What do you give a curious child in the throes of the potty-humor stage? This book might be an option. Readers will be introduced to 10 creatures from around the world that use their posteriors in unusual ways. Learn how the tiny herring cuts the aquatic cheese to signal its position at night to other herrings in its school—and how those watery toots almost started a war between nations. Or learn why the beaded lacewing is a deadly houseguest for termites across North America. Each chapter follows a uniform format: introducing key facts, like the species’ name, size, and habitat range in a blob-shaped callout box set on top of an appealing double-page illustration. The following double-spread discusses on verso the creature’s delightful derriere and how it provides a natural survival advantage, with a bonus fact below the informative paragraphs; opposite, a full-page illustration provides some humorous context above a feature inviting readers to rate that creature’s butt on a descending scale from “terrific tushie” to “boring backside.” There is no bibliography or further-reading suggestions—which is a real bummer—so curious readers looking for more information are on their own. That aside, the book is a gas.