A small, mysterious group of whales off the coast of Russia, known as the western North Pacific gray whales, has shattered all the records of mammal migration. According to a new study published in the journal Biology Letters, the western gray whale now holds the crown for the longest known mammal migration.
Female gray whale travels 14,000 miles in 172 days
Without any celestial navigation or GPS, a 9-year old female gray whale swam from Russia to Mexico and back, traveling a total of 13,988 miles in 172 days. Notably, gray whales don’t eat during migration, which makes this achievement even more impressive. Until now, the humpback whale held the record for the longest mammal migration with 10,190 miles.
Researchers led by Bruce Mate of the Oregon State University placed satellite monitoring tags on seven western gray whales living off Russia’s Sakhalin Island. Mate said that Varvara, a female western gray whale, was the only one whose satellite monitoring tag remained intact as she migrated from feeding ground in Russia to breeding grounds off the coast of Mexico, and back again.
Mate and his colleagues have spent years tracking the migration of whales. Mate said western gray whales are a critically endangered species. The scientific community knew little about migratory paths of these mammals before this study. Until now, many scientists believed that the whales migrated from Russia to the South China Sea.
Two other gray whales also followed the same route
The latest tagging study shows that Varvara swam all the way to Mexico, crossing the Bering sea, the Gulf of Alaska to get down to the Baja breeding lagoons. Two other gray whales, a 6-year old female called Agent and 13-year old male Flex, took the same migration route. But their tags stopped working mid-way. All the seven whales were monitored via satellite during the 2011-12 migratory season.
Researchers were surprised to see that Varvara didn’t follow the same route on her way to Mexico and back. It means she was well aware of the general way, and didn’t need to stick to the coast to orient herself, researchers said.