Polar bears—fierce and majestic—have captivated us for centuries. Feared by explorers, revered by the Inuit, and beloved by zoo goers everywhere, polar bears are a symbol for the harsh beauty and muscular grace of the Arctic. Today, as global warming threatens the ice caps’ integrity, the polar bear has also come to symbolize the peril that faces all life on earth as a result of harmful human practices. Here, the acclaimed science writer Richard Ellis offers an impassioned and moving statement on behalf of polar bears—and all they stand for.

Ellis gives a vivid and brilliantly articulated picture of earth’s largest land predators—including their hunting, mating, and hibernation habits. Polar bears are exceptionally well suited for hunting—especially when it comes to ringed seals, their favorite prey, which they can smell from more than a mile away. But as the ice melts in the Arctic, the ability of polar bears to find food diminishes in spite of their incredible physical capacities. Some bears will vainly take to the water in search of ice on which to hunt, and many of them swim until they drown. In the past twenty years alone, the world population of polar bears has shrunk by half. Today they number just 22,000.

Still, On Thin Ice is an ode, not an elegy: Ellis reminds us that the extinction of the polar bear—and the disappearance of our ice caps—is not inevitable. While the killing of polar bears remains a matter of ritual solemnity among the Inuit, U.S. government officials continue to balk at placing the polar bear on the endangered species list because doing so would place the bears’ territory off-limits for oil drilling. As the polar bears’ habitat disappears beneath them, their survival rests entirely on our willingness to take such critical steps.

Urgent and stirring, On Thin Ice is both a celebration and a rallying cry on behalf of one of earth’s greatest natural treasures.