The Ecology and behaviour of the proboscis monkey (nasalis larvatus) in the lower Kinabatangan, Sabah

dc.contributor.authorBoonratana, Ramesh
dc.date.accessioned2023-01-06T03:36:10Z
dc.date.available2023-01-06T03:36:10Z
dc.date.issued1993
dc.description.abstractNasalis larvatus is a large, sexually dimorphic, monotypic arboreal colobine, endemic to the island.of Borneo, where it is largely restricted to riverine, peat swamp and mangrove forests of the coastal lowlands. The aims of the study were to assess the ecology and behaviour of N. larvatus in relation to the botany and phytochemistry of the habitat flora. This involved two years field work in the mangrove and riverine forests in the Lower Kinabatangan area. The basic social unit of N. larvatus is a relatively stable harem, comprising a single adult male, several adult females and their offspring. The social structure of N. larvatus in the Lower Kinabatangan is flexible, and comprised relatively stable harem, all-male and predominantly male non-breed~ng groups. Different groups frequently selected riverside sleeping sites that were close to one another. Some groups associated more than others, implying a secondary level of social organisation, the band. Intra-group agonistic and social interactions were rare, implying that intra-group competition was low. This, in turn suggested that food was abundant and available. All colobines, including N. larvatus, possess specialised digestive physiology and sacculated stomachs with anaerobic, cellulolytic bacteria in their fore-stomachs. This adaptation allows them to break down cell wall constituents and defensive chemicals found in plant foods. N. larvatus· is a folivore-frugivore, with a strong preference for seeds. They are highly selective feeders, avoiding items with high levels of digestion inhibitors. Nasalis larvatus groups in the Lower Kinabatangan were wide-ranging, returning to sleep by the Kinabatangan River or its tributaries every evening. N. larvatus are not territorial, and the ranges of different groups completely overlapped each other. The horne range size of the focal harem group, SUI, at Sukau was observed to be 221 ha. SUl increased its day range lengths as high quality foods become scarcer, and the group selected particular quadrats on days when its members ate high quality foods. This suggested that food resources were unevenly distributed and highly clumped. Differences in horne range size, group size, population density of N. larvatus between sites, and the fact that groups were non-territorial, with completely overlapping ranges and low level of intra-group interactions, strongly implied that these variables were influenced by ecological pressures, particularly by the distribution, size and abundance of food resources.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/17085
dc.language.isoenen_US
dc.subjectProboscis monkeyen_US
dc.subject(Nasalis larvatus)en_US
dc.subjectLower Kinabatangan, Sabahen_US
dc.titleThe Ecology and behaviour of the proboscis monkey (nasalis larvatus) in the lower Kinabatangan, Sabahen_US
dc.typeThesisen_US
Files
License bundle
Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description: