Research Objective

Japanese macaques live in large multi-male, multi-female groups that chance in size and social structure over time. One social process that has a high impact on the social structure of the entire population is fission. Fission is the voluntary separation of a previously coherent social group into two independent groups and it occurs frequently within Japanese macaques. Fission has therefore been the focus of scientific research for a long time, which is why we know a lot about how the process of fission goes. What we do not know, however, is what exactly causes a fission. There is furthermore a lack of knowledge on what happens after fissions. It is expected that after the initial separation, the groups stay separated and individuals remain within their newly chosen group, but these expectations have not been tested yet. Our research aims at testing both the theories on the causation of fission as well as the expectations of what happens after the split. In order to do so, we analyse long-term behavioural data collected on the Affenberg population that underwent a fission in 2020. We furthermore keep collecting this type of data to assess the long-term aftermath of this highly dynamic social process.

Research Questions

What caused the fission at the Affenberg population?

How does a semi-free ranging population of Japanese macaques within the process of fission adapt to the inability to fully separate?

How does the social network of a post-fission population of Japanese macaques change over time?