Forever associated with Melville's classic Moby Dick, sperm whales are mysterious deep-sea diving creatures who can hold their breath underwater for more than an hour at a time. Author Alison Imbriaco describes how these mammoth cetaceans, known as the most social and loyal of the whales, communicate and hunt for prey using a special sense called echolocation. She details the threats endangering them, including ocean and noise pollution, entanglements...