Famed in story as ''the great leviathans'' sperm whales are truly creatures of extremes. Giants among all whales, they also have the largest brains of any creature on Earth. Males can reach a length of 62 feet and can weigh upwards of 50 tons. With this book, Hal Whitehead gives us a clearer picture of the ecology and social life of sperm whales than we have ever had before. Based on almost two decades of field research, Whitehead describes sperm whale biology, behaviour and habitat; how they organize their societies; and how their complex lifestyles may have evolved in this unique environment. Among the many fascinating topics he explores is the crucial role that culture plays in the life of the sperm whale, and he traces the consequences of this argument for both evolution and conservation. Finally, drawing on these findings, Whitehead builds a general model of how the ocean environment influences social behaviour and cultural evolution among mammals as well as other animals. The definitive portrait of a provocative creature ''sperm whales'' should interest animal behaviourists, conservationists, ecologists and evolutionary biologists as well as marine mammalogists.