A newly published long-term study of mountain gorillas has provided the most comprehensive insights yet into why female gorillas, and sometimes other group members, continue to carry infants after they die. Drawing on nearly 22 years of continuous observation, our team documented maternal behavior following 141 cases of infant death – the largest dataset of its kind for any ape species, and far exceeding the only two previously published cases in mountain gorillas.
Corpse carrying has been observed in a number of primates and even non primates such as dolphins. In the current study, our team found in more than 60 percent of cases, mothers carried their deceased infants, sometimes for days or even weeks.
The study was led by James Munyawera, who first came to the Fossey Fund as a University of Rwanda student for our undergraduate field courses. He went on to become one of our research assistants, collecting data about the gorillas using our long-term behavioral protocol, and then was promoted to Field Data Officer, responsible for organizing all the data collection on the many gorilla families we study. Munyawera was then awarded a fellowship at the University of Oxford and has recently begun a Ph.D. program at the University of Oregon with a focus on gorilla genetics.
“While spending six years observing mountain gorillas in the forest and witnessing how they react when an infant dies, I became interested in this topic to understand what might be influencing the different types of behaviors we see,” says Munyawera.
“These moments are emotionally powerful and understanding behaviors related to these losses could deepen our understanding of the gorillas’ social bonds, caregiving and how they experience loss. Using our long-term data was an excellent opportunity to understand these behaviors more systematically.”