2.2.2 Habitat and Distribution
Proboscis monkey have a very limited distribution (Bennett, 1986). N. larvatus depend strongly on forest adjoining waterways and sleep next to rivers or other watercourses every night (Macdonald, 1982). The species is scattered throughout Borneo from the mangroves and small islands in the coastal deltas, along all major rivers to numerous inland sites (Meijard & Nijman, 2000). They depend a lot on mangroves forest for food and cover (Kawabe & Mano, 1972). N. larvatus does not occur at high altitudes (Meijard & Nijman, 2000). According to Bennett and Gombek’s (1993) map showed that the species largely restricted to coastal and nearby swamp forest. Small populations are found much further inland next to major river (Mackinnon, 1986), and there are less frequent reports they were passing through hill forest areas (Bennett, 1986). 2.2.3 Social Behaviour There are two type of social system of N. …show more content…
larvatus which are one-male unit (OMU) and all-male unit (AMU). OMU consisting of one adult male, several adult females and their young while AMU consisting only young males (Murai, 2004). According to Boonratana (2000), some units actively associated with each other and they also can create multilevel society which specific units according to their sleeping sites within two separate bands (Yeager, 1991). Besides, the basic social unit of N. larvatus is a harem group which stable over time. Different groups frequently joined together, next to the river at night. Although the members of one harem remained together, the different groups were contiguous (Bennet & Sebastian, 1988). Groups of N. larvatus frequently met during day and also evening. The pattern of their movement which the groups move independently away from river in morning and travelled independently through forest. They met before the other groups moved away (Bennet & Sebastian, 1988). 2.2.4 Feeding Behaviour Proboscis monkey showed variation in percentage of time spent feeding, resting and travelling in relation to different categories of height of tress (Boonratana, 2000). Groups usually sleep in one or several nearby tress (Yeager, 1990) and feeding peaks were in the morning and at dusk (Boonratana, 1993). They engage more in resting than feeding and moving when availability of fruit is scarce (Matsuda et al., 2009). Their foraging activity depends on weather, if it was raining and cold they were normally not