We are wreaking havoc on the planet. Scientists predict that half of all living species will be obliterated by the end of the century, and in this age of man-made destruction it seems obvious we should try to salvage some of what’s left. But as Jon Mooallem discovers in his ambitious and fascinating first book, “Wild Ones,” American conservation today presents a far greater conundrum than deciding what to save or even how to save it. Such efforts force us to reconsider our relationship with other species and to confront what may be our obsolete fantasy of “wilderness.” Most of all, they force us to rethink the human animal.

Mooallem, a contributing writer for The New York Times Magazine, seamlessly blends reportage from the front lines of wildlife conservation with a lively cultural history of animals in America, telling stories of people past and present whose concern for animals makes them act in ways that are sometimes unexpected, sometimes heroic, and occasionally absurd. Thomas Jefferson obsesses over finding an American mammoth; a “sharp-witted hippie” ignites a worldwide movement to save the whales; a man lives in a cage and learns to dance with a whooping crane. There is very little self-righteousness or sentimentalism here, just an intense desire to understand why we do what we do when it comes to wild animals in America. Mooallem, who observes conservationists at work from California to Manitoba, narrates his experience while questioning his own assumptions along the way.

The book concentrates on three endangered species — the polar bear (doomed media darling), Lange’s metalmark butterfly (obscure beauty), and the whooping crane (conservation success story with major caveats). Mooallem watches hungry polar bears waiting for ice to form so that they can hunt. He counts butterflies in a fragile riverbank ecosystem, “a narrow band of land at the anonymous, industrialized fringes of town, the kind of place not easily reached by any bus line, but around the corner from where a transit company parks its buses at night.” He follows an improbable annual migration of captive-born whooping cranes led by men flying ultralight planes, each one dressed in what Mooallem describes as “a long, frumpy gown and white hooded helmet with mesh covering the face.” The costume looks like “a beekeeping suit crossed with a Ku Klux Klan get-up.”

But this isn’t “Wild America.” There are no lingering close-ups or hushed moments of thrilling intimacy with wild animals. Which is part of the point. The art critic John Berger has argued that looking at animals gives us access to an unvarnished truth, whereas Mooallem suggests that looking at animals is hardly an act of pure observation. “From the very beginning, America’s wild animals have inhabited the terrain of our imagination just as much as they’ve inhabited the actual land.” He calls them “free-roaming Rorschachs” and points to the instability of the stories we weave around them to underscore their fiction. Pigeons were once considered lovely but are now seen as a filthy nuisance. Bears were once regarded as monsters, but when Theodore Roose­velt refused to shoot a wounded bear tied up for his sporting pleasure, the country seized on this moment of mercy and the beloved teddy bear was born. Children are surrounded by imaginary animals — butterflies on pajamas, animal-themed classrooms, books and movies full of fish and foxes that behave like people. As Mooallem digs through the layers of meaning that have “been draped over animals, and on top of each other like translucent silk scarves,” one starts to get the feeling that maybe we have never been able to really see wild animals at all.