There is some research suggesting that a significant portion of "normal" school children may not evaluate school-based violence (student-on-student victimization) as negatively or as being unacceptable as much as adults generally do, and may even derive enjoyment from it, and they may thus not see a reason to prevent it, if it brings them joy on some level. Both males and females have differently toll on how they bully their victims. Men/boys usually bully other boys in physical ways like pushing, punching, and aggression, whereas females are more likely to spread rumors, talk bad about the person, etc. Although they are different ways in which boys and girls do bullying a lot of the ways may be similar as well, and they both can be bullied or be the bullies.
Bullying can also be perpetrated by teachers and the school system itself. There is an inherent power differential in the system that can easily predispose to subtle or covert abuse (relational aggression or passive aggression), humiliation, or exclusion — even while maintaining overt commitments to anti-bullying policies.