Sexual Behaviour of the Spectral Tarsier (Tarsius spectrum) in Captivity.

Tarsius spectrum is a primate species endemic to Sulawesi. Populations of the species have decreased due to habitat destruction and hunting. The sexual behaviour of T. bancanus and T. syrichta are known, but that of T. spectrum has not been reported until recently. The aim of this research was to study the sexual behaviour of T. spectrum in captivity. We observed 3 pairs of T. spectrum at the captive breeding facility of the IPB Primate Research Centre for 9 months using focal animal sampling. We showed that principal courtship behaviours were scent marking (36.7%) and genital marking for females (16.2%) and genital inspection for males (16.0%). Copulations lasted between 3 and 4 min, starting with the male mounting the female and thrusting quickly as many as 168-236 times followed by slow thrusting 9-20 times. When slow thrusting occurred, females vocalized up to 6 times. At the end of the copulation sequence, males remained motionless with their penis inserted within the female's genitalia for about 31 s. Copulation occurred only once for each pair during the observation period. Our results should be useful to support breeding programmes and conservation actions for tarsiers.