Torpor or heterothermy corresponds to a state of depressed metabolism and is associated with specific metabolic, cellular and molecular adaptations that often occur on a seasonal basis. Yet the exact mechanisms and functioning of these changes are poorly understood. Interestingly, the potential of such extraordinary animal adaptation for human and animal health as well as other biomedical considerations has raised particular attention especially in the last decade. The strong metabolic and physiological adaptations of heterotherms can be of particular inspiration for current biomedical and pathological situations (e.g., obesity and related diseases, cardiovascular and metabolic dysfunctions, ischemia-reperfusion injuries, immune depression) and for the health and longevity of animal species, including humans.
Hibernation and Torpor in Mammals and Birds explores the physiological factors that control hibernation and torpor in birds and mammals. This text covers topics ranging from metabolism in hibernation to the role of endocrines, respiration and acid-base state in hibernation, and theories of hibernation. This book is comprised of 14 chapters and begins with an overview of some clear-cut definitions and why mammals and birds hibernate. The reader is then introduced to the variations from euthermia that have been observed among birds and mammals. To give some structure to this listing, the approach is phylogenetic, starting with the birds and proceeding through the primitive to the more advanced mammals. Subsequent chapters explains the process of entering hibernation and the hibernating state, itself; capability of a species in natural hibernation to arouse from that state using self-generated heat; physiological changes at the start of a spontaneous arousal; and physiological mechanisms underlying the ability of hibernators to rewarm. Consideration is also given to intermediary metabolism in hibernation, cold adaptation of metabolism in hibernators, and the response of hibernators to various extrinsic influences such as neoplastic growth, radiation injury, and parasitism and symbionts. This book will be of interest to students and researchers in fields ranging from zoology to physiology and biophysics.
This book summarises the newest information on seasonal adaptation in animals. Topics include animal hibernation, daily torpor, thermoregulation, heat production, metabolic depression, biochemical adaptations, neurophysiology and energy balance. The contributors to this book present interdisciplinary research at multiple levels ranging from the molecular to the ecophysiological, as well as evolutionary approaches. The chapters of this book provide original data not published elsewhere, which makes it the most up-to-date, comprehensive source of information on these fields. The book’s subchapters correspond to presentations given at the 14th International Hibernation Symposium in August 2012 in Austria. This is a very successful series of symposia (held every four years since 1959) that attracts leading researchers in the field. Like the past symposia, this meeting – and consequently the book – is aimed not only at hibernation but at covering the full range of animal adaptations to seasonal environments. For the next four years, this book will serve as the cutting-edge reference work for graduate students and scientists active in this field of physiology and ecology. .
A groundbreaking argument on how endothermy--arguably the most important innovation in vertebrate evolution--developed in birds and mammals "Vividly narrated and illustrated. . . . Provocative and fascinating for specialists and lay readers alike."--Southeastern Naturalist This pioneering work investigates why endothermy, or "warm-bloodedness," evolved in birds and mammals, despite its enormous energetic costs. Arguing that single-cause hypotheses to explain the origins of endothermy have stalled research since the 1970s, Barry Gordon Lovegrove advances a novel conceptual framework that considers multiple potential causes and integrates data from the southern as well as the northern hemisphere. Drawing on paleontological data; research on extant species in places like the Karoo, Namaqualand, Madagascar, and Borneo; and novel physiological models, Lovegrove builds a compelling new explanation for the evolution of endothermy. Vividly narrated and illustrated, this book stages a groundbreaking argument that should prove provocative and fascinating for specialists and lay readers alike.
This book gives an up-to-date account of the current knowledge of cold adaptation in animals, including phenomena like hibernation, daily torpor, thermoregulation and thermogenesis, metabolic regulation, freeze tolerance, anaerobiosis, metabolic depression and related processes. For the next four years - until the 12th International Hibernation Symposium - it will serve as a state-of-the-art reference source for every scientist and graduate student working in these areas of physiology and zoology.
Ecophysiology attempts to clarify the role and importance of physiological processes, such as digestion and respiration, in the ecological relations of species in their natural habitats. The basic principles and methods that are central to any ecophysiological study are outlined and discussed, including animal capture, blood collection, and the measurement of plasma components and hormone levels. Attention is paid to animal welfare and ethical considerations, and the question of stress and how to identify its presence in animals in their natural environment is approached through a series of case studies. Examples are given from a wide range of vertebrates living in deserts, cold climates and oceans, and recent findings on the physiological adaptations of Antarctic birds and mammals are a highlight of the book. This textbook will provide an introduction to the study of ecophysiology for advanced undergraduates and postgraduate students, as well as researchers in ecology, biodiversity and conservation.
