Gorillas learn about injustice and revenge by playing tag

Gorillas may hone their social skills and fighting tactics by playing tag, according to researchers who filmed the great apes at play in zoos across Europe.

They found that individuals often carried out "hit-and-run" strikes on other members of the group, taking a swing at them before running away. The playful attacks usually gave rise to a lumbering chase around the gorilla enclosure, with the chaser becoming the chased once they had landed their own retaliatory blow.



Footage shows them chasing and clobbering each other while displaying the open-mouthed expression of apes at play. Psychologists led by Marina Davila Ross at Portsmouth University, recorded 21 gorillas in colonies at zoos in Berlin, Hannover, Munster, Stuttgart and Zurich.

The gorillas' behaviour has strong similarities to the children's game tag, but is perhaps more like a playful exchange of punches that must be well-judged to ensure it does not escalate into a more serious fight.



The researchers found that the gorillas only gave chase if they were struck with a sufficiently heavy blow. Lighter strikes were ignored. "Not only did the gorillas in our study hit their playmates and then run away – chased by their playmates – they also switched their roles when hit, so the chaser became the chased and vice versa," said Davila Ross.

The game is thought to prepare gorillas for conflicts that might arise over food or mates. "This kind of playful behaviour lets them test their group members and learn what the borders are," she added. "How far you can go with an individual is important for social interactions later in life." The study, published in the Biology Letters journal, suggests humans are not the only apes to have a sense of injustice and be motivated to seek revenge.