I must wait to impress upon you the wonder of this fact. These love-antics of the stickleback, which are unique among fishes, would seem not to be exercised for the gratification of male desire, but for the purpose of inducing the female to lay her eggs,—to do her part in giving him offspring. Vainly do I ask myself the reason of this quite unusual sexual altruism. This is very extraordinary. The father woos the reluctant mother with passionate dances and his glad excitement is apparently intense. At this season the stickleback is transformed and glows with brilliant colours, his scales make silver look dim, his throat glows with flaming vermilion, he literally puts on a wedding garment of love.[21] And did I not fear being tedious by again waiting to point a moral, I should ask attention to this further proof given by the stickleback’s love joys to the truth which stands out in these life histories of pre-human parents. I mean this: the parent—the mother or the father—lives in the offspring. You will see how deep is the truth here. The parent is, after all, only the transitory custodian of the undying gift of life. The conduct of the mother stickleback is in sharp contrast with the devotion of the stickleback father. At once, having rid herself of her eggs, her desire would seem to be to escape any further responsibilities. She forces her way out of the nest by wriggling through the wall opposite the entrance. True, by doing this she renders a service to the nursery, as she thereby furnishes a channel through which a continuous supply of fresh, cool water can be driven, thus keeping the eggs bathed. This is the only work the stickleback mother does for the family. The male, after the first laying, may persuade her to add still further to the deposit of eggs. Sometimes, wearied with her one effort, she refuses. Thus forced, the stickleback seeks a second wife, driven into polygamous conduct through his desire for offspring. I know of no other case that is parallel with this. And the stickleback’s action has often been misrepresented. He is instanced as a polygamist; such is the fate that ever awaits self-sacrifice! When the nest is full the father stickleback mounts guard over the entrance of the nursery for nearly a month, and he watches by day and by night, defending his precious charge against all comers.