Eat, Poop, Die: How Animals Make Our World

In this enjoyable study, biologist Roman (Listed) explores the vital roles animals play in ecosystems across the globe. In the forests of northwestern North America, Roman explains, trees next to salmon-filled streams grow faster than their counterparts because salmon carry nutrients from the ocean as they swim inland, where bears consume them and deposit those nutrients in the soil through their urine, fostering the growth of plants that, by providing shade, keep the stream cool and conducive to salmon reproduction. Roman also describes how whales redistribute nutrients in the ocean by feasting in deep waters and expelling the remains near the surface, and how parrotfish “build” beaches by chewing up coral and limestone and excreting it as sand. Surveying the positive and negative ways humans influence their environment, Roman notes that conservationist efforts to reintroduce sea otters to Southeast Alaska revived the region’s kelp forests because the otters ate the urchins that had overrun the kelp. Animal farming, on the other hand, has been disastrous, with liquid manure from factory farms polluting groundwater and contributing to acid rain. The prose is pleasantly lighthearted (“Does a bear crap in the woods? Sometimes”) and the big-picture perspective illuminates the intricate ways organisms interact to shape their environments. This playful pop science outing satisfies. Photos. (Nov.)