Project Status: Ongoing

Immigrant orangutan males as cultural vectors & the evolution of tolerance vs. xenophobia

Throughout human history immigrants have always been drivers of cultural change, contributing to the diversity and formation of local cultures by transmitting new knowledge and skills. Nevertheless, xenophobic tendencies that prevent beneficial mutual exchange are on the rise. There is evidence that both tendencies, being tolerant as well as being xenophobe toward strangers, are as... Read more »

Nutritional ecology of the Sumatran orangutan at Suaq Balimbing

In the frame of this project, we aim to compare caloric intakes and nutrient compositions of the diets of different age-sex classes. For this, we collect and analyze the fruits and other food items in the diet of the orangutans at Suaq. We further want to investigate how these factors develop in immatures as a... Read more »

Multimodal communication in orangutans: redundancy versus complementarity

Language is commonly narrowed down to speech, but human face-to-face communication is in fact an intrinsically multimodal phenomenon. Despite growing evidence that the communication of nonhuman primates, our main models for language evolution, is also inherently multimodal, most studies have focused on either gestures or vocalizations in isolation.   This project aims to address this... Read more »

Male-female relationships – from friendship to coercion

Orangutans are a ‘semi-solitary’ species, with a fission-fusion based social organization. The degree of sociability is tightly linked to their ecology. Yet, their social system is still not fully understood and there is evidence for differences between the two species, Pongo abelii and Pongo pygmaeus. This study aims at investigating and comparing male-female social interactions... Read more »

The development of cognition and curiosity in immature orangutans

The cultural intelligence hypothesis states that individuals with more opportunities for social learning during ontogeny will later show a wider repertoire of learned skills as well as enhanced problem solving skills. Furthermore, from an ultimate point of view species with more opportunities for social learning are predicted to show an innate predisposition to be more... Read more »