Right whales and bowhead whales

(Balaenidae)

Class Mammalia

Order Cetacea

Suborder Mysticeti

Family Balaenidae

Thumbnail description
Large, mainly black, baleen whales with proportionally large heads, narrow rostra, strongly arched mouthlines, broad flippers, and no dorsal fins

Size
43–65 ft (13–20 m); 168,000–224,000 lb (76,200–101,600 kg)

Number of genera, species
2 genera; 4 species

Habitat
Marine, coastal, pelagic, shallow, and deep waters

Conservation status
Endangered: 1 species; Lower Risk/Conservation Dependent: 2 species

Distribution
Arctic and subarctic (bowhead), temperate Northern and Southern Hemispheres, with movement into Antarctic and subarctic waters in summer (right whales); largely absent from tropical belt

Evolution and systematics

The balaenids diverged from the other mysticetes relatively early, possibly around 30 million years ago (mya). The oldest fossil is Morenocetus parvus, a primitive balaenid from the early Miocene of Argentina (23 mya). Numerous fossils of more derived balaenids have been reported from deposits of late Miocene and Pliocene ages, especially in Europe. In fact, species in the extinct genus Balaenula have more highly derived crania than either of the living genera.

Balaena was the only genus in the suborder Mysticeti recognized by Linnaeus, and early classification systems generally placed all baleen whales within it. For more than 100 years, however, there has been a firm consensus that bowhead and right whales belong to a separate family of mysticetes, the Balaenidae. The pygmy right whale (Caperea marginata) was assigned to a family of its own, Neobalaenidae, in the 1920s.

There has been considerable disagreement until recently about whether bowheads and right whales should be assigned to one genus, Balaena, or instead the right whales should be in a separate genus, Eubalaena. In addition, there has been difficulty agreeing on the number of right whale species. Two had long been recognized: southern, Eubalaena australis, and northern, E. glacialis. Current convention is to recognize two genera, one containing only B. mysticetus, or the bowhead whale; the other containing three species of right whales: North Atlantic, E. glacialis, North Pacific, E. japonica, and southern, E. australis, although there is some debate on whether E. japonica is a separate species.

Referring to the balaenids generically as right whales causes some confusion. As recently as the nineteenth century, whalemen and scientists referred to the bowhead as the Greenland or Arctic right whale, and to the other species in the family as black right whales. Given the difficulties, it seems more appropriate, or at least less confusing, to refer to the family as a whole as balaenids, and to reserve the term "right whales" for the genus Eubalaena.

Physical characteristics

The most obvious distinguishing characteristics of the family Balaenidae are the large head (up to one third of the total body length), the narrow, arched rostrum, the complete absence of a dorsal fin, and the broad flippers. The body is rotund, and the mouth-line greatly arched to accommodate long baleen plates (to 9 ft [2.8 m] in right whales, 13 ft [4 m] in bowheads) that hang from the roof of the mouth. There is a space at the front of the upper jaw separating the rows of baleen plates into a left and a right series. The blows of bowheads and right whales are more consistently V-shaped than those of other whales.

The body color is basically black. Bowheads have a white chin patch and a light gray-to-white band around the base of the tail, sometimes extending onto the flukes. Right whales often have irregular white ventral patches.

The most conspicuous difference in appearance between bowheads and right whales is that the latter have callosities

on their heads, especially on the rostrum, lower lips, and chin, and above the eyes. These irregular, thickened patches of hard skin are colonized by small amphipod crustaceans, called cyamids, or "whale lice." The skin of both bowhead and right whales is generally free of barnacle infestation, although the callosities of southern right whales are colonized by the barnacle genus Tubicinella.

Distribution

Balaenids have a nearly cosmopolitan distribution in marine waters, or at least they did before being drastically depleted by commercial whaling. They are absent only between the tropics of Cancer and Capricorn and in the far southern reaches of the Antarctic. The only large marine area poleward of 30° of latitude where they are not known ever to have been common is the Mediterranean Sea, although there have been a few records there. Bowheads occurred historically throughout the Arctic, including the Sea of Okhotsk, Hudson Bay, and Gulf of St. Lawrence. Ice massifs along the northern coasts of Asia and North America periodically blocked their passage between ocean basins.

