Beneath the cold waters off northern Norway, sperm whales have quietly solved a problem that physics would seem to make impossible: how to sleep underwater when your own head wants to carry you to the surface. Researchers from the University of St. Andrews and the Université de Neuchâtel have discovered that these giants release air through their blowholes while napping — a bubble-by-bubble negotiation with buoyancy that varies depending on how deep they rest. The finding, published in the Journal of Experimental Biology, answers one ancient question about these creatures while opening another