Crested macaque monkeys follow friends before family
Crested macaque monkeys look to their friends for "guidance" more readily than to their family, according to scientists.
The University of Portsmouth team that made this discovery measured how quickly one monkey would follow the gaze of another.
Gaze following is very important in macaque society - helping the animals to find food or spot potential danger.
The findings are published in the journal Animal Behaviour.
They reveal, the researchers say, the importance of friendship in complex societies, where animals live together and rely on one another.
End Quote Jerome Micheletta University of Portsmouth
In some contexts... friendship can even be more important than family ties”
"We [study these primates] to try to explain how our own social system evolved," explained lead researcher Jerome Micheletta from the University of Portsmouth.
"We want to know why we humans form groups and... social relationships."
Mr Micheletta, who is studying the behaviour of macaques as part of his PhD, said that previous research on social primates had already shown how important friendship was in terms of "fitness, reproductive success and the reduction of stress".
"But there's little evidence about how social relationships and friendship actually affect behaviour," he explained to BBC Nature.
To find this out, he and his colleagues studied the animals' habit of following the gaze of another.
The team worked with captive monkeys at Marwell Wildlife Zoological Park in Hampshire.
During the experiments, the scientists had to wait for two macaques to sit together, facing one another.
"Then I would wave an interesting item - like a piece of fruit - [so that] the monkey that could see me looked towards the item."
The other macaque would naturally follow that animal's gaze, turning to see what had distracted their partner.
The speed of the animals' gaze-following reaction did not change if they were paired with a more socially dominant member of their group or if their partner was a relative.
But the animals did follow the gaze of their partner much more quickly if the two "shared a strong positive bond", Mr Micheletta explained.
The scientists were able to "measure friendship" between two monkeys by recording how much time two macaques chose to spend in each others' company, and how much time they spent grooming one another.
"Friendship is important for [these animals] to cope with day to day life and survival," Mr Micheletta told BBC Nature.
"In some species, friends are probably as important as family and dominance status.
"In some contexts - like gaze following - friendship can even be more important than family ties."