"Because the drift dives are quite short (averaging around 12.7 minutes in duration) and are broken by the need for the whale to move to the surface to breathe, it seems that they sleep over short interrupted periods," said Miller. "Cat naps for sperm whales, perhaps?" he suggested. The scientists made the connection when one of their vessels, off the coast of northern Chile, nearly crashed into a group of seemingly oblivious sperm whales. Terrified and in tears, one of the researchers captured the harrowing moment on this video. The boat, under sail power alone, unintentionally touched one of the whales. Only then did the whale seem to wake up and flee, along with its companions. Still photography shows the vessel was in eye-shot of the whales, but the researchers now suspect that side of the whales' brains might have been in dreamland at the time. The findings support other research that whales and their kin aren't exactly heavy sleepers. Dolphins and killer whales don't seem to sleep at all during their first month of life, according to Jerome Siegel, director of the Center for Sleep Research at the University of California at Los Angeles. Siegel and his colleagues drew that conclusion after observing killer whales and their calves at SeaWorld San Diego and mother dolphins and their calves at two public sites in Russia's Black Sea. Since the young cetaceans don't appear to sleep at all during this period, the mothers also seem to get very little rest. "Somehow these seafaring mammals have found a way to cope with sleep deprivation, facilitating rather than hindering a crucial phase of development for their offspring," said Siegel. "Their bodies have found a way to cope, offering evidence that sleep isn't necessary for development, and raising the question of whether humans and other mammals have untapped physiological potential for coping without sleep," he added.
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