What is a mammal? What did the first mammals look like? How do mammals survive in their environments? This book is sure to answer many readers' questions about the evolution of mammals and how they can be classified. Readers will learn important life science concepts from life cycles to migration. The book discusses mammal adaptations, such as polar bears keeping warm and fennec foxes keeping cool. Color photographs supplement fascinating text to hook readers' attention. Diagrams and sidebars are sure to add to the learning experience. From huge elephants to tiny bumblebee bats, this book gives a great overview of the magnificent world of mammals.