Echolocation took whales to the depths
TOOTHED whales may owe their deep-dive ability to the power of echolocation.
Early whales preyed on nautiluses and squid, which rose to the surface waters only under cover of darkness. To take advantage of this midnight feast, the ancestors of today's sperm whales evolved to find their prey by echolocation. Once in place, this adaptation allowed whales to track molluscs into the inky depths during the day, say David Lindberg and Nicholas Pyenson of the University of California at Berkeley.