Discover what a humpback whale has in common with a gibbon or a caribou. Learn what sets a humpback whale apart from a hedgehog or a sloth. Readers will compare key traits of humpback whales—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.