Mammals can be found on land and in the oceans, but what makes a mammal a mammal? Mammals are warm-blooded animals with hair or fur that feed their young with milk. For young learners, understanding what makes a mammal is an important STEM building block. In this book, young readers break down the basics of what makes a mammal. With full-color photographs to help reinforce the approachable text, readers come to a better understanding of which animals are classified as mammals and why.