The underwater environment poses multiple problems to animals that have evolved to live at the surface which need to be overcome if the animal is to utilise the marine setting as a habitat and foraging environment. These problems are associated with the inability of the terrestrial respiratory surface to extract oxygen from water and thus the resulting hypoxic conditions, and the increasing degree of pressure resulting from the overlying column of water, the effects of which become increasingly problematic as the nature of the dive becomes longer and deeper, respectively. …
