The North Atlantic right whale (Eubalaena glacialis) is a baleen whale, one of three right whale species belonging to the genus Eubalaena, all of which were formerly classified as a single species. Because of their docile nature, their slow surface-skimming feeding behaviors, their tendencies to stay close to the coast, and their high blubber content (which makes them float when they are killed, and which produces high yields of whale oil), right whales were once a preferred target for whalers. At present, they are among the most endangered whales in the world, and they are protected under the U.S. Endangered Species Act and Marine Mammal Protection Act and Canada's Species at Risk Act. There are an estimated 356 individuals in existence in the western North Atlantic Ocean—they migrate between feeding grounds in the Labrador Sea and their winter calving areas off Georgia and Florida, an ocean area with heavy shipping traffic. In the eastern North Atlantic, on the other hand—with a total population reaching into the low teens at most—scientists believe that they may already be functionally extinct. Vessel strikes and entanglement in fixed fishing gear, which together account for nearly half of all North Atlantic right whale mortality since 1970, are their two greatest threats to recovery.
Description
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 cetaceans by the absence of a dorsal fin on its broad back, short, paddle-like pectoral flippers and a long arching mouth that begins above the eye. Its coloration is dark grey to black, with some individuals occasionally having white patches on their stomachs or throats. Other unique features include a large head, which makes up a quarter of its total body length, narrow tail stock in comparison to its wide fluke, and v-shaped blowhole which produces a heart-shaped blow. The most distinguishing feature for right whales is their callosities: rough, white patches of keratinized skin found on their heads. The right whale's callosities provide habitat for large colonies of cyamids or whale lice, which feed on the right whale's skin as these small crustaceans cannot survive in open water. The relationship between cyamids and right whales is symbiotic in nature but is poorly understood by scientists. Callosities are not caused by the external environment and are present on fetuses before birth. However, Cyamids near the blowhole have been linked to chronic entanglement and other injuries; their presence in this area has been used as measure of individual health in visual health assessments. Adult North Atlantic right whales average 13–18 m (43–59 ft) in length and weigh approximately 40,000 to 90,000 kg (44 to 99 short tons), they are slightly smaller on average than the North Pacific species. On each side of the upper jaw are 200–270 baleen plates. These are narrow and approximately 3 m (9.8 ft) long, and are covered in very thin hairs. The pectoral fin is 1.7 m (5.6 ft) long. The largest measured specimens have been 18.5 m (61 ft) long and 106,000–108,000 kg (234,000–238,000 lb). Females are larger than males. Up to forty-five percent of a right whale's body weight is blubber. This high percentage causes their body to float after death due to the fact that blubber has a low density. There is little data on their lifespan but it is believed to be at least 70 years, although individuals in species closely related to right whales have been found to live more than 100 years. Currently, female North Atlantic Right whales live on average 45 years and males 65 years. Age of right whales can be determined by examining their earwax postmortem. The oldest recorded whale was sighted between March 24, 1935 and August 13, 1995, and is thought to have been as old as 70 years. However, a 2024 study found that the average lifespan was only 22 years, with only 10% of individuals living longer than 47 years, presumably as a result of shortened lifespans due to commercial whaling.
Behavior
Surface activities
Aside from mating activities performed by groups of single female and several males, so called SAG (Surface Active Group), North Atlantic right whales seem less active compared to subspecies in southern hemisphere. However, this could be due to intense difference in number of surviving individuals, especially calves that tend to be more curious and playful than adults, and small amount of observations. They are also known to interact with other baleen whales especially with humpback whales or bottlenose dolphins.
Vocalization North Atlantic right whales recordings are available online. Many effective automated methods, such as signal processing, data mining, and machine learning techniques are used to detect and classify their calls.
Reproduction North Atlantic right whales are promiscuous breeders. They first give birth at age nine or ten after a year-long gestation; the interval between births seems to have increased since the 1990s, and now averages three to six years. Calves are 13–15 feet (4.0–4.6 m) long at birth and weigh approximately 3,000 pounds (1,400 kg). The North Atlantic right whale's penis can reach at least 1.8 m (5 ft 11 in) in length.
Predation The only known predator of the North Atlantic right whale is the killer whale. There is one recorded case of predation.
Feeding 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. Sei whales and basking sharks (sometimes minke whales as well) are in positions as food competitors and are known to feed in the same areas, swimming next to each other, but there have not been any conflicts observed between these species.
Taxonomy
The whale's scientific name is Eubalaena glacialis, which means "good, or true, whale of the ice". The cladogram is a tool for visualizing and comparing the evolutionary relationships between taxa. The point where a node branches off is analogous to an evolutionary branching – the diagram can be read left-to-right, much like a timeline. The following cladogram of the family Balaenidae serves to illustrate the current scientific consensus as to the relationships between the North Atlantic right whale and the other members of its family.
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