The North Atlantic Right Whale is a baleen whale, one of three right whale species belonging to the genus Eubalaena, formerly classified as a single species. With only 400 in existence, North Atlantic right whales are among the most endangered whales in the world. They are protected under the U.S. Endangered Species Act of 1973 and the Marine Mammal Protection Act of 1972. Vessel strikes and entanglement in fixed fishing gear are the two greatest threats to their recovery.
More than four hundred and fifty right whales live in the North Atlantic Ocean. They migrate between feeding grounds in the Gulf of Maine and their winter calving areas off Georgia and Florida, an ocean area with heavy shipping traffic.
Like other right whales, the North Atlantic right whale, also known as the northern right whale or black right whale, is readily distinguished from other whales by the callosities on its head, a broad back without a dorsal fin, and a long arching mouth that begins above the eye. The body of the whale is very dark grey or black, occasionally with white patches on the belly. The right whale's callosities appear white due to large colonies of cyamids or whale lice.
Adult North Atlantic right whales average 13–16 m (43–52 ft) in length and weigh approximately 40,000 to 70,000 kg (44 to 77 short tons), they are slightly smaller on average than the North Pacific species. The largest measured specimens have been 18.2 m (60 ft) long and 106,000 kg (230,000 lb). Females are larger than males.
Forty percent of a right whale's body weight is blubber, which is of relatively low density. Consequently, unlike many other species of whale, dead right whales float.
There is little data on their life span, but it is believed to be at least fifty years, and some may live more than a century.
Right whales feed mainly on copepods and other small invertebrates such as krill, pteropods, and larval barnacles, generally by slowly skimming through patches of concentrated prey at or below the ocean surface.