The Fossey Fund’s nearly six decades of mountain gorilla monitoring and research show just how dynamic and fascinating their lives are. Gorilla groups aren’t static but rather are part of an ever-changing story.
Here we present some of the highlights and milestones of one historic group that was first studied by Dian Fossey and is still shaping the mountain gorilla population today!
Dian Fossey’s study groups
When Dian Fossey began her pioneering work in 1967, she closely observed two main gorilla groups in Rwanda’s Volcanoes National Park. She called them Group 5 and Group 4. Remarkably, these two groups went on to create entire dynasties, to the point that each of the gorillas daily monitored by the Dian Fossey Gorilla Fund today is likely related to one or the other.
Group 5 has the most-extraordinary story, branching into more than 16 new groups. Eight of these groups still exist and are actively studied today. Together, they account for more than 73% of the gorillas currently living in the area.
Group 5, first studied by Dian Fossey, is a key to the success of many mountain gorilla families since then.
Group 5: Stable for 26 years
When first seen in 1967, Group 5 had 15 members, including dominant silverback Beethoven and dominant female Effie, who together became ancestors of the largest-known gorilla lineage. While Beethoven’s genetic contribution is assumed because of his dominant status, Effie’s legacy is genetically proven and continues today through her matriline.
Group 5 stayed stable for 26 years. Dominance among males shifted twice, from Beethoven to Icarus and then to Ziz, but Effie remained the key female.
When Ziz died in 1993, Group 5 ended. At that point, it had grown to 37 gorillas and split into two groups led by the subordinate young silverbacks – 18-year-old Pablo and 16-year-old Shinda.
Silverback Pablo was the first leader of a group that formed in 1993 and still exists today.
And then Pablo and Shinda groups
Pablo led 20 gorillas, including Effie and all her female offspring, plus an ambitious young male – and Effie’s first grandson – Cantsbee, who was 14 at the time. Shinda’s group included older females and their offspring.
Both Pablo’s and Shinda’s groups then grew and evolved significantly.
Shinda’s group lasted 15 years, ending after his death in 2008. It then split into Ntambara and Ugenda groups, with Ugenda’s group later splitting again. Three ambitious males also emigrated from Shinda’s group, becoming longtime solitary gorillas and occasionally forming their own groups. The last of these was Inshuti’s group, which ended in 2024. Today, only Ntambara’s group remains from the Shinda group’s branch.
Pablo’s group set all kinds of records, growing to an incredible 65 gorillas by 2006. Eventually, the group’s size became challenging to manage and members started leaving, forming smaller groups or joining others.
Today, the group continues and has 20 members. Now led by Ubwuzu, the great-grandson of Effie on his father’s side, the group retains Pablo’s name in honor of its founder.
One remarkable record held by Pablo’s group is that males who left the group throughout these years formed 11 new groups; six are still thriving today. The leadership gene inherited from their ancestors Beethoven and Effie has certainly borne fruit. And the dynamics of these groups have taught us much about the lives of the mountain gorillas.
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 more than 20 years and shares her deep knowledge and insights about their lives.
