WASHINGTON, Oct. 18 (UPI) — The answer to how gray whales survived the last ice age may come from a little-studied population of whales in the northwest Pacific, U.S. researchers say.
Gray whales normally feed on the seafloor at depths of no more than 150 feet and rely heavily on the shallow areas in Alaska’s Bering Sea for food, NewScientist.com reports.
But researchers at the Smithsonian Institution say during the last ice age sea levels were 400 feet lower than today and the Bering Sea was a land bridge, leaving little of the north Pacific shallow enough for such feeding.
Northern feeding grounds then might have supported only a few hundred whales, researcher Nick Pyenson said, but genetic studies show no sign of a population reduction during that ice age.
Pyenson says he believes the whales shifted to open-water feeding to survive, an idea supported by the discovery of a small population of non-migrating, open-water feeders living in the northwest Pacific year-round.
So why are there so few open-water feeders now?
The non-migratory, open-water whales would have been easy targets for early whalers, Pyenson said, so the migratory population has come to dominate.
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