Bullying is not easy to define, namely because there is no one way to bully. It comes in many forms, from physical playground scuffles to verbal attacks. Even governments have a hard time defining it, often referred to as a repeated behaviour with the
intent to hurt someone either physically or emotionally. By this definitions, there are many ape and monkey bullies, too. In fact,
any hierarchical society is likely to have bullies in its midst.
An unfortunate monkey at the bottom of the hierarchy is repeatedly attacked and picked upon by those higher up in the group - they are sometimes beaten up every day. Bullying amongst rhesus macaques, for example, seems to release tensions among the higher-ups. Bullying seems to reinforce their bonds, as they have a common enemy. Therefore, it seems to be an effective way to unite the more dominant macaques. Even removing the victim or "scapegoat" does not prevent the behaviour. The dominant macaques would simply turn on another low-ranking monkey.
The same exists amoung chimpanzees. To get to the top, alpha males often bully any chimp who stands in their way. Chimps are natural bullies, every male reaching adolescence starts his rise in the dominance hierarchy by teasing females. Once a chimp has shown his power to all the females, he can challenge and fight other adult males.
The thing that defines this aggressive behaviour as bullying is that it is not immediately related to survival. Dominants attack subordinates out of the blue, for no apparent reason. However, this unsolicited harassment may serve a useful purpose. According to researchers, bullying helps dominant animals to intimidate their subordinates, and that this has clear evolutionary benefits. It ensures that the dominant individuals have better access to food and to the opposite sex.
For chimps, the more a female is bullied by a particular male, the more that male gets to mate her, which leads to him having more offspring with her.
Even in captivity, where food is plentiful, bullying is still frequent in both rhesus macaques and chimps. That means the monkeys and apes can invest more time and energy into maintaining their status. This is simply how these animals are wired.
Read more: http://www.bbc.com/earth/story/20160822-why-bullying-is-such-a-successful-evolutionary-strategy
