Taxonomy
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Mammal
- Order
- Primates
- Family
- Cercopithecidae
- Genus
- Presbytis
Habitat
Thomas' langurs primarily inhabit lowland and hill forests in northern Sumatra, Indonesia, at elevations up to 1,500 meters. They prefer dense tropical rainforests with abundant tree cover for foraging and shelter, avoiding open areas due to their arboreal lifestyle.
Diet
Thomas' langurs mainly eat leaves, young shoots, and fruits from various forest trees, with a preference for foliage from species like figs and lianas. They are folivorous primates that feed primarily during the day, spending several hours foraging in the canopy to meet their dietary needs. Occasionally, they supplement their diet with flowers, buds, and insects.
Behavior
Thomas' langurs live in social groups of 5-15 individuals, typically led by a dominant male, and exhibit strong territorial behaviors including vocalizations and chases to defend their range. They are diurnal and highly arboreal, spending most of their time in trees where they move quadrupedally or leap between branches. These monkeys communicate through a variety of calls and facial expressions, and they often rest in groups during the hottest parts of the day.
Conservation Status
Thomas' langurs are classified as Endangered by the IUCN due to habitat loss from deforestation and agriculture. Population trends show a continuing decline, with major threats including logging and human encroachment in their Sumatran range.