Gray whales (Cetacea: Eschrichtiidae: Eschrichtius robustus) were once abundant throughout coastal waters of the northern Atlantic and Pacific oceans. Although hunted on a small scale for their oil, meat, and blubber for thousands of years, intensive commercial whaling in the late nineteenth century nearly drove them to extinction. By the early twentieth century the Atlantic population had been extirpated, and the Pacific populations were in sharp decline.
In 1947 the International Whaling Commission (IWC) instituted a ban on the commercial hunting of gray whales. While the “western” Pacific population that inhabits the waters of Asia is still endangered, the “eastern” Pacific population off the west coast of North America has experienced a significant recovery. Today it’s estimated that there are approximately 20,000 individuals in the eastern population.
Adult gray whales can approach 50 feet (15 m) in length and 40 tons (36,000 kg) in weight. Their streamlined bodies are dark gray in color, although by adulthood they’re typically covered with white barnacles and orange whale lice that cling to their skin. The mottled coloration gives adult gray whales a rather unique appearance.
These whales make one of the longest migrations of any mammal, traveling anywhere from 10,000 to 14,000 miles (16,000 to 22,530 km) annually. In summer most members of the eastern population travel north to rich feeding grounds, some as far as the Bering Sea. Here these bottom-feeding animals gorge themselves on small crustaceans, tube worms, and other invertebrates, filtering them from seawater through the baleen that lines their mouths. In autumn most spend two to three months venturing south to protected lagoons on the Mexican coast to breed. Since gestation is around one year in duration, mating and calving both occur in this area. In the spring they head back north, and mothers continue to nurse their calves for up to eight months while ferociously protecting them from orcas, their only natural predator. Historically mothers were also known to fight human whalers with equal violence, earning them the nickname “devilfish.”