Time budget of daily activity of silvery lutung (Trachypithecus cristatus) in coastal forest habitat at Gunung Padang, West Sumatra

Abstract

Primate’s time budgets are the important aspect to investigate their ecological influences in their habitat. This study collected data on daily activities in a group of silvery lutung (Trachypithecus cristatus) in coastal forest habitat at Gunung Padang, West Sumatra, Indonesia from August 2018 – July 2019, using instantaneous scan sampling method with 10-min intervals. This study analyzed the activity of wild silvery lutungs in study site, with emphasis on the age-sex differences and montly changes in their activity budget. This group spent most of time resting in their daily activity (average 47.50% of the total daytime resting), then followed by moving, feeding, grooming and other activities (conflict, nursing, urinating-defecating, playing, etc.). Resting peaked simultaneously in the morning and peaked back in the afternoon while moving and feeding decreased in this period. Their time budgets showed significant monthly variation: they spent a higher value of time feeding from September - Oktober 2018. They also differed among different sex-age classes: nursing females spent more time for actively moving, whereas adult male and single females devoted more time to resting, feeding, and grooming. These differences in their time budgets may reflect fundamental differences in reproductive biology, parental investment and development among the different age-sex classes.