The Mammalian Diving Response: Lessons from a Seal

Abstract

Limitation of oxygen at the cellular level invariably leads to progressive disruption of biochemical processes and physiological function. If the oxygen deficit exceeds the organism's tolerance to asphyxia, death will result. Studies of mammalian divers such as seals may provide clues for medical science in its battle against hypoxia induced cellular disruption. The mammalian diving response is a collection of physiological events that preserve the function of hypoxia sensitive tissues while somehow maintaining the animal's ability to swim, feed and function at depth. Using the example of the Northern Elephant Seal (Mirounga angustirostris), the physiology of the diving response will be reviewed and its effect on the behaviour and ecology of the species will be presented. Recent studies using Magnetic Resonance Imaging (MRI) techniques have led to new discoveries in the field of diving hypoxia. These data will be presented and discussed.