Right whales were widely distributed across the North Atlantic and North Pacific north of 30°N, but are now almost entirely absent in the eastern portions of those basins. In the Southern Hemisphere, right whales occur in summer throughout most of the sub-Antarctic zone between 35–40°S and 55–60°S. Their wintering grounds are centered in discrete areas of coastline along the South American, African, and Australian continents as well as around certain oceanic islands, including St. Paul and Tristan da Cunha.

Habitat

The defining characteristic of balaenid feeding habitat is zooplankton productivity, as these filter-feeding whales need very high-density concentrations of prey on which to forage efficiently. Thus, their summer distribution centers on coastal and offshore areas where physical processes, involving bottom topography, water column structure, and currents, aggregate plankton.

All balaenid populations appear to have large ranges and to migrate over fairly long distances. Bowheads are exceptionally adapted to coping with the annual formation and disintegration of sea ice in high latitudes. They travel through areas where cracks and pools of open water are widely and irregularly spaced, and they can break through new ice 9 in (22 cm) thick.

Known right whale calving grounds tend to be in warm temperate bays and shallow coastal regions. While such areas have been identified in the North Atlantic and Southern Hemisphere, none have been specifically located for North Pacific right whales or bowheads.

Behavior

The slow swimming speeds of balaenids made them vulnerable to capture by early whalers who could approach in small open boats powered by hand or sail. They were, nevertheless, dangerous quarry because of their powerful tails.

Numerous whaleboats were "stove," that is, broken and splintered by the thrashing tail of a harpooned bowhead or right whale. The tail is also used to defend against attempts at predation by killer whales (Orcinus orca). Besides fighting back, bowheads move into heavy ice to elude killer whales. The general distribution and migration patterns of bowheads may have been strongly influenced, via selection pressure, by the need to reduce frequency of encounters with killer whales.

These whales typically raise their flukes above the surface at the beginning of a long dive. They probably do not dive deeper than a few hundred feet (meters), and most dives do not last longer than 10–20 minutes. Bowheads under duress (e.g., when harpooned, or perhaps when transiting long distances under solid ice) can remain submerged for much longer, possibly up to an hour.

Balaenids are fairly vocal, producing low-frequency moans, grunts, belches, and pulses. Some bowhead calls have been described as growls, roars, trumpet sounds, or wild complex screams. They occasionally make high-frequency whines or squeals. During spring, bowheads produce songs that typically consist of one to three themes, composed of one- to five-note phrases. These songs are believed to serve a reproductive function, perhaps to attract females or dominate rival males. Loud, sharp sounds reminiscent of gunshots are sometimes heard from southern right whales and bowheads. It has been suggested that reverberations from their calls are used by bowheads to sense the undersides of ice floes and thereby navigate under sea ice.

Feeding ecology and diet

Balaenids prey exclusively on zooplankton, mainly copepods and euphausiids. Their long, finely fringed baleen and capacious mouths are well adapted to filter huge quantities of very small organisms. As skim-feeders, they swim forward with the mouth open, allowing water to flow in through the front of the mouth and pass out through the baleen filter, trapping food organisms on the inside fringed surfaces. The prey are then swept off the baleen and into a narrow digestive tract by the massive tongue.

Reproductive biology

Like other cetaceans, balaenids give birth to single young. Gestation takes at least a year and calves are nursed for six months or longer. The inter-birth interval is generally three years for prime-aged females, and probably increases as they approach senescence. Female right whales generally do not

give birth to their first calf until they are eight or nine years old. One photo-identified individual gave birth to seven calves over a 29-year period. While right whales are known to be capable of living for close to 70 years, bowheads live even longer, and thought to reach ages of well over 100.

