Female monkeys shout during sex, says study

Researchers found that females yelled during 86 per cent of all sexual encounters. When females shouted, males ejaculated 59 per cent of the time. However, when females did not holler, males ejaculated less than two per cent of the time.

To see if yelling resulted from how vigorous the sex was, the researchers counted the number of pelvic thrusts males gave and timed when they happened. They found when shouting occurred, thrusting increased. In other words, hollering led to more vigorous sex.

“Counting monkey pelvic thrusts is admittedly quite weird, but it’s science. You get used to it,” Pfefferle said.

Male and female Barbary macaques are promiscuous, often having sex with many partners. This means sperm levels can get quite drained. The females shout when they are most fertile, so males can make the most use of their sperm.

The results of the study have been published in the Proceedings of the Royal Society B journal.