach and chest are white in color. The face of Hose's langurs is pink and has black markings. Their hands and feet are black.
Hose's langurs are found only on the island of Borneo, including Brunei, Kalimantan (Indonesia), and East Malaysia where they inhabit subtropical or tropical moist forests. They live both in lowland and hilly areas and may sometimes visit plantations.
Hose's langurs live in trees and are active during the day. They live in groups of 6-8 individuals. Each group consists of one adult male, 2 or more females, and their young. Hose's langurs are very territorial with males calling loudly when trying to keep intruders away.
Hose's langurs are mainly herbivores (folivores, frugivores, granivores) and eat seeds, young leaves, fruits, and flowers. However, they may sometimes take bird eggs and nestlings.
Hose’s langurs are polygynous, meaning one male mates with more than one female during the breeding season. Each female gives birth to one infant. Weaning usually occurs at the age of one year and young Hose's langurs become reproductively mature when they are 4-5 years old; at this age, young males leave their family groups.
In 1996, Hose's langurs of East Kalimantan, Indonesia, were among the most common primates in the area but in 2003, their population had decreased by 50-80%. The sudden drop in population arises from the rising demand for their bezoar stones and to prevent crop raiding and the rapid deforestation and removal of their native habitat. Hose's langurs continue to lose their habitat and every known area in which they live has been affected severely by humans.
The IUCN Red List and other sources don’t provide the number of the Hose's langur total population size. Currently, this species is classified as Vulnerable (VU) on the IUCN Red List, and its numbers today are decreasing.