Having an extrovert personality could help you live longer, an international study of gorilla behaviour suggests.
Several theories exist about an apparent link, but one possibility is being good at social interaction could act as a buffer against the effects of stress.
Another is that extroversion indicates an individual has a good immune system. A team of researchers, led by the University of Edinburgh, studied almost 300 gorillas in zoos and sanctuaries in the US over 18 years.
Particular attention was paid to four personality traits: dominance, extroversion, neuroticism and agreeableness.
Extroversion (sociability, activity, play and curiosity) is linked with longer survival, the study concludes.