Males have more pronounced personalities than females - from humans to house sparrows, according to new research.
Consistent personality traits, such as aggression, are also more important for females when looking for a mate than they are for males.
Research from the University of Exeter draws together a range of studies to reveal the role that sexual selection plays in this disparity between males and females.
A concept originally developed by Charles Darwin, sexual selection is the theory that evolutionary traits can be explained by competition between one sex - usually males - for mates and by (female) mate choice.
The study shows that in most species males show more consistent, predictable behaviours, particularly in relation to parental care, aggression and risk-taking.
Females, on the other hand, are more likely to vary their behaviour. They are also more likely to respond to these traits and therefore seem to be ‘choosier’ about the personality of a potential mate.
The research draws on several studies, dating back to 1972. It is the latest study in a growing body of research from a University of Exeter team that links gender personality differences to sexual selection.
The authors believe sexual selection may hold the key to this variation. While physical attributes resulting from sexual selection, from dazzling peacock tails to over-sized antler horns are well known, there has been much less of a focus on the impact on personality.
Wiebke Schuett of the University of Exeter (U-E), who led the study, says, “Our study is the first to bring together research about the impact of sexual selection on personality in humans and other animals.”
“This body of research suggests that male personality could have evolved in much the same way as signs of physical attractiveness - to help attract a mate,” says team leader Sasha Dall of U-E.
“Scientists have not given the role of sexual selection in shaping animal personality much consideration in the past. We hope that our work will pave the way for further research in this rather overlooked subject,” says Dall.
These findings were published in Biological Reviews.