Readers will laugh aloud at the silly antics of a pair of opinionated sea mammals in a tale presenting one side of a debate when read front-to-back and the other side when read back-to-front, slyly revealing the way identical facts can be used to support opposite positions. A boastful whale and a showboating otter compete in a battle of words to prove that each is the greatest animal ever to swim the seas. Read one way, the first-person text brags about whales’ superiority; read the other way, it extols how much better otters are. Using true information about the two marine species to make both arguments, Kate Messner’s adroit text and Brian Biggs’s giggle-worthy artwork brilliantly illustrate how the same words can be used to express contradictory opinions when speakers have a one-sided view of the world. Includes factual back matter about language usage and the actual similarities of whales and otters.