Western gray whales were sighted seven years ago to monitor migration . The then eight - year - old female called Varvara swam from Russia to breeding grounds near Mexico during five - and - a - half years in captivity . Gray whales typically do n't eat during migration , which has led some to believe she did n't eat during the long journey . Previous migration was held by a humpback who swam 11,706 miles in 2011 .
Western gray whales were tagged seven years ago to monitor migration . The then nine-year-old female called Varvara swam from Russia to breeding grounds near Mexico during five-and-a-half months in 2011 . Gray whales typically do n't feed during migration , which has led researchers to believe she did n't eat during the long journey . Previous record was held by a humpback who swam 11,706 miles in 2011 .