Horsfield's tarsier (Cephalopachus bancanus), also known as the western tarsier, is a species of tarsier. It occurs on Borneo, Sumatra and nearby islands. It is the only member of the genus Cephalopachus.
Preferred habitat of Tarsius bancanus is primary and secondary forest, although it can also be found in mangroves and forest edges. It is a vertical clinger and leaper, and generally does not venture into more open areas unless both prey and small-diameter trees to cling to are present. It can also be found along the forest edge and in fruit plantations. Although it is generally described as a lowland species, residing below 100 m in elevation, sightings above 1200 m have been documented.
Range elevation: 0 to 1200 m.
Habitat Regions: tropical
Terrestrial Biomes: rainforest
Other Habitat Features: agricultural
The most striking feature of tarsiers is their large eyes, which are larger than those of any other mammal, with respect to body size. Tarsius bancanus is small. Males are 12 cm in length on average and range in mass from 122 to 134 g. This species is sexually dimorphic, as females are on average 10 grams lighter than males. Its fur is grey and/or brown and does not help distinguish it from the other tarsiers species. It has a very long tail, nearly twice as long as its head and body. The tale is scaly in appearance, with the exception of a tuft of hair near the distal end. In general, tarsiers have extraordinarily long hind legs (the longest legs of any mammal in proportion to body length), which contributes to their primary mode of locomotion as vertical clingers and leapers. The forelimbs are rather shorter. All four limbs end in long, thin digits, and the front digits have disc-like pads.
Range mass: 122 to 134 g.
Average length: 129 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger