http://www.scientificamerican.com/article.cfm?id=bitch-evolved-girls-cruel
And if this little pigtailed girl is anything like the rest of her gender, in just a few years’ time she will unfortunately morph into an eye-rolling, gossiping, ostracizing, sarcastic, dismissive, cliquish ninth-grader, embroiled in the classic cafeteria style bitchery of adolescent female social politics.
If that strikes you as misogynistic, rest assured it’s merely an empirical statement. (Rest assured, also, that I’m afraid I have much in common with this tactical style, and I have great respect for more refined Machiavellians, so I’m not casting stones here.) In fact, over the past few decades, scholars from a variety of disciplines—including developmental psychology, evolutionary biology and cultural anthropology—have noted a striking difference in the standard patterns of aggression between reproductive-aged males and females. While teenage boys and young male adults are more prone to engage in direct aggression, which includes physical acts of violence such as hitting, punching and kicking, females, in comparison, exhibit pronounced social aggression, which includes such obnoxious things as mentioned in the various acts of bitchery listed above.
GOATMILK: An intellectual playground 
Any real scientist knows evolutionary biology isn’t science. Science is testable and it makes predictions. Evo devo does neither. It’s merely retrospective explanation, and many explanations can often be provided for any given feature of human behavior. It’s higly highly higly speculative, so it seems silly to invoke it as a source of authority. It also inherently and very unintuitively reductionist, taking complex features of human behavior, like our love for art for instance, and contorting it into some underlying drive for survival. We would lose little if we rejected it entirely for ultimately the explanations it provides are simplistic and vacuous.