Robin Morrison

The University of Zurich · Department of Evolutionary Anthropology

The study of western gorilla social behaviour has primarily focused on family groups, with research on inter-group interactions usually limited to the interactions of a small number of habituated groups or those taking place in a single location. Key reasons for this are the high investment of time and money required to habituate and monitor many g...

Social complexity reflects the intricate patterns of social interactions in societies. Understanding social complexity is fundamental for studying the evolution of diverse social systems and the cognitive innovations used to cope with the demands of social life. Social complexity has been predominantly quantified by social unit size, but newer meas...

Many species show territoriality, in which territory owners have exclusive or priority use of a region. In humans, tolerance of others within our space also depends greatly on our social relationships with them. This has been hypothesized as one potential driver of the evolution of long‐term, inter‐group relationships, through enabling shared acces...

Mothers are crucial for mammals’ survival before nutritional independence, but many social mammals reside with their mothers long after. In these species the social adversity caused by maternal loss later in life can dramatically reduce fitness. However, in some human populations these negative consequences can be overcome by care from other group...

Minimizing disease transmission between humans and wild apes and controlling outbreaks in ape populations is vital to both ape conservation and human health, but information on the transmission of real infections in wild populations is rare. We analyzed respiratory outbreaks in a subpopulation of wild mountain gorillas ( Gorilla beringei beringei )...

Variation in mating systems and in individuals’ copulation patterns can have important consequences for the genetic structure of a population and ultimately its evolution. Whilst most gorilla sub-species form single-male, polygynous reproductive groups, mountain gorillas have both single-male and multimale reproductive groups. Considerable research...

Extensive research across fields has repeatedly confirmed that early-life adversity (ELA) is a major selective force for many taxa, in part via its ties to adult health and longevity.1,2,3 Negative effects of ELA on adult outcomes have been documented in a wide range of species, from fish to birds to humans.4 We used 55 years of long-term data coll...

Whilst the conservation impacts of density‐dependent population effects have been well studied, the impact that socially‐driven changes (e.g. group fissions that increase group density) can have on population growth in social species have only recently come to light. An increase in group density and intergroup encounters in a subpopulation of mount...

Supplementary tables for: Social groups buffer maternal loss in mountain gorillas

Mothers are crucial for mammals' survival before nutritional independence, but many social mammals reside with their mothers long after. In these species the social adversity caused by maternal loss later in life can dramatically reduce fitness. However, in some human populations these negative consequences appear to be overcome by care from other...

The evolutionary origins of how modern humans share and use space are often modelled on the territorial-based violence of chimpanzees, with limited comparison to other apes. Gorillas are widely assumed to be non-territorial due to their large home ranges, extensive range overlap, and limited inter-group aggression. Using large-scale camera trapping...

Modern human societies show hierarchical social modularity (HSM) in which lower-order social units like nuclear families are nested inside increasingly larger units. It has been argued that this HSM evolved independently and after the chimpanzee-human split due to greater recognition of, and bonding between, dispersed kin. We used network modularit...