Female macaques made 13 times as many friendly noises as males, two researchers from London's Roehampton University found in a study.

Nathalie Greeno and Stuart Semple listened to a group of 16 female and eight male macaques living on Cayo Santiago, also known as Monkey Island, off Puerto Rico for three months.

They counted the grunts, coos and girneys -- friendly chit-chat between two individuals -- while ignoring calls related to food or a predator, New Scientist magazine reported.

"The results suggest that females rely on vocal communication more than males, due to their need to maintain the larger social networks," Greeno said.

Females were also more likely to chat with other females than with males, the researchers found.

Greeno said this was likely because female macaques formed solid, long-lasting bonds as they stayed in the same group for life and relied on their female friends to help them look after their offspring.

By contrast, males roved between groups and chatted with both sexes equally.