The Better to Eat You With: Fear in the Animal World
Joel Berger
304 pages, hardcover: $29.
University of Chicago Press, 2008.

Where the Wild Things Were: Life, Death and Ecological Wreckage in a Land of Vanishing Predators
William Stolzenburg
288 pages, hardcover: $24.99.
Bloomsbury, 2008.

A world without fear sounds nice, doesn't it? Liberated from our dread of nosy bosses, environmental catastrophe, cocktail-party conversation and clumsy dentistry, we could wander the planet with a spring in our step and a gleam in our eye. From our modern perspective, fear is an annoyance, an inconvenient emotion to be fenced out or shot down. But fear, as two new books make clear, has its uses  -- not only as a critical survival strategy, but also as a supporting force for the entire natural world.

Wildlife biologist Joel Berger understands fear more intimately than most. For starters, the guy's been chased by an angry mother moose. Berger begins his memoir The Better to Eat You With at the base of Wyoming's Teton Range, where he watches two reintroduced wolves attack a fatally blase herd of elk. In the six decades since wolves hunted here, Berger wonders, have elk lost their traditional fear of wolves? And if so, how many bloody lessons will they, and other species, need to get it back?

Such questions lead Berger on a whirl of research expeditions to Alaska, Siberia, Greenland and elsewhere, in an attempt to understand fear among moose, caribou, bison and other species. In Alaska's Talkeetna Mountains, where moose live with both wolves and bears, he uses a portable loudspeaker to play wolf howls and raven caws. (The birds are drawn to predators and the carrion they produce.) He also tests neutral sounds, such as running water, and a few unfamiliar noises including those of howler monkeys. The Talkeetna moose seem more fearful than other Alaskan moose that live without predators, a finding strengthened when Berger, using a pitching arm honed by college baseball, starts hurling snowballs loaded with wolf urine and bear scat. He observes that moose familiar with predators flee from the odors  -- though not from snowballs peed upon by a perhaps too-willing field assistant. Back in Wyoming, he learns that while such fears can fade, they quickly reappear when needed; both elk and moose regain their predator savvy within a generation.

Berger happily shares the human foibles that dog the pursuit of science. On the Canadian border, he tangles with customs officials suspicious of his stash of frozen scat; after a long stint in the Alaskan bush, he finds that his only clean pair of pants actually belongs to his wife; and in one frigid camp after another, he faces his own recurring fear of low caffeine supplies. Berger's discursive field tales show, above all, why so many large wild animals remain mysterious: Each data point represents Herculean effort, each solid answer a career.

Berger and his pitching arm also make an appearance in William Stolzenburg's Where the Wild Things Were, a deft and engaging exploration of the ecological power of predation. Biologists once believed that the world was run from the bottom up: The number of plants dictated the number of plant-eaters, which dictated the number of plant-eater eaters, and so on. But in 1960, a trio of biologists suggested that influence cascaded from the top, with predators eating enough herbivores to keep the world green. "Nearly fifty years later," Stolzenburg writes, "the community of ecologists knows that there are indeed certain keystone predators, some as unlikely as an orange starfish, with powers to rock entire ecosystems to their foundations."

In Zion National Park, the Kaibab Plateau of Arizona and other places around the world, Stolzenburg reports, predator declines cause far-reaching collapses and contortions. Exploding herbivore populations strip the landscape bare; midsized predators such as foxes and raccoons multiply and put painful pressure on bird communities. (Or not: In Southern California, coyotes appear to protect native birds by killing housecats.) In Venezuela, tropical ecologist John Terborgh witnesses an especially stark example: Howler monkeys, which normally live in close-knit groups, react to a loss of predators, and the resulting overtaxed food supply, by retreating into isolation. They may even resort to infanticide.

Humans, of course, now reign as the ultimate predators, the only species capable of bringing the planet to a boil. But alone in the woods or even in the backyard  -- especially in the West  -- we're still vulnerable, still walking around with scanty pelts and exposed guts. And we know it. Even imagined predator reintroductions  -- such as the "Pleistocene rewilding" of North America suggested by a group of scientists in 2005  -- arouse intense controversy.

The nature writer Craig Childs observes that we seldom eat top predators  -- tuna, yes, but not mountain lion, or bear, or wolf. Whether the aversion is rooted in taste, practicality, or something deeper, it seems the longstanding order of eater and eaten is difficult to ignore, even for us hypercivilized bipeds. Perhaps that's a good thing. For as both Berger and Stolzenberg remind us, a life without fear is the most dangerous of all.