The gray whale has a relatively small, narrow head, which arches distinctively between its blowhole and snout. The baleen plates are about 50cm long. It has grey skin, which can be slate-blue or marbled white; small yellow parasitic crustaceans on its skin, and often as much as 100 - 200kg of barnacles and whale lice attached to the head and body. Young gray whales are darker and have fewer barnacles and white marks. The gray whale has a robust body and flippers which are small and paddle-shaped. Instead of a dorsal fin there is a low hump with ‘knuckles' between the hump and the tail. This whale's appearance and behaviour make it difficult to mistake for another species in the wild.
Gray whales are the most coastal of the large whales, rarely venturing more than 20 – 30kms offshore and has for this reason become one of the world's most watched whales. They are also well known for performing one of the world's longest migrations, making a yearly round trip of 15,000-20,000 km. In the past there have been three populations of gray whale. The North Atlantic population became extinct in the 17th -18th centuries for reasons that are not clear, but their bones are still occasionally uncovered by the wind on the sandy coastal beaches of North Carolina. There is a tiny remnant population in the western North Pacific of no more than 130 individuals. They are known to use feeding grounds off Sakhalin Island, Russia. Today, the main population is in the eastern North Pacific, which was reduced to a few hundred individuals by the early 1900s. Protection has however led to an increase in numbers and the population is considered to be recovering.
Gray whales are active, inquisitive and friendly, often approaching boats. They show a range of surface behaviours, including spyhopping, lobtailing and breaching. They can also be seen surf-riding in very shallow waters. Gray whales are bottom feeders; they hunt seabed creatures by rolling over on one side then swimming slowly along sucking up sediment and the small creatures that live in it. They then sieve out the water and silt through their baleen, trapping the food behind. Most gray whales turn on their right side to feed, but like humans some are 'left-handed'. Because of this, the baleen on the right side is usually shorter and more worn than the baleen on the left side, and the right side of the head is more scarred from rooting around on the bottom. A typical group size is only 1 - 3 individuals. Gray whales are usually gentle creatures but gained a reputation as ‘devil fish' for allegedly attacking the boats of those hunting them, which may have been partly due to defence of their young. Gray whales can live up to 70 years old.
Over a lifetime, a gray whale migrates the equivalent distance of a return trip to the moon. Gray whales are now only found in the North Pacific and adjacent waters. The larger eastern North Pacific population summers and feeds mainly in the shallow waters of the Chukchi and Beaufort seas, and the northwestern Bering Sea; a few also summer and feed along the Pacific coast from Vancouver Island (Canada) to central California (US). The population migrates in autumn along the coast to winter breeding grounds on the west coast of Baja California (Mexico) and the southeastern Gulf of California. The much smaller western subpopulation summers in the Okhotsk Sea. The major known feeding grounds are off the northeastern coast of Sakhalin Island (Russian Federation), but some animals are occasionally seen off the eastern coast of Kamchatka (Russian Federation) and in other coastal waters of the northern Okhotsk Sea. This population's migration route is not well known. The species is listed as Least Concern by IUCN, whilst the western North Pacific stock is listed as Critically Endangered. Pollution, prey depletion and, in recent years, the resumption of a small scale hunt by the Makah Tribe off Washington State, impact the eastern North Pacific population today, as well as habitat loss, human disturbance and entanglement in fishing nets. The western North Pacific population is under threat from large-scale oil and gas exploration and extraction on its feeding grounds, in addition to chemical pollution, incidental entanglement in fishing nets and vessel collisions.