Close this search box.
Close this search box.

When gorillas groups interact, anything can happen

During our daily mountain gorilla monitoring, Fossey Fund trackers and researchers often get to see interesting behaviors, all of which are recorded for our scientific database. One type of behavior that is important, since it can lead to group changes and even injuries, is an interaction between two groups.

Our trackers and research assistants take detailed notes, photographs and other information, and produce reports with moment-by-moment action like this one, from an interaction between Giraneza’s group and Mafunzo’s group, on March 10.

Silverback chest beatsOur tracker team that follows Mafunzo’s gorilla group reached them at 9:06 that morning and found the gorillas resting. But at 9:18, they saw Giraneza’s group approaching, so they called the trackers of Giraneza’s team, to let them know. Giraneza’s trackers reached the spot at 9:37 a.m., and within a few minutes, silverback Mafunzo approached within 7 meters of silverback Giraneza, taking a strut stance (a show of aggression). However, the females of both groups remained calm and in the background.

Then the action started, as recorded by our staff:

At 9:23 a.m., Mafunzo replied (to Giraneza’s strut stance) by hooting and chest beating.

At 9:29 a.m., Giraneza slapped the ground at Mafunzo, who replied by hooting and chest beating.

At 9:31 a.m., Giraneza took a strut stance posture at Mafunzo, who replied at 9:33 a.m., by smashing plants.

At 9:34 a.m., Giraneza smashed plants at Mafunzo. He chest beat again at him at 9:36 a.m.

At 9:36 a.m., Mafunzo withdrew and he bit young female Ubuhamya for resting.

At 9:42 a.m., Mafunzo hooted and chest beat in 30 meters from Giraneza who replied by chest beating.

At 9:44 a.m., Mafunzo hooted and chest beat in 40 meters from Giraneza who replied at 9:47 a.m., by chest beating.

From 9:49 a.m. to 10:04 a.m., Giraneza chest beat 3 times, slapped the ground twice and smashed plants once at Mafunzo.

At 9:52 a.m., adult female Nyandwi aggressed Mafunzo.

At 9:55 a.m., Mafunzo’s group started moving toward the Kupoteza area while Giraneza’s group moved down to the Munoga area.

At 10:06 a.m., Mafunzo hooted and chest beat at Giraneza from 100 meters away. Giraneza responded by smashing plants.

At 10:08 a.m., Mafunzo slapped the ground at  Giraneza  from 100 meters away.

At 10:10 a.m., Giraneza chest beat at Mafunzo.

At 10:14 a.m., Mafunzo hooted and chest beat from 200 meters away. Giraneza replied by slapping the ground.

At 10:19 a.m., Giraneza chest beat at Mafunzo.

The interaction ended at 10:25 a.m., with the two groups separated by 200 meters. When our trackers left, the groups were separated by 1.5 kilometers. Both groups were calm and feeding. During the interaction, there were no transfers, no wounds and they moved only 20 meters. But, as seen in this report, there were many displays, all of which were carefully counted and recorded by our staff.