Reviews On Thin Ice: The Changing World of the Polar Bear by Richard Ellis Share this:EmailFacebookTwitterPinterestPocketRedditPrint By Science News January 29, 2010 at 12:20 pm The natural history of polar bears entwines with human history in this science writer’s ode to the world’s largest land carnivore. ON THIN ICE: THE CHANGING WORLD OF THE POLAR BEAR BY RICHARD ELLIS Alfred A. Knopf, 2009, 400 p., $28.95.