But within forty-eight hours of their landing the cows give birth to their “pups.” And it is for this purpose, and not for mating, that they come to land. Within a few days of the birth, however, the females are “in use” again. This is the critical period in the life in the rookery. For the bulls now become frenzied with excitement and fight most viciously one with another, each hoping to possess himself of his opponent’s harem. Each tries to seize the other by the fore flipper, and, failing in this, the fangs are buried in the back. They hold tenaciously, each trying to force the other to relax his hold; but commonly this vice-like grip is maintained till the skin gives way, leaving great bleeding rents. Sometimes the contest rages till one or both is fatally wounded. Often during such duels an idle bull, hitherto unable to secure a harem, will rush in and capture that of one of the combatants! In the management of the harem the bull is an adept. Whether he has five cows or fifty, he is, says Dr. Lucas, “master of the situation.” His will is law. Not that it is always tamely accepted as such, but the result is the same. If a cow becomes restless, and moves about, a warning growl usually quiets her. If the movement is persisted in and an attempt to escape evident, the bull is up at once with a show of fierceness and in chase. He may simply strike her down with his open mouth. Often in doing so his sharp canines tear a gash in her skin. He may even seize her in his mouth and deliberately throw her, or carry her back into the harem. If the cow thinks she has a chance to get away she may try to outrun him. If she miscalculates the distance he seizes her, after a few swift bounds, by the skin of the back, or by the hind flipper, and tosses her, often torn and bleeding, into the family circle. As a rule, however, she avoids this seizure by turning and facing her lord and master, and biting him in the breast and throat. But all to no purpose. In spite of her violent protests he pushes her backwards before him into the fold. Sometimes in her efforts to improve her position she runs up to, and is seized by, a rival bull. Her lord speedily asserts his ownership by getting a grip wherever he can on the would-be truant. Then begins a tug-of-war between the two bulls, during which the wretched victim of their rage may be torn in pieces. By the elimination in each generation of the more querulous and discontented, the peculiarly gentle and passive nature so characteristic of the females has been developed.