Video: The ejaculation-inducing cries of promiscuous female macaques during sex arouse other local males
MALE Barbary macaques eavesdrop on their neighbours having sex to make sure they don鈥檛 miss out on the fun 鈥� and to give their sperm a chance to compete in the great fertilisation race.
Female Barbary macaques (Macaca sylvanus) cry out during sex, and the call stimulates ejaculation in the male. The females can also slightly modify the call, making the male less likely to ejaculate.
Dana Pfefferle of the German Primate Center in G枚ttingen and her colleagues recorded ejaculatory and non-ejaculatory calls produced by females at , a primate park at Rocamadour in France where Barbary macaques roam freely.
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They then hid a loudspeaker among the plants, not far from a resting male, and played the recorded cries (Animal Behaviour, ).
The researchers found that males reacted more quickly and more strongly in response to ejaculatory calls. The macaques looked in the direction from which the call came for roughly twice as long as they did for the non-ejaculatory call. They also approached nearby females and checked their genitals for the swelling that indicates they are fertile. 鈥淚t was quite a strong reaction,鈥� says Pfefferle.
The researchers speculate that the female鈥檚 ejaculatory call signals that the race is on for her egg. Keen to get in on the race, other males approach her.
