Equipped to survive the frigid arctic tundra, polar bears are powerful swimmers and agile hunters. Learn about the lives of these incredible mammals and how they manage to stay at the top of the food chain in their wintry habitat. Discover how threats such as global warming and oil spills pose a danger to them, and find out the role people play in enabling their survival. The World of Mammals reveals the fascinating physical and behavioral characteristics of a diverse sampling of animals and offers a detailed account of each animal's habitat and natural history. This series also teaches children the pivotal role humans play in ensuring these creatures' continued survival. Through vivid photographs and lively text, young readers discover how crucial it is to show respect for the mammals that live in our backyards and the untamed wilderness.