The silver leaf monkey (Trachypithecus cristatus), also called the silvered langur, is among the most frequently spotted mammals at Bako. Its silver-tipped fur gives the species a metallic shimmer in morning light, and the newborns are a striking deep orange — one of nature's stranger colour inversions. A troop of 15–20 individuals lives permanently around the park headquarters at Telok Assam.
Silver leaf monkeys are strict folivores, meaning their diet is almost entirely young leaves. Like the proboscis monkey, they have a multi-chambered stomach that ferments cellulose and detoxifies plant chemicals. You will often see them high in the canopy plucking tender new leaves rather than ripe fruit. Their slow metabolic rate means they spend long periods resting — look for groups sitting motionless in upper canopy branches from mid-morning to early afternoon.
Around the headquarters chalets and canteen area, the monkeys have become habituated to humans, making close observation easy. They are bold but not aggressive — unlike the long-tailed macaques, they rarely steal food from tables. Watch for the troop filing single-file across the roof of the park reception building each morning, a well-worn route they have used for decades. The Lintang Trail passes through their core territory; early morning walkers are almost guaranteed a sighting.
Infant silver leaf monkeys are born with bright orange fur that transitions to grey within three months. Multiple females in a troop will nurse and carry each other's young — a behaviour called allomothering that increases infant survival. If you see a small orange bundle clinging to a grey adult, that is likely a young one from the current breeding season. Bako's resident population is stable, and the species is listed as Vulnerable on the IUCN Red List — far better than the critically threatened tarsier, but still at risk from regional habitat loss.