A study was published several days ago in the journal Proceedings of the Royal Society B examining the social relationships among 13 mountain gorilla groups in Rwadna over 12 years. Typically, mountain gorillas have social groups of 12 to 20 individuals. A group of this size often yields the most diversity in relationships.
Sometimes, mountain gorilla groups can become as large as 65 individuals. This study looked at what happens across time when gorilla groups increase five fold. The team specifically characterized seven relationships between gorillas, the relationship categories ranged from mother and child to decidedly weaker links. As these groups expanded, relationships strained and became more distant across the categories they looked at. Close ties became fewer. This observation challenges the existing idea that large groups equal more complex social networks.
The study was led by Robin Morrison, who is a postdoctoral researcher at the Dian Fossey Gorilla Fund identified that a similar pattern occurs in human social groups. She hypothesizes that happens because the time and investment gorillas and humans need to put into maintaining strong relationships might strain the group size. The findings outline the complexity of gorilla social groups.