The comparative physiology of seemingly disparate organisms often serves as a surprising pathway to biological enlightenment. How appropriate, then, that Robert Elsner sheds new light on the remarkable physiology of diving seals through comparison with members of our own species on quests toward enlightenment: meditating yogis.
As Elsner reveals, survival in extreme conditions such as those faced by seals is often not about running for cover or coming up for air, but rather about working within the confines of an environment and suppressing normal bodily function. Animals in this withdrawn state display reduced resting metabolic rates and are temporarily less dependent upon customary levels of oxygen. For diving seals—creatures especially well-adapted to prolonged submergence in the ocean's cold depths—such periods of rest lengthen dive endurance. But while human divers share modest, brief adjustments of suppressed metabolism with diving seals, it is the practiced response achieved during deep meditation that is characterized by metabolic rates well below normal levels, sometimes even approaching those of non-exercising diving seals. And the comparison does not end here: hibernating animals, infants during birth, near-drowning victims, and clams at low tide all also display similarly reduced metabolisms.
By investigating these states—and the regulatory functions that help maintain them—across a range of species, Elsner offers suggestive insight into the linked biology of survival and well-being.
Industry Reviews
"Elsner, a founding father of seal physiology, discovered many of the fascinating adaptations that allow marine mammals to dive very deep and for long periods of time. He taught these marvels to a host of young scientists around the world. This book is a treasure trove of fundamental concepts and insights into the control of metabolic rate in animals and humans. Elsner explores the special adaptations that allow certain well adapted animals to live and thrive in extreme or hostile environments, often drawing on the fruits of his own research expeditions from India to the Arctic and Antarctic. Elsner's comparisons between the diverse survival strategies of these animals, and his insightful description of their unifying similarities help us appreciate and understand these extraordinary physiological achievements. In a fascinating segment, Elsner includes an inquiry into the strategies humans have developed for slowing down their metabolic rate. Elsner prods us to consider that the control of metabolic rate achieved by meditating yogis, while poorly understood, is worthy of being studied alongside the better-known strategies for slowing metabolic rate, notably those used by long-diving seals. Elsner pulls together a broad spectrum of solid physiological science in an accessible and engaging form; his book should appeal not only to students of comparative biology but also to students of yoga, and generally to any reader who is curious about the wonders of the natural world."--Warren M. Zapol, Massachusetts General Hospital and Harvard Medical School, US Arctic Research Commission
