Northern right whale, Black right whale
The North Atlantic right whale (Eubalaena glacialis) is a rare 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, 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.
The North Atlantic 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 a v-shaped blowhole which produces a heart-shaped blow. The most distinguishing feature of 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. Callosities are not caused by the external environment and are present in 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 a measure of individual health in visual health assessments. 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 low density of blubber. Females of this species are larger than males.
North Atlantic right whales inhabit the western North Atlantic, from Nova Scotia to Florida. They migrate from a calving ground near Florida and Georgia on North America's eastern seaboard to summering grounds in the Bay of Fundy, the Gulf of Maine, and the Scotian Shelf, with some animals going as far as the Gulf of St Lawrence, the Denmark and Davis Straits and sometimes Iceland and Norway. The species migrates between two essential habitats: calving grounds and feeding grounds, the latter in the north of the range and the former in the warmer waters of the south of the range, in bays or shallow coastal waters.
These whales generally travel solo or with a small group. The usual group size ranges from two to 12 but is usually two. The composition of the group varies from female-calf, males only, or mixed. Group size is difficult to determine because of the dispersion. Larger groups may exist over long distances by staying in contact with echolocation. These whales are quite social and swim alongside other species of cetaceans. Social groups can moan and bellow at night to each other around breeding areas. Females will sometimes swim while on their backs, cradling a newborn calf on their bellies in their huge flippers. The North Atlantic right whale will make a series of brief shallow dives before diving underwater for as long as 20 minutes.
North Atlantic right whales are carnivores (planktivores). They 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.
These whales are polyandrous, with females mating with many males. No aggression is seen between competing males, a rare behavior for mammals. A North Atlantic right whale mates in the winter. Gestation lasts 12-13 months, with females giving birth to a single calf. Every three to four years they give birth to one calf. The mother and her calf remain close together until around the age of one when the calf is weaned. During the first year, the calf learns from its mother where the critical feeding grounds are, and it will visit them for the rest of its life. North Atlantic right whales are sexually mature between 8 – 11 years old.
This species is threatened by being separated from calving areas due to shipping traffic, ship collisions, and by becoming tangled in fishing nets, entanglement sometimes causing serious injury or death because fishing gear can wrap around the whale’s mouth and stop it from feeding or cause it to drown because it cannot surface for air. Oceans warming up can impact the food sources of whales. Extensive patches of minute animals and plants that they eat will likely change in abundance or move elsewhere as seawater temperature, ocean currents, and winds alter due to climate change. The shift in the availability of food has already damaged the reproductive rates of this endangered whale.
According to the IUCN Red List, the total population size of the North Atlantic right whale at the end of 2018 was 409 individuals, of which 200-250 were mature. Currently, this species is classified as Endangered (EN), and its numbers today are decreasing.
