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Daily Activity and Home Range Use of Crested Macaques (Macaca nigra) in the Tangkoko Nature Reserve, North Sulawesi

Giyarto, Dyah Perwitasari-Farajallah, Saroyo, Dr. Antje Engelhardt, Macaca Nigra Project, DPZ-IPB-UNSRAT - 2010 completed

The seven macaques endemic to the island of Sulawesi are important for our understanding of primate evolution. One of these macaques, the crested macaque (Macaca nigra), is nowadays critically endangered due to poaching and loss of habitat and may go extinct within this century. Unfortunately, we still know little about its ecology, reproductive biology and social behavior, information that is important for successful conservation of a species.

We therefore carried out a study on two neighbouring, habituated groups (R1 and R2) living in the Tangkoko Nature Reserve from July 2006 until June 2007. We collected behavioural data using instantaneous scan sampling every 30 minutes for 5 minutes collecting data on three adult males, three adult females and three juveniles. In addition. we carried out focal animal sampling on adult males and adult females during ovarian cycles using instantaneous sampling (interval: one minute). In addition, we made random plots 10 X 10 meters for habitat vegetation analysis and 20 X 20 meters for habitat profile. Altogether, 5075.5 hours of behavioural data were collected for both groups.

Both groups spent most of their time feeding and foraging (R1: 54.11%; R2: 42.26%) followed by either resting (R1: 16.9%; R2: 22.51%) or socializing (R1: 16.14%; R2: 22.91%). The remaining time was spent moving (R1: 12.41; R2: 0.15%) and drinking (R1: 0.4%; R2: 0.2%). The majority of food consisted of fruits (60%). Both groups spent most of their activities on the ground (60%). Whereas R1 spent most of their time in the primary forest, R2 roamed more often in the secondary forest. Possibly as a consequence and although they moved less often compared to R1, their home-range was double the size of that of R1.