This book provides an in-depth overview on the functional ecology of daily torpor and hibernation in endothermic mammals and birds. The reader is well introduced to the physiology and thermal energetics of endothermy and underlying different types of torpor. Furthermore, evolution of endothermy as well as reproduction and survival strategies of heterothermic animals in a changing environment are discussed. Endothermic mammals and birds can use internal heat production fueled by ingested food to maintain a high body temperature. As food in the wild is not always available, many birds and mammals periodically abandon energetically costly homeothermic thermoregulation and enter an energy-conserving state of torpor, which is the topic of this book. Daily torpor and hibernation (multiday torpor) in these heterothermic endotherms are the most effective means for energy conservation available to endotherms and are characterized by pronounced temporal and controlled reductions in body temperature, energy expenditure, water loss, and other physiological functions. Hibernators express multiday torpor predominately throughout winter, which substantially enhances winter survival. In contrast, daily heterotherms use daily torpor lasting for several hours usually during the rest phase, some throughout the year. Although torpor is still widely considered to be a specific adaptation of a few cold-climate species, it is used by many animals from all climate zones, including the tropics, and is highly diverse with about 25-50% of all mammals, but fewer birds, estimated to use it. While energy conservation during adverse conditions is an important function of torpor, it is also employed to permit or facilitate energy-demanding processes such as reproduction and growth, especially when food supply is limited. Even migrating birds enter torpor to conserve energy for the next stage of migration, whereas bats may use it to deal with heat. Even though many heterothermic species will be challenged by anthropogenic influences such as habitat destruction, introduced species, novel pathogens and specifically global warming, not all are likely to be affected in the same way. In fact it appears that opportunistic heterotherms because of their highly flexible energy requirements, ability to limit foraging and reduce the risk of predation, and often pronounced longevity, may be better equipped to deal with anthropogenic challenges than homeotherms. In contrast strongly seasonal hibernators, especially those restricted to mountain tops, and those that have to deal with new diseases that are difficult to combat at low body temperatures, are likely to be adversely affected. This book addresses researchers and advanced students in Zoology, Ecology and Veterinary Sciences.
Metabolic Ecology Most of ecology is about metabolism, the ways that organisms use energy and materials. The energy requirements of individuals (their metabolic rates) vary predictably with their body size and temperature. Ecological interactions are exchanges of energy and materials between organisms and their environments. Therefore, metabolic rate affects ecological processes at all levels: individuals, populations, communities and ecosystems. Each chapter focuses on a different process, level of organization, or kind of organism. It lays a conceptual foundation and presents empirical examples. Together, the chapters provide an integrated framework that holds the promise for a unified theory of ecology. The book is intended to be accessible to upper-level undergraduates and graduate students, but also of interest to senior scientists. Its easy-to-read chapters and clear illustrations can be used in lecture and seminar courses. This is an authoritative treatment that will inspire future generations to study metabolic ecology.
ROBERT WILLIAM McCARLEY Laboratory of Neuroscience, Department of Psychiatry, Harvard Medical School, Boston, and Brockton V A Medical Center, Brockton, Massachusetts The alternation of waking and sleeping, the daily course of the ad vancing and receding tides of consciousness, has long been a familiar part of our experience. But it is a new idea that autonomic and respiratory phys iology are equally and dramatically altered in a parallel fashion, and it is this concept that is summarized and developed here. The editors have drawn together thematically related chapters written by researchers with direct experience and a high level of expertise in the areas they address. The main theme is the relationship of general physiological alterations during sleep to cellular physiology and to the pathology of sleep. What is distinctive and especially appealing about this book on sleep is its emphasis on the autonomic and respiratory systems. This volume is, I believe, the first to explore these topics systematically and to blend phe nomenological description with possible cellular mechanisms and ties to clinical pathology. As such, this book should find an important place in the library of workers in the fields of sleep research, autonomic and respiratory physiology, and related neuroscience disciplines; it also belongs in the li brary of clinicians concerned with the disorders of sleep. This overview of topics and chapters gives an indication of their cath olicity.
