Right whales primarily feed upon zooplankton, a type of plankton consisting of mostly microscopic live animals. These include tiny crustaceans such as copepods and krill; pteropoda; free-swimming sea slugs and sea snails; and cyprid, which are the mobile larvae of barnacles.
Right whales feed by skimming. They swim with their mouth open through a field of zooplankton and then expel the water. The baleen plates that they have instead of teeth filter and retain the prey while allowing the water to escape. They may feed at the surface, underwater or even at the bottom of the ocean. Most right whales feed only from spring until fall, though some also feed in the winter.
The three species of right whale include the North Atlantic right whale, the North Pacific right whale and the southern right whale. In addition, the bowhead whale is also referred to as the Greenland right whale. They generally inhabit coastal areas in temperate and sub-polar waters. Southern right whales are much more abundant than the two northern species. In the United States, both species of northern right whales are protected by the Endangered Species Act. In particular, as of 2014, the right whale populations in the North Pacific and North Atlantic are listed as endangered on the IUCN Red List of Endangered Species.