Locomotor development and gap crossing behaviour in Bornean orangutans (Pongo pygmaeus)

[摘要] Orangutans are the largest predominantly arboreal primate and consequently have a diverse repertoire of positional behaviour. Problems associated with travel on thin flexible supports worsen as body size increases; therefore locomotion should vary with body size. The aim of this thesis was to explore how orangutans solve problems related to life in wild and captive environments and how this changes with growth and development. A cross-sectional sample of wild orangutans (Pongo pygmaeus wurmbii) was studied at Tuanan Field Station in Central Borneo with subjects ranging from infant to adult. Results from wild orangutans showed that locomotion varied according to body size with larger orangutans using larger supports and gaining stability by bearing their weight in suspension. In contrast captivity promoted higher frequencies of terrestrial behaviours and these increased with age. Wild orangutans crossed large gaps in the canopy by oscillating compliant trunks. However I found that these skills are not fully mastered until 6 years old. Mothers were found to provide assistance during gap crossing according to the needs of their offspring. This thesis has shown that complex locomotor behaviour develops slowly during ontogeny and this may have implications for orangutan life history in different types of habitat.

[发布机构] University:University of Birmingham;Department:School of Biosciences

[关键词] Q Science;QL Zoology