We teach our students of behavioural science that one first defines a research problem, and then the most appropriate animal is selected to investigate hypotheses. The reverse order of events is improper: a particular class of animals should not be studied for its own sake. In the case of the Pinnipeds (seals, sea lions, fur seals and walruses) the organism and the problem are essentially the same. The research questions presented in this volume in one way or another relate to survival in two worlds, the ocean for foraging, and the terrain at its edge or frozen above it for breeding. The...