The western North Pacific gray whale can now claim the longest known migration distance. Bruce Mate, researcher at the Marine Mammal Institute of Oregon State University, and colleagues used satellite monitoring to tag seven of these whales living near Sakhalin Island. Mate and colleagues determined that one of the whales, a female, swam a round trip journey between Russia and Mexico—a distance of approximately 14,000 miles.
Varvara, the 9-year-old whale that broke the record, took 172 days to make the trip, according to the researchers' report. Researchers have long believed that western gray whales have remained isolated from eastern Pacific whales—but this new research is challenging that view.
Mate explains that usually, " . . . calves follow their mothers from breeding areas to foraging grounds," so these calves will typically stick to those routes, even as they become older. So, with Varvara's appearance in the eastern Pacific, there is speculation that some of these whales are born there. Questions on gray whale genetics have emerged as a result of this study. Perhaps western gray whales are merely an extension of the eastern population.
For more on whales (because really, who doesn't want that?), check out National Geographic's video on gray whale migration.