Without GPS, celestial navigation or even sight of a shoreline, a 9-year-old gray whale named Varvara made a 13,987 mile journey from Russia to Mexico and back, breaking the known record for mammal migration. And she did it all before lunch.
Okay, so it took her 5½ months. While gray whales almost never eat during migration — it’s still an impressive trek to make on an empty stomach.
The feat was recorded in a study published today in the journal “Biology Letters” by Oregon State University biologist Bruce Mate, chair of the school’s Marine Mammal Institute. Mate and his colleagues spent years tracking the migration of Western North Pacific gray whales, a critically endangered species living off the coast of Russia. What they found surprised them, in more ways than one.
First, there was the impressive, trans-oceanic journey, which bested the previous record (a 11,706-mile round trip by a humpback whale reported in 2011) by more than 2,000 miles. The migration from feeding grounds in Russia to breeding areas off the coast of Mexico was made by at least two other whales: a 13-year-old male named Flex and a 6-year-old female called Agent. All three were tagged and monitored via satellite during the 2011-2012 migratory season.
The duration and difficulty of the journey has challenged Mate’s assumptions about how gray whales migrate.
“I’ve had to revise my thinking completely,” he said in a phone interview.
Previously, most gray whales were thought to remain on their respective coast lines (either in Asia or North America) and set their path by keeping an eye — or an ear — on the shore, like a swimmer following a lane line. They learn their migratory route from their mothers, who lead them from breeding grounds in the south to feeding areas up north during their first year of life, and simply repeat that journey year after year.
But Varvara made her trip without the help of any of that. Moving faster than her counterparts on either coast, she made her way from Russia to Alaska by swimming straight across the Bering Sea, an area with deep water and little in the way of landmarks to guide her. Instead of retracing her steps on the return journey, she swam a new path — this time hugging the Alaskan coastline. At least one of those routes was not the one her mother had taught her, suggesting previously unsuspected navigational abilities.
“Needless to say, we’re impressed,” Mate said. “How she did it remains to be seen.”
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SOURCE: The Washington Post, Sarah Kaplan