The return of blue whales to the waters off Canada and Alaska may mean the marine mammals have managed to re-establish a migration pattern not seen since long before commercial whaling ended in 1965.

Blue whales are the largest creatures to have ever existed, and their numbers were decimated during the peak period of commercial whaling between 1908 and 1965.

Since the species’ population did not show signs of recovery after whaling ended, it was feared that the animals had lost the cultural knowledge to reclaim their habitats.

But analysis of photographs taken of 15 blue whales off British Columbia and Alaska since 1997 by Canadian and U.S. researchers showed that four were also seen off California.

It’s believed the species is migrating into the Gulf of Alaska because there isn’t enough krill to sustain them solely in coastal California.

The research was conducted by the Cascadia Research Collective in Olympia Washington in coordination with NOAA and Canada’s Department of Fisheries and Oceans. Results were published in the journal Marine Mammal Science.

Photo: NOAA