A female gray whale named Varvara delivered two records at once, having sailed during migration 10,880 kilometers one way and 22,511 kilometers in total. She crossed the Pacific from Sakhalin to the coast of North America and back, proving that the eastern and western gray whale populations are mixed, and do not exist in isolation, as was previously thought. The study is published in Biology Letters .
Scientists have supplied seven gray whales from the western population with GPS sensors to track their routes during feeding and migration. All whales were marked near the island of Sakhalin. Three of them eventually reached the coast of North America, one of them, a female named Varvara, overcame 10,880 kilometers. Subsequently, she returned to the shores of Sakhalin, and the length of her general route was 22.5 thousand kilometers. Both figures became a record for the range of migration of mammals.During her stay at the coast of North America, Varvara visited places where gray whales from the eastern population reproduce. This fact turned out to be a great news for biologists, as it was previously believed that the western and eastern populations of the Pacific gray whales are kept apart from each other. It is known that the western population of animals is on the verge of extinction due to the whaling of Japan.The authors note that their work raises a number of new questions in the study of gray whales. In particular, two things became clear: firstly, the routes of eastern whales do not obey the old idea of coastal migration from north to south and back. Secondly, in order to assign a whale to a particular population, more precise methods are needed than just the location of its detection.