SAN JOSE, Calif., Feb. 14 (UPI) -- U.S. scientists say a 13-year-old gray whale dubbed "Flex" has been tracked by satellite in a migration that's covered more than 5,300 miles.
Tagged in October in Russian waters off Sakhalin Island with a transmitter that reports his location to scientists each day, Flex was tracked past the central California coast on the weekend, the San Jose Mercury News reported Sunday.
Researchers have calculated his average swimming speed at around 4 mph and say he travels about 100 miles each day.
"These whales swim 24 hours a day," Bruce Mate, director of the Marine Mammal Institute at Oregon State University, said. "It's not an 8-hour shift. They don't feed during their migration, and they're really moving along."
Flex is a western gray whale and with only 130 known individuals the species is second only to the North Atlantic right whale in terms of large marine mammals approaching extinction.
Little is known of their behavior except that they summer off the Russian coast to feed.
Flex has so far journeyed more than 5,300 miles, almost directly across deep, open ocean waters from Russia to Alaska before turning south.
Though Flex is providing some first clues to the western gray's habits, researchers say they still don't know where he is going, whether long journeys such as his are normal or if he is traveling with other whales.
"That's the wonderful thing about tagging studies," Mate said. "You put the instruments on the animals and they tell their own stories. They go where they go."