I don't know if it's true in the animal world, but I do know that the insect world is dominated by females. Ants and bees are a matriarchal society, where everyone is female except for the few winged males who exist to breed and die. There's also praying mantises and spiders (they're arachnids, but still), who can eat their husbands (and for mantises, their own children, so that they don't starve).