Regarding sexual dimorphism among primates, humans falls into an intermediate group with moderate sex differences in body size but relatively large testes.
Males will invest more in ejaculation when competitors are in the immediate environment of the female. There is a lot of energy that is expended when a male is guarding his mate. He will situate himself near an area that possesses valuable resources that the female needs. These, and other, types of methods have the male playing defense by protecting his mate. Proceedings of the Royal Society B. This is done in an attempt to decrease mating attempts with the female that the focal male prefers, hence decreasing sperm competition. Views Read Edit View history.