The
gray whale (
Eschrichtius robustus) is a
baleen whale that migrates between feeding and breeding grounds yearly. It reaches a length of , a weight of , and lives between 55 and 70 years. The common name of the whale comes from the gray patches and white mottling on its dark skin. Gray whales were once called
devil fish because of their fighting behavior when hunted. The gray whale is the sole living species in the
genus Eschrichtius, which in turn is the sole living genus in the
family Eschrichtiidae. This mammal descended from filter-feeding whales that developed at the beginning of the
Oligocene, over 30 million years ago.