Book excerpt: Among all the large whales on Earth, the most unusual and least studied is the narwhal, the northernmost whale on the planet and the one most threatened by global warming. Narwhals thrive in the fjords and inlets of northern Canada and Greenland. These elusive whales, whose long tusks were the stuff of medieval European myths and Inuit legends, are uniquely adapted to the Arctic ecosystem and are able to dive below thick sheets of ice to depths of up to 1,500 meters in search of their prey-halibut, cod, and squid. Join Todd McLeish as he travels high above the Arctic circle to meet: Teams of scientific researchers studying the narwhal's life cycle and the mysteries of its tusk Inuit storytellers and hunters Animals that share the narwhals' habitat: walruses, polar bears, bowhead and beluga whales, ivory gulls, and two kinds of seals McLeish consults logbooks kept by whalers and explorers and interviews folklorists and historians to tease out the relationship between the real narwhal and the mythical unicorn. In Colorado, he visits climatologists studying changes in the seasonal cycles of the Arctic ice. From a history of the trade in narwhal tusks to descriptions of narwhals' vocalizations as heard through hydrophones, Narwhals reveals the beauty and thrill of the narwhal and its habitat, and the threat it faces from a rapidly changing world. Watch the trailer: http://www.youtube.com/watch?v=gHwaqdKyLCQ&list=UUge4MONgLFncQ1w1C_BnHcw&index=9&feature=plcp