Gorilla study reveals complex pros and cons of friendship
Friendship comes with complex pros and cons – possibly explaining why some individuals are less sociable, according to a new study of gorillas. Scientists at the Universities of Zurich and Exeter and the Dian Fossey Gorilla Fund examined over 20 years of data on 164 wild mountain gorillas, to see how their social lives affected their health.
Costs and benefits changed depending on the size of gorilla groups, and differed for males and females. For example, friendly females in small groups didn’t get ill very often but had fewer offspring – while those in large groups got ill more but had higher birth rates. Meanwhile, males with strong social bonds tended to get ill more – but were less likely to be injured in fights. The study may help to explain why such a wide range of traits have evolved in social animals, including humans.