The pups, born during September or early October, are covered with a long, black, wavy fur, which they lose when about two months old, and in its place comes a growth of silver-grey hair, which changes later into the ordinary brown colour of the full-grown animal.
The old males and females leave the island about the end of January, and are not seen again (except a few stray ones) till August in the case of the males, and until September in the case of the females.
The fact that the bulls arrive first leads one to the conclusion that their feeding-grounds must lie at a considerable distance and, in the journey therefrom, the males, being the stronger, should arrive before the females, who are heavy with young and probably make a somewhat leisurely progress, feeding by the way.
The rookeries vary in size, containing from half a dozen to four or five hundred cows; in the last case, of course, being an aggregation of smaller rookeries, each with its proprietor, in the shape of an old bull, lying in or somewhere near the centre. The normal rookery, as far as I could judge, seemed to be one that contained about forty cows, but once the nucleus was formed, it was hard to say how many cows would be there before the season ended, as females keep arriving for a period of about three weeks.
The young vary in length from three and a half to four and a half feet, are born within a few days of arrival and suckled for about a month, becoming enormously fat. The cow, who has not eaten during the whole of this time and has become very thin, then leaves the pup, but remains in the rookery for about two days, after which she escapes to sea, remaining there till the beginning of January, when she returns to the island to moult. The pups when weaned get such rough usage in the rookery that they soon make off into the tussock and sleep for about a month, living on their fat and acquiring a new coat. The noise in one of the large rookeries is something to remember—the barking of the pups, the whimpering and yelping of the mothers and the roaring of the bulls.
Another feature in connexion with the rookery is the presence of what may be called unattached bulls, which lie around at a little distance from the cows, and well apart, forming a regular ring through which any cow wishing to desert her pup or leave the rookery before the proper time has very little chance of passing, as one of these grips her firmly with his powerful flipper and stays her progress. The lord of the harem, in the meantime, hastens to the scene of the disturbance, whereupon the other bull decamps.
The sea immediately in the vicinity of a large rookery is generally swarming with unattached bulls, who may be seen with their heads out of the water eyeing each other and keeping a bright look out for escaping cows. Now and again one may see a bull in the water gripping a cow with his flipper, despite her struggles, and roaring at a couple of others who show up menacingly quite close to him.
It may be remarked that towards the end of the season changes in the proprietorship of a rookery are rather rapid, as continuous raids are made by individuals from the outside. The need of continuous vigilance and the results of many encounters eventually lead to the defeat and discomfiture of the once proud proprietor.
I have never seen two bulls fight without first indulging in the usual preliminaries, that is, roaring and advancing a few yards and repeating the performance till within striking distance. Then both animals rear high up, supporting themselves on the lower part of the body, and lunge savagely with their whole weight each at his opponent's head or neck, tearing the thick skin with their teeth and causing the blood to flow copiously. Several lunges of this kind generally finish the battle, whereupon the beaten one drops to his flippers and makes all haste towards the water, glancing fearfully behind him on the way. We have seen bulls with their snouts partly torn off and otherwise injured, but worse injuries must occur in the rare, desperate battles which sometimes take place between two very much enraged animals.
When a bull in the centre of a rookery has occasion to rush at an interloper, he does so without regard to anything in his way, going over cows and pups alike and very often crushing some of the latter to death. Again, it seems as if all the outlying bulls recognize the noise of the rookery bull, because each time he roars they all lift up their heads and take notice, whereas others who have just been roaring have not the slightest regard paid to them, except perhaps by one immediately concerned.