You're standing in an elementary school play yard and a couple of shouts erupt. It's two boys, brawling it out over some little problem that they had with each other. Maybe it's a girl. It doesn't matter. The teachers get involved, and both boys go to the principal's office.
Do you think that the way everyone saw those two boys would change? How much punishment would they get in? Or would everyone just shrug and say "Oh, boys will be boys."?

Now imagine the same situation with two girls. That's right, two sweet, kind little girls giving each other bloody noses over some little thing.

Everyone, school staff, other kids, parents, would be shocked. Because girls are sweet little things who are always nice. Suddenly, those girls would be bad kids.

So instead of coming to blows, girls are passive aggressive. Little hate notes, exclusion, compliments that weren't intended to be nice. Because it's not flashy like brawls, the teachers don't notice it. And anyone who stands out and refuses to partake is a "bitch", or "cold", because she sticks with her own opinions. Anything can cause this form of bullying: jealousy, insecurity, a look, an unacknowledged wave, a need to climb the popularity ladder. Some girls will sacrifice others to make it into the close knit cliques.

Since girls are raised this way, with mental assault possibilities coming from all sides, we can be very wary of other girls later on in our lives. Especially victims of this form of bullying.