Though both birds work together and with the same zeal, it must be noted that the mother’s guard over the young is more strict than is that of the father. When the mother is sitting, nothing, not even a wrangle with her next-door neighbour, will induce her to move from her post. Whatever happens, there she stays until her turn for relaxation comes. But the cocks are more easily led astray. Their combativeness causes them to forget family affairs. Often much harm is done by these quarrels in the crowded rookery, which occur frequently and in spite of the protests of anxious neighbouring parents, who are seen trying to make peace. The most curious habit of these delightful birds has still to be recorded. They have developed a taste for games, such as leaping, diving and boarding the ice-floes. These amusements are indulged in by the adults, who band themselves in large companies, and play occupies much of their time. To gain the necessary freedom for this fun from their homes, and without leaving the chicks to perish, a most instructive device has been evolved by the penguin parents. The birds with young families “pool their offspring” in groups, which are left in charge of a few conscientious birds, both cocks and hens, who act as nurses; they ward off the attacks of the sukas, and keep, or try to keep, the chicks from wandering. The holidaying parents bring food at intervals—when their consciences smite them—and they remain faithful to their own crêches. This is, I think, the earliest example of what must be regarded as a premeditated experiment in co-operative child-rearing. For the parents it doubtless has many advantages. These remarkable birds certainly appear to find a quite unusual joy in life: we read of the ecstatic attitudes they will frequently assume and the weird “chant de satisfaction” which they utter during play when all is well with their world. Yet the fact, already noted, must not be overlooked that the death rate in the rookery is enormously high; indeed, a frightful mortality often overtakes the young chicks when left by their parents. The children pay for the escape on the part of the parents from the sacrifice parenthood must entail.