Dusky Leaf Monkeys are arboreal and are distributed across the Malay Peninsulain southern Myanmar and some parts of Thailand. The natural range of these primates also include the islands of Langkawi, Penang, and Perhentian Besar.
These social animals, travelling in groups of 5 – 20, typically consist of one or more mature males as well as two or more mature females. Mature males of these groups spend their time keeping watch for potential predators, holding the group united and patrolling the home range of the community. As diurnal animals, these monkeys are active during the daytime hours.
During most of their active time, the primates remain in the tree canopy, at heights of over 35 meters. When travelling between trees, they climb, leap, and walk along tree branches, using all of their four legs. With nightfall, the. Dusky Leaf Monkeys move to their roosts, located in the trees. Their communication system includes a complex system of vocalizations. The group communicated with each other using snorts, hoots, murmurs and squeaks
Dusky Leaf Monkeys are herbivores that generally feed upon young leaves, fruits, shoots, and seedlings.
They have a polygynous mating system where the males compete for their mating rights. As a general rule, the largest, strongest and most aggressive male will breed with the females. Breeding occurs periodically during the year with a gestation period of about 145 days, yielding a single young. Females produce o !spring at intervals of two years, typically in JanuaryMarch, although some may give birth in the summer months.
During the first 20 days after birth, the infant is almost constantly with its mother. At around one year old, the baby begins climbing, venturing away from its mother, and taking solid food. Individuals of both sexes reach sexual maturity at 3 – 4 years old. Dusky Leaf Monkeys are born with a very distinct coat, typically orange or bright yellow. During the first six months of their lives, this vivid color pattern gradually turns to grey.
Dusky Leaf Monkeys are currently hunted for their meat throughout their range. These animals also su !er from loss and degradation of their natural range because of urbanization, agriculture as well expansion of oil palm plantations. Additionally, population in Peninsular Malaysia is threatened by a high level of roadkill.
The IUCN Red List and other sources don’t provide the exact statistics of the Dusky Leaf Monkeys’ total population. This species’ numbers are on a steady decline, and the animals are classified as Near Threatened on the IUCN Red List.
