Exploring bachelor gorillas’ social behaviors

Many of you have had the opportunity to observe our gorilla bachelor group of Mbeli, Kal and Gunther grow up and develop over the past few years. Spending most of their days together in Habitat 4 in the gorilla area of The Ford African Rain Forest, these three were introduced to each other in 2012. Gunther and Kal were 6 and 7 years old respectively at that time, and were just leaving their family group. Mbeli, 10 at that time, had just recently left a separate bachelor group.  

Being introduced at a young age was key for this group’s success in bonding. While Mbeli was considerably bigger than the other two boys, Kal and Gunther had grown up with each other since they were infants and had established much stronger social bonds. Observing them over the years as they grew up, visitors had the opportunity to see all three taking part in a game of chase or wrestling. As they were adolescent boys, the occasional skirmish was always inevitable as well. Again, all of these interactions helped them developmentally as they got older.

Recently we have started to observe some behavioral changes within this group. All three gorillas are now almost fully grown at right about 350 pounds each. With Kal and Gunther having caught up to Mbeli in size, it was time for them to test the social hierarchy again. With this came an increase in display behaviors to see how much each individual could push and test the others. Displays such as body posturing, chest beating, vocalizing, throwing of objects, or charging are not uncommon behaviors with bachelor gorillas sorting out their social hierarchy. While these sort of behaviors usually do the trick to resolve a conflict, they do occasionally have physical confrontations as well. It comes with the territory of being a silverback gorilla, and we always monitor them closely.

In order to help accommodate these developments in the group, we have made some changes as well. Visitors stopping by Gorilla Habitat 4 will now notice a wider variety of items in the habitat, such as burlap bags, wood wool bedding, branches and fire hose cubes. These items are used by the gorillas to display toward each other. Gunther especially approves of throwing the fire hose cubes around to show how tough he is. These items help redirect aggression into more positive forms of behavior. We have also added more roundabout opportunities for the group to be able to run in circles without anyone hitting a dead end.

As Mbeli, Kal and Gunther continue to grow here at Zoo Atlanta, their behaviors will continue to change. Eventually they will reconfigure themselves into a new hierarchy and settle down into a cohesive group once again, similar to our adult bachelor group of Kekla, Stadi and Charlie, who can be found in Habitat 1. So be sure to come out and visit the gorillas soon and watch the unique interactions they have with each other. It can be quite exciting.
(Photo by Hayley T.)
Josh M.
Lead Keeper, Primates