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The first is the ancestor to all whales was probably not a deep-sea diver, as had been previously proposed. Instead, the research suggests it was most likely a crocodile-type shoreline ambush hunter. Today's sperm whales can dive for more than one hour to depths greater than 4,000 feet below the water's surface. If the "mother of all whales" had tried such a dive, its bones probably would have shattered to bits. The study also indicates toothed and baleen whales independently evolved anatomical and behavioral abilities to cope with the bends, with toothed whales developing the skills long before baleen whales did. This provides evidence that the two major groups of whales split from their common ancestor early on and went down their own evolutionary paths, perhaps explaining the tremendous amount of diversity seen among whales today. Erich Fitzgerald is a noted whale evolution expert and a paleontologist at Australia's Museum Victoria. Fitzgerald described the new research as "quite important, and it presents a novel hypothesis on the evolution of one of the critical aspects of cetacean biology." He said that "it seems the odontocetes evolved their 'tool kit' for deep diving and hunting in the dark using sound, very early on," while "the baleen whales were on a different evolutionary timetable, 'modernizing' much later in their evolutionary history." "This is fascinating, and we need further analyses of relevant fossils to test these ideas," Fitzgerald added.
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