Rosy love life for red-faced monkeys

Researchers have found that female monkeys prefer males with rosy faces – indicating the healthy glow of a flushed face is sexually attractive and signals good genes.

The collaborative team from the Universities of St Andrews and Stirling believe that this colouring – caused by high levels of testosterone – means that females may be attracted to a mate that has a healthy immune system and good genes.

Headed by Corri Waitt of the University of Stirling, in collaboration with the University of St Andrews, research found that, when presented with a choice, females of a common primate, the rhesus macaque, prefer males with red faces over those with pale faces.

There are links to human attractiveness and mate choice in that women with rosy cheeks and red lips would be considered attractive to the opposite sex.

Ms Waitt said: “Humans seem to use colour as a cue to mate quality. For instance, many people view red lips and a “healthy” glow as attractive and could use these as indicators of perceived heath.

“Similarly, nonhuman primates probably use colouration, in this case red facial colouration, as a means to assess mate attractiveness and health.

“Nobody really knows why – but it could play a role in competition with other males or female mate choice.

“We have found that the females do seem to be interested in the bright colouration.”

It is well known that throughout the animal kingdom certain species (especially birds, reptiles, fish and insects) use brilliant displays of colour to attract mates, though such sexual colouration is restricted to primates in mammals. The theory that female primates are attracted by male colouration dates back to the theories of Charles Darwin, but this is the first experimental evidence to support of the idea.

Adult male macaques undergo a hormonally increased reddening of facial and anogenital skin during their mating season and this is induced indirectly by an increase in testosterone levels.

The researchers presented 6 females macaques in Puerto Rico with computer-manipulated images (one pale and one red-faced) of 24 wild adult males. They measured duration and direction of gaze to each face to measure visual preferences. They found that females spent much longer looking at the red faces and used gestures such as lip-smacking to show their interest, indicating a clear preference to the red faces, suggesting that male colouration is a cue to the mating quality of the male.

The researchers explained: “Colouration is a prominent cue involved in mate choice in many animals.

“The preference of red faces over pale faces may reflect selection of high-quality males as red colouration is linked to testosterone production.”

“There are links with human attractiveness – colouration may effect human attractiveness, and could be the reason that women use blusher to give themselves rosy cheeks.”

The research is published today in Biology Letters, a journal of the Royal Society

NOTE TO PICTURE EDITORS:

IMAGES OF THE COMPUTER-GENERATED MALE MACAQUES AND REAL IMAGES OF FEMALE / MALE MACAQUES ARE AVAILABLE FROM GAYLE COOK – CONTACT DETAILS BELOW.

PLEASE NOTE THAT THE RESEARCHERS ARE UNAVAILABLE FOR INTERVIEW AT THIS TIME.

HOWEVER, THE FULL ARTICLE IS AVAILABLE FROM GAYLE COOK.

*** ‘Evidence from rhesus macaques suggests male coloration plays a role in female primate choice’ appears in Biology Letters.

ENDS

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