White-Fronted Langur (Presbytis frontata)
Monkeys in Borneo are represented by two distinct groups: the langurs or leaf monkeys and the Proboscis Monkey (subfamily Colobinae) and the macaques (subfamily Cercopithecinae). The colobines are mainly arboreal, have a long tail, lack cheek pouches and have a large, sacculated stomach which permits breakdown of leafy material into digestible substances and helps detoxify poisonous leaves. The macaques are partly terrestrial, with a short or long tail, cheek pouches for temporary storage of food and a simple stomach capable of breaking down only a limited amount of leafy material.
Measurements: HB 470-540, T 630-740, HF 165-180 (3 Sarawak and Kalimantan specimens).
Identification: Mainly grey-brown, with a distinct bare white spot on the forehead. P.f. frontata: brownish, with darker arms, legs, top and sides of head and tail; chin and lower cheeks greyish. The white spot on the forehead is roughly triangular in shape . P.f. nudifrons: dark greyish, with blackish hands, feet and base of tail; underparts and distal ends of tail paler grey-brown; throat white. The white spot on the forehead is rather square and divided by a vertical line of short black hairs.
Ecology and Habitat: Diurnal. Ecology unknown but probably similar to the Maroon and Hose's Langurs, P. rubicunda and P. hosei. Occurs in tall lowland and hill dipterocarp forests.
Distribution: Restricted to Borneo south of about 3o North. P.f. nudifrons: recorded from central Sarawak between the upper S. Rajang and upper Batang Lupar, including Lanjak-Entimau Wildlife Sanctuary.