If you're a gorilla, you're big and strong. You're twice the size of a female. You establish your physical dominance over any male you meet. You live with your harem of two to five females. Your females are monogamously faithful to you. Your penis is one inch long. Sex is quick.

If you're a gibbon, you mate monogamously for life. You live with your mate and your children. You sing to your mate. She sings back to let you know where she is. You and your mate are the same size and look identical. You start each morning with a half-hour of loud hooting to frighten other gibbons away from your forty acres of forest.

If you're a chimpanzee, you live in a group of fifty individuals. When a female is ovulating, she has sex with every male in the group. You have a large penis, large testicles, and ejaculate lots of sperm. You reproduce not because you dominate females or other males, but because your sperm is more active than other males' sperm (i.e., you're healthier than other males).

If you're a baboon, you live in a troop that varies from 10 to 200 individuals, depending on habitat, time of year, and predation.[1] You make friends with other males. When another male threatens you, your friends back you up. You avoid fighting. Fighting leads to injuries, and lions eat injured baboons.[2] You also make friends with females. Female baboons mate with their male friends. They like males who have many friends.

http://en.wikibooks.org/wiki/Relationships/How_Women_Select_Men