Right whales are baleen whales belonging to the family Balaenidae. There are four species in two genera: Eubalaena (three species) and Balaena (one species, the Bowhead Whale, also called the Greenland Right Whale).
Right whales can grow to 60 ft long and weigh up to 100 metric tons. Their bodies are mostly black, with distinctive white Calluses (skin abrasions) on their heads. They are called “right whales” because whalers thought the whales were the “right” ones to catch. The Right Whale Population was reduced by hunting during the active years of the whaling industry. Nowadays, instead of hunting them, people often watch this acrobatic family for pleasure. The three right whale species live in geographically distinct locations. Around 300 Atlantic Northern Right Whales live in the North Atlantic, while the North Pacific has approximately 200 Pacific Northern Right Whales. Finally, about 7,500 Southern Right Whales are spread throughout the southern part of the Southern Hemisphere.
After many years of shifting views on the number of right whale species, recent genetic evidence has led scientists in the field to conclude that there are in fact four distinct species.
In dealing with the three populations of Eubalaena right whales, authorities have historically disagreed over whether to categorize the three populations in one, two or three species. In the whaling days there was thought to be a single worldwide species. Later, differences in the skull shape of northern and southern animals lent support to the view that there were at least two species””one found only in the northern hemisphere, the other found in the Southern Ocean.
Right whales are easily distinguished from other whales by the large number of calluses on their heads, a thick back without a dorsal fin, and a long drooping mouth that begins high above the eye and then arches round beneath it. The body of the whale is very dark grey or black with some white patches on the belly. The white patches on the whale’s skin around the calluses are not due to skin pigmentation, but are actually large colonies of whale lice buried in the whale’s skin.
Adults average between 36″“59 ft in length and typically weigh 60 to 80 tones. The most typical lengths are 13″“16 m. The body is extremely robust with girth as much as 60% of total body length in some cases. The tail fluke is also broad (up to 40% of body length). The North Pacific species is on average the largest of the three. The largest specimens of these may weigh 100″“tons.
The testicles of the right whale are likely to be the largest of any animal, each weighing around 500 kg. At 1% of the whale’s total body weight, this size is very large even taking into account the size of the whale. Right whales have a distinctive wide V-shaped blow, caused by the widely-spaced blowholes on the top of the head. The blow rises to 5 m above the ocean’s surface.
Females reach sexual maturity at 6″“12 years and breed every 3″“5 years. Both reproduction and calving take place during the winter months. Calves are approximately 1 ton in weight and 4 – 6 m in length at birth following a gestation period of 1 year. The right whale grows rapidly in its first year, typically doubling in length. Very little is known about the life span of right whales. One of the few pieces of evidence is the case of a mother Atlantic Northern Right Whale that was photographed with a baby in 1935, then photographed again in 1959, 1980, 1985 and 1992, with callosity patterns being used to ensure it was the same animal. Finally, she was photographed in 1995 with a seemingly fatal head wound that is presumed to have been caused by a ship strike. The animal was around 70 years of age at death. Research on Bowhead Whales suggests reaching this age is not uncommon and may even be exceeded.
Right whales are slow swimmers, reaching only 5 knots (9 km/h) at top speed, but are highly acrobatic and frequently lunge. Like other baleen whales, the species is not gregarious and the typical group size is only two. Larger groups of up to twelve have been reported, but these were not close-knit and may have been transitory.
The right whale’s only predators are the killer whale and, to some degree, humans. When danger lurks, a group of right whales may come together in a circle, with their tails pointing outwards, in order to deter the predator. This defense is not always successful and calves are occasionally separated from their mother and killed.
The right whales’ diet consists primarily of zooplankton and tiny crustaceans such as copepods, as well as krill, and pteropods. They feed by “skimming” along with their mouth open. Water and prey enters the mouth but only the water can pass through the baleen and out again into the open sea. The “skimming” may take place on the surface (where it can be spectacular to watch), underwater or even close to the ocean’s bottom, indicated by mud occasionally observed on right whales’ bodies.
Sound production and hearing
Vocalizations made by right whales are not elaborate compared to those made by other whale species. The whales do make groans, pops and belches. The purpose of the sounds is not known but is likely to be a form of communication between whales within the same group.
Population and distribution today
Today, the three right whale species inhabit three distinct areas of the globe, the Atlantic Northern in the western Atlantic Ocean, the Pacific Northern in a band from Japan to Alaska and the Southern in all areas of the Southern Ocean. The whales can only cope with the moderate temperatures between 20 and 60 degrees in latitude. The warm waters of the equator region form a barrier and prevent the northern and southern groups from inter-mixing. Although the Southern species in particular must travel across open ocean to reach its feeding grounds. In general, they prefer to stay close to peninsulas and bays and on continental shelves, as these areas offer greater shelter and abundance of their preferred food.
There are about 300 Atlantic Northern Right Whales, almost all living in the western North Atlantic. In spring, summer and autumn, they feed in areas off the Canadian and north-east US coasts in a range stretching from North Carolina to Nova Scotia. Particularly popular areas appear to be the Bay of Fundy and Grand Manan Island. In winter, they head south towards Georgia and Florida in order to mate and, a year later, give birth.
Only about 200 North Pacific right whales survive. Thus, the two northern right whale species are the most endangered of all large whales and two of the most endangered animals in the world. Based on current population density trends, both species are predicted to become extinct within 200 years. The Pacific species was historically found from the southern tip of Japan, across the Bering Strait and down the North American coast as far as California.
The leading cause of death among Atlantic Northern Right Whales, which migrate through some of the world’s busiest, shipping lanes whilst journeying off the east coast of the United States, is injuries sustained from colliding with ships. At least 16 reported deaths due to ship strikes were reported between 1970 and 1999, and probably many more remain unreported. Recognizing that this toll could tip the balance of the already delicately poised species towards extinction, the United States government introduced measures to curb the decline.