when they anesthetized dolphins and orcas in their care, it killed them, because they simply stopped breathing. Sleep, however, is a physiological requirement of every mammal on earth. So, when and how do they manage it? In the case of killer whales (and most dolphins), the trick involves shutting down only half of their brain during a given sleeping session, remaining just awake enough to swim, surface, and breathe, all in a slow, rhythmic pattern. In the wild, where orcas swim almost constantly, this is done in large pods of up to twelve whales, who line up in a wide arc and draft off each
...more
