Gorilla friendships have an impact on their health.
Gorillas with strong social bonds are more likely to get sick
Boffins have found that male primates who have strong social bonds in the wild were more likely to get ill.
Experts with the Dian Fossey Gorilla Fund and the universities of Exeter and Zurich claim that their findings highlight the forces that affect the evolution of social behaviour and could perhaps explain why some human beings are less sociable than others.
The researchers examined over 20 years of data on 164 gorillas in Rwanda.
Dr. Robin Morrison, lead author of the research at the University of Zurich, explained: "Having a lot of strong social relationships is often really good but sometimes it isn't.
"It's possible that males expend more energy by having close social ties, as they have to defend females and offspring, and the stress of this may reduce their immune function. If you are a very popular male in your group, that comes with a lot of responsibilities."