Tarsiers are small, nocturnal primates found in South East Asia. Several species are endemic to the island of Sulawesi including Tarsius pumilus, Tarsius spectrum and Tarsius dianae. They are found in primary and secondary rainforest.

Tarsiers are characterised by their large, round eyes, long feet and long tails. They are the smallest primates known, measuring between 11 and 15cm in length and weighing only about 120g. They have long hindlimbs which allows them to jump between trees and adhesive pads on their digits to facilitate climbing. Their diet consists entirely of insects, which is unusual for primates.

Spectral tarsiers (Tarsius Spectrum) exhibit a high degree of social behaviour in comparison to the Borneo and Phillipine tarsiers. They are known to sleep together in family groups. Spectral tarsiers also forage in groups, and although this decreases their insect capture rate due to increased competition among group members, there are thought to be several benefits. Living in a group may an advantage when predators are encountered, and 'mobbing' behaviour has been observed to ward of predators. Living in groups may also be an advantage when females are sexually receptive.

Unlike other nocturnal mammals, spectral tarsiers increase their foraging and social behaviour during bright moonlight; insects are abundant in moonlight, and thus more insects are captured. Because they are at greater risk from predators in bright moonlight, group foraging increases their vigilance.

Tarsiers exhibit unusual parental care behaviour. While foraging, they don't transport their young on their bodies, instead 'parking' them in a tree while they forage in it. The infant is then transported to another tree and parked while the mother forages in that tree. It is thought that this behaviour saves energy, as infants can weigh up to a third of an adults body weight.

Spectral tarsier

The IUCN classes tarsiers at lower risk to extinction. Tarsiers are relatively abundant in protected areas in Sulawesi such as Tangkoko Dua Saudara Nature Reserve. However, Tarsiers have a limited geographic range, and little is known about their current distribution throughout Sulawesi. Habitat disturbance is occurring throughout much of their known range, and hence it has been suggested that their conservation status is changed to vulnerable.