For the past two years, western Pacific gray whales have been tracked making an unusual journey across the Aleutian Chain. The endangered marine mammals have started their journey from Sakhalin Island in the Russian Far East, traveled across the Bering Sea during the summertime, and then moved down to the California coast to breed. Now, scientists are saying that it’s possible that the tagged creatures might not be western Pacific gray whales after all.

The Associated Press reports that the journey of a nine-year-old female named “Varvara” is making researchers at Oregon State University’s Marine Mammal Institute wonder if the tagged animals might be eastern Pacific gray whales – a different species that’s seen a rapid recovery in its population size in recent decades. That’s because the western group doesn’t usually make that crossing, preferring to breed in the south China Sea. Varvara is the third whale to have taken that route.

Right now, estimates put the western gray whale population at 130. You can keep track of Varvara’s location on the Marine Mammal Institute's website.