Summary of lecture given on August 31 1950 to the Australian Institute of Navigation.

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 evolution of Pinniped behaviour and the mechanisms which underlie it are a consequence of having to cope with two seemingly incompatible sets of environmental constraints. The physiological adaptations for concomitant functioning in two media with very different physical characteristics have produced correlated behav ioural modifications. The energetic demands of reproduction and foraging are idiosyncratic because each activity occurs on opposite sides of the air/water interface. As a result, the mating system must reconcile aquatic design for such functions as locomotion and thermoregulation, with the terrestrial requirements for successful pupping. Similarly, the ecology of this dual habitat prescribes the rules governing the behaviour of the neonate and its interactions with its mother.

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 evolution of Pinniped behaviour and the mechanisms which underlie it are a consequence of having to cope with two seemingly incompatible sets of environmental constraints. The physiological adaptations for concomitant functioning in two media with very different physical characteristics have produced correlated behav ioural modifications. The energetic demands of reproduction and foraging are idiosyncratic because each activity occurs on opposite sides of the air/water interface. As a result, the mating system must reconcile aquatic design for such functions as locomotion and thermoregulation, with the terrestrial requirements for successful pupping. Similarly, the ecology of this dual habitat prescribes the rules governing the behaviour of the neonate and its interactions with its mother.

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 evolution of Pinniped behaviour and the mechanisms which underlie it are a consequence of having to cope with two seemingly incompatible sets of environmental constraints. The physiological adaptations for concomitant functioning in two media with very different physical characteristics have produced correlated behav ioural modifications. The energetic demands of reproduction and foraging are idiosyncratic because each activity occurs on opposite sides of the air/water interface. As a result, the mating system must reconcile aquatic design for such functions as locomotion and thermoregulation, with the terrestrial requirements for successful pupping. Similarly, the ecology of this dual habitat prescribes the rules governing the behaviour of the neonate and its interactions with its mother.

Pinnipeds are a fascinating group of marine mammals that play a crucial role as apex predators and sentinels of the functioning and health of marine ecosystems. They are found in the most extreme environments from the Polar regions to the tropics. Pinnipeds are comprised of about 34 species, and of those at least 25% live permanently in tropical zones. This book reviews and updates current research on the biology, marine ecology, bio-monitoring, and conservation of tropical pinniped populations, including their behavior, anthropogenic stressors, and health. It also looks at challenges to be faced for the conservation of tropical pinnipeds, many of which are threatened species.