But what about the apparently useless differences between the sexes?
Ornaments like ruffs and crests, exotic colouring, or antlers grown so large that they hindered rather than helped in a fight?
“Choosing a mate is one of the most important decisions made in one’s lifetime and one of Darwin’s core components of sexual selection,” Geary says.
“Sex and reproduction complicate our lives in many ways, the most fundamental of which involve the demands of finding a mate.
The females then arrive and choose the males with the deepest croaks and best territories.