Gorilla games provide clues to human understanding
Gorillas play competitive games just like humans, according to scientists at the University of St Andrews.
The gorillas at San Francisco Zoo were observed over a period of five years playing with a variety of equipment.
The study found that gorillas like to keep games going and even give younger apes a fair chance to play.
The psychologists said the research would help trace the evolutionary origins of how humans understand each other.
Dr Joanne Tanner and Professor Richard Byrne watched gorillas play games to learn more about how apes are able to take account of each other's aims and abilities.
The playtime involved balls, bags and bits of leather.
Professor Byrne said: "Just like we would, the gorillas used gestures and displays of the object to keep the action going, and if the game slowed down or stopped a gorilla would use varied tactics to get it going again.
"The players were also considerate of other's abilities.
"An older and more skilled gorilla seeming to realise that if it used all of its potential, the younger one wouldn't be able to compete, so the older gorilla would slow down the pace."
The scientists said this kind of shared activity and joint attention with another person begins around nine months of age in humans.
Although this process has been suggested to be unique to humans, there have been some previous signs that our closest relatives among the African great apes, might also show similar abilities.
As a result of the new study, the scientists can map the evolution of this process back to the time that humans shared ancestry with gorillas, more than six million years ago.
Dr Tanner said: "Though the age at which gorilla games begin may be later in gorillas than in humans, and may depend on the challenges and artefacts available in a particular group's habitat, gorillas definitely enjoy the same kind of sporting competition we do."
The research has been published by the journal Animal Cognition.