Essentially what Darwin realized was that sexual dimorphism, particularly where it makes the male spectacularly different from female is not always the outcome of inter-male conflict, very often it is, we saw examples of the films of stags, of erm elephant seals, those kinds of animals where the dimorphic differences appear to be the result of inter-male conflict, for instance elephant seals are seven times heavier, the males are seven times heavier than the females on average because sheer weight is what wins those astonishing battles they have on the beaches when they, they kind of lunge at each other.