Bioacoustics of Macaca nemestrina

Activity patterns. Sunda Pig-tailed Macaques appear to spend more time traveling, and on the ground, than foraging and feeding. They flee quietly on the ground when disturbed. During a 14month survey in Sumatra, 36 contacts were made while the macaques were traveling (38:9%) or fleeing (25%) compared with feeding (5-6%) or sitting (11-1%). In another study in Eastern Kalimantan, traveling or foraging on the ground accounted for 67% of contacts. An adjusted daily activity budget of locomotion (61%), resting (19%), foraging (16%), and social behavior (4%) was recorded during an 18month study in tropical rainforest in Peninsular Malaysia. In north Sumatran forests, Sunda Pig-tailed Macaques generally forage in small, widely dispersed subgroups that travel on the ground and seldom remain in the same place for long; they search for miscellaneous food items on the ground but more often feed in trees. Contact is maintained with a low vocalization audible at distances of 30-80 m. A common pattern appears to be sleeping in broad-crowned emergents at the fringe of primary forest and entering secondary or degraded forest to raid cropland. Sunda Pig-tailed Macaques may vocalize as they approach sleeping trees at dusk. At other times, they can be so silent that they are difficult to observe.