Eco-ethology of Proboscis Monkey, Nasalis larvatus, and Assessment of its Role in Forest Regeneration along the Kinabatangan River


PhD researcher: Valentine Thiry
Institution: Université Libre de Bruxelles
Supervisors: Martine Vercauteren, Roseline C. Benudel-Jamar, Benoît Goossens
Duration: October 2014 – October 2018

Valentine was studying proboscis monkeys and their feeding ecology in particular. She made behavioural and ecological observations along the Kinabatangan riverside and collected faecal samples every morning at sleeping sites. She studied proboscis monkey’s diet using the DNA metabarcoding methodology by comparing short chloroplast DNA sequences found in faeces to a plant DNA Database (a database she built along the way for this purpose). Her aim was to identify proboscis monkey food items in the Kinabatangan fragmented landscape and to study the seasonal dietary variations throughout the year. Interested in the role proboscis monkeys could potentially play in seed dispersal, Valentine also investigated faecal samples for their seed content and set up different germination tests. Finally, she studied how the phytochemical composition of leaves varies between consumed and not-consumed plant species, with a gradient distance to the river.


The project aimed to determine which of the key plant species for N. larvatus are in the fragmented landscape of the Lower Kinabatangan Wildlife Sanctuary, and the findings were used to contribute to the conservation of this endangered species.

Proboscis Monkey ©Rudi Delvaux