North Atlantic right whale

Distribution and Habitat

As its name implies, North Atlantic right whales live within the North Atlantic Ocean. Other species of right whales inhabit different oceans: the North Pacific right whale (Eubalaena japonica) in the North Pacific Ocean and the southern right whale (Eubalaena australis) in the southern oceans. Right whales inhabit both the eastern and western portion of the North Atlantic Ocean, but there are very few remaining in the eastern portion. The western portion of the ocean, along the coast of North America, is home to the majority of the population. This is primarily a coastal species and is not typically encountered far offshore or in very deep water. They may also be found within large bays and estuaries.

Within the western North Atlantic Ocean, right whales feed during spring, summer, and fall in temperate and subpolar latitudes near eastern Canada and the northeastern U.S. During the winter, many individuals from this population can be found off the northeast coast of Florida and Georgia, their breeding and calving grounds. Some right whales, however, may remain at their northern feeding grounds during the winter.

Summer feeding habitat is within cold waters where prey is abundant. This is typically within relatively shallow waters. Winter breeding and calving habitat is within warm shallow waters. Prey is largely absent from these waters and right whales will typically go without any food during the months spent at the breeding grounds. Calving areas are near continental shores.

Diet

Right whales primarily feed on zooplankton, including small crustaceans called copepods and krill. They feed by filter feeding with their mouthful of baleen. They do so by taking a large mouthful of both prey and water, closing their mouth, and then pushing the water out of their mouth using their enormous tongue. The prey items are then left within the mouth, trapped by the strips of baleen, and ready to be swallowed.

Right whales use a feeding technique known as “skimming”. They feed by moving through patches of zooplankton in the water with their mouth open and catching the prey with their baleen.

Life Cycle

During the summer, right whales will spend most of their time feeding and building-up fat in the cold waters of the North Atlantic. These fat stores will be necessary for the long migration to their winter breeding and calving grounds, located in warmer subtropical waters, where no feeding will take place for the entire winter. At their winter breeding and calving grounds, right whales may form small loose groups. These groups usually consist of a single adult female and several adult males.

Adult females give birth to their first calf at an average age of 9-10 years old while at the calving grounds during the winter, after a pregnancy which lasts for one year. Females will only become pregnant every three to five years. A mother and calf will form a very close attachment to each other and the calf will feed on the mother’s milk for up to one year after birth. Males play no role in raising their young.

Right whales may live for at least 50 years, but there is little data regarding longevity. Closely related species are thought to live for over 100 years. Their only known predator, besides humans, is the killer whale (Orchinus orca).