Book excerpt: Physiological Adaptations: Desert and Mountain discusses the bodily modifications of different animals accordingly to desert and mountain environments. Covered in this book are the basic concepts of physiological adaptations; biophysical principles of acclimization to heat; partitional calorimetry in the desert; the mechanism of sweat in relation to heat; the effects of heat on the cardiovascular and respiratory systems; and the nutritional and metabolic aspects in relation to heat. The book also covers the effects of altitude on work performance; the physiology of respiration at altitude; and the body fluids, body composition, and metabolic aspects of high-altitude adaptation. The text is recommended for biologists and natural historians who would like to know more about how animals that have deserts and mountains as habitats adapt and survive.