Inkumbuza and Twibuke have always lived together and have a strong relationship. They were both born in the former Shinda’s group, which split after the death of dominant Shinda, their father. Twibuke, now 26, has been in charge of this group for about nine years and has done a great job ensuring the group’s stability in terms of composition and range. 

In fact, the group still uses the area that was historically used by Shinda’s group, on the slopes of Mount Bisoke, which is not often visited by other groups. That means interactions with other groups are infrequent, though they do occur sometimes. For example, there was a recent interaction with Segasira’s group, and both Twibuke and Inkumbuza seemed intimidated by silverback Segasira. After a few hours of loud screaming, displays and physical fights, Twibuke decided to move away but Inkumbuza was determined to keep facing the opponent. 

To protect the group, Twibuke had to forcibly drag Inkumbuza away, which involved biting him. This incident showed Twibuke’s mature leadership in minimizing risks, while Inkumbuza wanted to continue to challenge the opponent despite the consequences. It was interesting to see Twibuke teaching his younger brother a hard lesson.

It is normal in gorilla families to observe conflicts among males. While most are just occasional, some may lead to dominance challenges or to one male leaving the group. Ntambara’s group provides another opportunity to learn how hierarchy is maintained, which often results in better protection for the entire group.

This article is part of a series presented by the Fossey Fund’s gorilla program Senior Advisor Veronica Vecellio, focusing on the mountain gorillas the Fossey Fund protects and studies every day in Rwanda. Veronica has worked with these gorilla families for 20 years and shares her deep knowledge and insights about their lives.