A stallion

And that you are! Your body is nicely toned, your fur recently shampooed, and you are (of course) a bit larger than any of the mares your age. Natural selection simply wants you to dominate. You think yourself decently handsome, but not necessarily in a cocky (Yours is ten whole inches, by the way.) manner. The mares seem to appreciate you, especially at THIS time of year! Go get 'em, kid!