The gray whale historically lived in both the north Pacific and north Atlantic oceans, but now only lives in the Pacific. They live in relatively shallow waters over the continental shelves of western North America and eastern Asia. Interestingly, though gray whales are in fact gray, they were scientifically described by a man named John Edward Gray, so it is possible that the common name is meant to honor him.
Though they are quite large (up to 46 feet/14 m), gray whales feed on small benthic worms and other invertebrates. Through a unique feeding strategy known as suction feeding, gray whales bite off huge mouthfuls of soft sediments (sand or mud) from the seafloor and then constrict the muscles of their mouths and throats to force out the water and sand, filtering out the food with their baleen. This feeding strategy is analogous to the filter feeding of the other large, baleen whales. These whales are known to undergo very long migrations between feeding grounds near the poles and calving grounds in well-protected lagoons in the sub-tropics. Unlike the other great whales, though, gray whales feed along the way.
Like all whales, gray whales are mammals and give live birth to large calves. Because the female is responsible for providing milk for and protecting its babies, she must store extra energy reserves and is consequentially larger than males. All of the record gray whales (by size) are females. Gray whale mothers are known for being particularly protective of their young and have been known to attack boats that threaten their babies. Calves, on the other hand, are quite curious and are known to approach and investigate boats. These differing behaviors can present potential conflict for whale watching operations. The killer whale is the only species known to attack and eat gray whales (always juveniles).
Commercial whaling during the 17th-20th centuries (and perhaps even earlier) had an extremely detrimental affect on gray whale populations. Numbers were reduced so significantly that the north Atlantic population is now extinct, and the north Pacific population nearly went extinct in the 20th century. Fortunately, with complete legal protection in the United States and Mexico, the eastern Pacific Ocean population has recovered to about 20% of its pre-whaling numbers and is now stable. The western Pacific Ocean population is still at risk of extinction and was thought to be lost until being rediscovered in the 1980s. The recovery and continuing protection in the eastern Pacific, however, means that the species as a whole is now considered of least concern. Successful management and careful protection has saved this species from the brink of being lost.