Presbytis

Presbytis is a genus of Old World monkeys in the family Cercopithecidae, within the subfamily Colobinae and the tribe Presbytini. Members of Presbytis are commonly known as leaf monkeys or surilis and are native to Asia. The genus has included several species distributed across Southeast Asia, with ranges extending through the Malay Peninsula, Sumatra, Borneo, Java, and parts of Indochina and southern China.

Physically, Presbytis individuals tend to have slender bodies, long tails, and fur colors that range from gray to brown, often with distinctive facial markings or patterns in different species. They exhibit colobine adaptations, including a complex, multi-chambered stomach that enables digestion of fibrous leaves. They have the typical primate dental formula of 2.1.2.3 and rely on arboreal locomotion. Behaviorally, they are primarily diurnal and live in social groups that vary in size and composition, feeding largely on leaves with fruit and seeds consumed opportunistically.

Ecology and distribution: Presbytis species are found in tropical forests and woodlands across parts of Southeast Asia. They occupy a variety of forest habitats, from lowland to montane regions, and play a role in seed dispersal and forest dynamics. Their diets and activity patterns are influenced by seasonal fruiting and leaf availability.

Taxonomic notes: The genus Presbytis has undergone extensive revision as molecular studies clarified relationships within the Presbytini. A number of species formerly placed in Presbytis have been reassigned to other genera, notably Trachypithecus and Semnopithecus. As a result, the genus today comprises a smaller group of species, with related species distributed among neighboring genera.

Conservation: Habitat loss, fragmentation, and hunting threaten many Presbytis populations. Several species are considered threatened or endangered, and ongoing conservation efforts emphasize habitat protection, legal protections, and the maintenance of ecological corridors to support viable populations.