Were more prone to violence.
No, most animals are more prone to violence than humans.
For example, wolves are like relentess and unstoppable gangs of canniballistic murderers!
Predatory animal species kill in order to survive. Man kills for a lot of reasons, very few of which have to do with eating. Name one species that has killed millions of it's own kind. I can think of only one.
This is supposed to be a discussion about biology, not politics. If there were 6 billions cats on this planet, they would fight and kill each other, too!