Dolphin or porpoise?

"Beginning readers will learn to spot the differences between these aquatic mammals. . . . Leveled text relays what the mammals look like and how they behave. Each page then asks readers to name which one is shown in the photo. Answers appear upside down on the bottom of each page. . . . A See and Compare spread shows and labels each mammal side by side, while a Quick Facts feature lists even more information about their similarities and differences"--Provided by publisher.