Focusing on the physiological and behavioral factors that enable a species to live in a harsh seasonal environment, this book places the social biology of marmots in an environmental context. It draws on the results of a forty-year empirical study of the population biology of the yellow-bellied marmot near the Rocky Mountain Biological Laboratory in the Upper East River Valley in Colorado, USA. The text examines life-history features such as body-size, habitat use, environmental physiology, social dynamics, and kinship. Considerable new data analyses are integrated with material published over a fifty-year period, including extensive natural history observations, providing an essential foundation for integrating social and population processes. Finally, the results of research into the yellow-bellied marmot are related to major ecological and evolutionary theories, especially inclusive fitness and population regulation, making this a valuable resource for students and researchers in animal behavior, behavioral ecology, evolutionary biology, ecology and conservation. "Armitage … presents a lifetime thesis (22 chapters in six parts) incorporating forty years of fieldwork, highlighting the yellow-bellied marmot as a representative example among the better-studied species from North America to Russia." Dr Rajith Dissanayake, The Biologist Focusing on physiological and behavioral factors, this book places the social biology of marmots in an environmental context. Kenneth B. Armitage is Baumgartner Distinguished Professor Emeritus of Ecology and Evolutionary Biology at the University of Kansas. His forty-year research project on the yellow-bellied marmot in the Upper East River Valley, Colorado, is the second longest continuous study of a mammal. He is an elected Fellow of the Animal Behavior Society and the American Association for the Advancement of Science and an Honorary Member of the American Society of Mammalogists for 'distinguished service to the science of mammalogy'.