This Whale Travels Further Than Any Other Mammal Alive - Raises New Questions

It's a new record! US and Russian scientists recently documented the longest migration of a mammal ever recorded - a whopping 14,000 miles by a supposedly endangered gray whale. Now experts are wondering how endangered the species actually is.

According to a study recently published in the journal Biology Letters, researchers had used GPS tagging to monitor three western North Pacific gray whales via satellite as they migrated away from their primary feeding grounds off Russia's Sakhalin Island.

They were stunned to find that these whales traveled all the way across the Pacific Ocean and down the West Coast of the United States to Baja, Mexico. One of the westerners, named Varvara (the Russian rendition of Barbara), even visited three key breeding grounds frequented by eastern gray whales, which are found off North America.

"The fact that endangered western gray whales have such a long range and interact with eastern gray whales was a surprise and leaves a lot of questions up in the air," Bruce Mate, director of the Marine Mammal Institute at Oregon State University, and lead author of the study, said in a statement.

He explains that not only does this discovery update the textbooks, but it may even rewrite them, as western grays are supposed to be an endangered sub-species. Their eastern counterparts, on the other hand, used to be endangered, but conservation efforts led by the United States caused the animals to become delisted in 1996. Today they have a population estimated at more than 18,000 animals.

"Past studies have indicated genetic differentiation between the species, but [Varvara's visits to eastern breeding grounds] suggests we may need to take a closer look," Mate said. (Scroll to read on...)

And further studies like the work of Mate and his colleagues may wind up confirming something that study co-author Valentin Ilyashenko, of the AN Severtsov Institute for Ecology and Evolution - the Russian representative to the International Whaling Commission - has been suggesting for years.

He proposed that the "endangered" modern population of gray whales is actually a pioneering group of eastern whales looking to reclaim a former (and much more extensive) migration range that extends to Russian waters.

"The ability of the whales to navigate across open water over tremendously long distances is impressive and suggests that some western gray whales might actually be eastern grays," Mate explained.

But if that's true, he adds, "then the number of true western gray whales is even smaller than we previously thought."

It may be that western grays never existed. Another more distinct possibility is that the animals - which were thought to have gone extinct by the 1970s - actually are all gone, with the Sakhalin Island population made up of eastern pioneers or a mixed breed.

Much more research, including extensive genetic analyses of both sub-species, will now need to be launched to get to the center of this mystery.

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