Animals are everywhere on Earth. There are many kinds of animals, and they can be very different. How did they get to be so different? They made changes to adapt to their diverse environments. This book looks at some of the most interesting adaptations animals have made and explains why they happened. Dolphins are more closely related to sheep than they are to other fish. How did this happen? The ancestors of dolphins spent a lot of time in shallow water eating fish. Gradually their bodies changed, their arms became flippers and their legs vanished. Insects have also made adaptations. The largest insect that has ever lived was a dragonfly 300 million years ago. It had a 30-inch wingspan. This was possible because there was more oxygen in the atmosphere then and they could get the oxygen they needed to power a body that size. Bats make sounds and listen for the echoes from the objects around them to picture their environment. Submarines use a sonar system that is similar when they see objects underwater. Interesting facts about twenty animals are included in this book that is well illustrated with numerous photographs. Reviewer: Kristin Harris