The Behavioural Profile Of Pongo Pygmaeus Morio In Kutai National Park: Positional Behaviour In A Precarious Habitat

This study examined the positional behaviour of female Pongo pygmaeus morio individuals in Kutai National Park, East Kalimantan, Indonesia during the 2015-2016 El Niño cycle. Several positional behaviour studies have been conducted on the Sumatran orangutan (P. abelii), yet only one had been conducted on P. p morio; this study was conducted by Cant in 1982, during a similarly strong El Niño cycle, and also only sampled female individuals (1987a). As such, this study provided an opportunity to verify the behavioural profile of P. p. morio as found by Cant during a similar environmental year, as well as verify the interspecific comparisons drawn from his sole study 35 years ago. This study verified some of the previous interspecific findings – mainly that P. p. morio employs an elevated use of ‘ipsilateral suspend’. However, some divergences from previous findings were found – mainly that ‘brachiation and forelimb swing’ and ‘sway’ occurred at higher frequencies than previously found in P. p. morio. Lower levels of ‘vertical climb’ and ‘descent’ were also found in P. p. morio here than found in the previous P. p. morio study.