After studying biology and anthropology at Munich University, I have been affiliated with the Indian Institute of Science (Bangalore) and several institutions of the Max-Planck-Society. Together with my wife, Barbara Fruth, who is reader at the John Moores University of Liverpool, I am directing field work at LuiKotale (DRC). My current research interest focuses on the following question: what are the environmental conditions under which bonobos have evolved and how do bonobos differ from their closest living relatives, the chimpanzee and from modern humans? What were the causes for the divergent evolution of bonobos and chimpanzees? Have males and females been affected differently by the divergent development and if so, what were the driving forces to induce changes in one but not the other sex? In order to tackle these questions, I am using information from wild bonobos observed at Lomako (1989-1998) and LuiKotale (since 2002). Current projects aim at developmental processes in bonobos and chimpanzees. Integrating data on developmental changes in physiology, behavior and morphology is one way to explore the emergence of differences in social behavior that are so prominent in adult individuals. I am convinced that it needs information from the two sister-species (bonobo and chimps) to model the evolutionary history of our own species. Understanding the driving forces that led to their divergent evolution will help us resolving the exciting question of why we became a species that combines such opposite characteristics such as empathy, cooperation and food provisioning, the strategic use of non-reproductive sex, and merciless aggression.