Return to the Sea - 9780520270572

"This book portrays the life and evolutionary times of marine mammals, from giant whales and sea cows that originated 55 million years ago and walked on land, to deep-diving elephant seals and clam-eating walruses of modern times. Some animals like the hippo-sized herbivorous desmostylians and aquatic sloths were evolutionary experiments that did not survive. This fascinating account of the origin of various marine mammal lineages written for the non-specialist is set against a backdrop of geologic time,changing climates, and geography. The thread of evolution runs through the book and helps us to understand the today's diversity of marine mammals and marine-mammal responses to environmental challenges. The story of the evolution of these fascinating animals, their lives and habits, offers a valuable perspective and in some cases lessons for the future. Berta also informs readers about current controversies in the field of marine mammalogy, presenting a balanced view based on careful evaluation and interpretation of the evidence. She explores patterns of change taking place today such as changing food webs and predator-prey relationships, habitat degradation, global warming, and the effects of humans on marine-mammal communities. The future of marine mammals depends on each of us, scientists as well as the informed public, working together to avoid crises before they develop or appropriately managing those that do arise"--