So, selection favours an intermediate body size and powerful long legs, explaining why competitive males have not evolved greater size and the female lemur retains her power and social dominance. There are further evolutionary forces at play. Just as we saw with the genitals of ducks, sexual conflict is also involved. Lemur females are promiscuous but males have evolved a sneaky trick to monopolize their valuable egg without physical dominance or fighting one another: they have semen that hardens like rubber to form a ‘copulatory plug’.
