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BOB HIRSHON (host):
Giant evolution. I’m Bob Hirshon and this is Science Update.
Blue whales and their cousins are the largest creatures that have ever lived, but they haven’t always been this big.
NICHOLAS PYENSON (Smithsonian National Museum of Natural History):
The whales we have today are substantially bigger than anything we find in the fossil record.
HIRSHON:
In fact, Smithsonian National Museum of Natural History curator Nicholas Pyenson and colleagues report that these filter-feeding baleen whales are today up to triple the length of their ancestors just three million years ago. That’s when glaciation in the northern hemisphere led to nutrient runoff along coastlines, increasing seasonally abundant patches of prey. The researchers write in the Proceedings of the Royal Society B that larger whales could travel longer distances and more efficiently take advantage of this bonanza.
PYENSON:
Large baleen whales only got large very recently, and different species all got large at once from much smaller ancestors.
HIRSHON:
I’m Bob Hirshon, for AAAS, the science society.
Story by Susanne Bard