This species is not considered very social, though it is not uncommon to see groups of four or five whales traveling together. During migration, the whales typically travel in groups of two of more individuals. When near the shoreline or boats, gray whales will rise vertically out of the water, just high enough to scan its surroundings. This behavior is called spyhopping and may last as long as 30 seconds. Early whalers called the gray whale the devilfish because females strongly defended their young against all enemies, including orcas, sharks, and humans.
Gray whales reach sexual maturity at eight or nine years.
A female will give birth only once in two years, usually to a single calf after a 12-13 month gestation period. Most gray whales calve in the lagoons of Baja California, and as with all cetaceans , the young are born underwater and are able to swim immediately. The calves depend on a diet of rich milk for at least six months. They are weaned the following summer at seven to eight months, though young whales will often stay with their mothers for an additional one or two years. Gray whales obtain most of their food during the summer months in the Arctic.