Find out what a platypus has in common with a beaver or a dolphin. Learn what sets a platypus apart from a giraffe or a wild dog. Readers will compare key traits of platypuses--their appearance, behavior, habitat, and life cycle--to traits of other mammals. Charts and sidebars support key ideas and provide details. Through gathering information about similarities and differences, readers will make connections and draw conclusions about what makes this animal a mammal and how mammals are alike and different from each other.