Rosenfield, Semple et al
Female monkeys spend more time staring at males with strong masculine facial features. But it’s not clear why their gaze lingers like this.
Face structure often varies between male and female members of a species. In humans, men tend to have heavier brows, squarer jaws, deeper-set eyes and thinner lips than women.
Some researchers believe that facial masculinity signals mate quality, but this is hotly contested. To find out, Kevin Rosenfield, who was at Roehampton University in the UK when the study was performed, and his colleagues examined facial preference in monkeys.
They studied 107 free-ranging female rhesus macaques on the island of Cayo Santiago in Puerto Rico. Each female was simultaneously shown two photos of male faces, one of which was more masculine than the other. Masculine features included bigger jaws, longer noses, and smaller eyes.
When the two faces had