Following the trail of the elusive proboscis monkey in Borneo

Abstract

For decades, knowledge about the endangered proboscis monkey was gleaned from limited information about their behavior from boat surveys conducted along riverbanks, where the monkeys rest during the early morning and late afternoon. This was due to the dense and swampy habitats they live in, which made them nearly impossible to track once they moved into inland forests. By conducting full-day continuous observations on foot in riverine forests in Sabah, Borneo, Malaysia, alongside my colleagues, we produced pioneering research about this species. Conducted over a period of more than 15 years since 2005, our studies have resulted in the comprehensive collection of information about the proboscis monkey with regards to its feeding and ranging behaviors as well as novel findings about its fascinating digestive strategy of rumination and the unique functionality of its “odd-nose.”