Answered on Quora:
In most mammals, males are far more aggressive and even violent than females.
Take cats. I have had many cats in my life, sometimes whole herds of them, up to five at a time. Male cats are far more aggressive and violent than female cats. And they are so territorial that I can never have more than one male cat in a house. Frankly even one is an issue. The more I study male and female cats, the more I think they resemble male and female humans.
If you study other mammals – seals, elk, deer, etc., you will find much the same thing.