Right whales have the largest testes of any animal (6 ft [2 m] long and nearly 2,000 lb [900 kg]). It is therefore assumed that sperm competition is a central feature of their reproductive strategy. There is no evidence to suggest long-term pairing between males and females. The mating system is polygamous, with multiple males engaging in what behaviorists call "scramble competition" for opportunities to copulate with a focal female.

Conservation status

All balaenids have been legally protected from commercial whaling since the 1930s, but aboriginal people in the Arctic are exempted and continue to hunt bowheads. Most ongoing whaling is subject to management by the International Whaling Commission (IWC) in cooperation with national and local authorities, and the limits on removals appear adequate to ensure continued population recovery. The hunting in eastern Canada, however, takes place outside the IWC's purview, and there is no assurance that the populations hunted there will be allowed to recover. Although the bowhead is still reasonably abundant in the western Arctic, its numbers in the eastern Arctic are much less than 5% of what they were when commercial whaling began.

Several populations of southern right whales are making strong recoveries from the depletion caused by commercial whaling, but aggregate abundance is still only about 10% of what it was in the late sixteenth century. The situation is much less hopeful in the Northern Hemisphere. A few hundred right whales remain in the western portions of the North Pacific and North Atlantic, but the populations on the east sides of these basins are all but extirpated, consisting of only scattered individuals and small groups. Even with best-case reasoning, one cannot escape the fact that there are less than 5% as many Northern Hemisphere right whales alive today than there were when commercial whaling began.

The clearest threat to right whales today is incidental mortality, caused mainly by collisions with ships and by entanglements in fishing gear such as set or drifting gillnets and lines connecting surface buoys with bottom traps for crustaceans (crabs, lobsters, etc.). There is also uncertainty whether some very small populations, such as bowheads around Svalbard and right whales in the eastern North Pacific and eastern North Atlantic, have the intrinsic capacity to recover, given their loss of genetic and demographic diversity, changes in their ecological circumstances, and the possibility

that they or their prey are being affected by chemical pollution.

The IUCN lists the bowhead and one of its populations as Lower Risk/Conservation Dependent, one of its populations as Critically Endangered, two as Endangered, and one as Vulnerable. The southern right whale is listed as Lower Risk/Conservation Dependent and the northern right whale and its populations are listed as Endangered.

Significance to humans

Northern people traditionally used bowhead baleen to construct toboggans, baskets, and traps and snares for catching birds and mammals. They also depended on bowheads for food, for oil to produce light and heat, and for construction materials. Bowhead bones supported the walls and roofs of ancient Thule-culture dwellings across the Arctic. In the present day, Eskimos in Alaska continue to organize much of their cultural life around the annual bowhead hunt, and bowhead meat and blubber remain staples in their diet.

Right whales and bowheads were the chief targets of early Basque, and eventually other European and American whalers. The tough, flexible baleen, known to whalemen as whalebone or bone, had great commercial value. It was used as a stiffener for hoop skirts, shirt collars, and corsets, and to make horse whips and umbrella ribs. Brooms and brushes were fashioned from the fibrous fringes. Discovery of spring steel, and later plastics, obviated the need for baleen, which was, in any event, in short supply by the end of the nineteenth century due to the depletion of balaenid stocks. The blubber oil of right whales and bowheads lighted streets and homes in Europe and North America, and its value did not decline significantly until the advent of electricity and petroleum in modern times.

Today, right whales are the focus of intensive research in North and South America, South Africa, Australia, and New Zealand. Special legislation exists to ensure their protection, and regulations have been implemented to prevent ship strikes and entanglements, especially off the eastern United States and Canada. The accessibility of right whales near shore during winter makes them popular tourist attractions in South Africa, Argentina, and Australia, and their summer presence in eastern Canada's Bay of Fundy supports a number of local tour enterprises.

Species accounts

List of Species

Bowhead whale

Balaena mysticetus

taxonomy

Balaena mysticetus Linnaeus, 1758, Greenland Sea.

other common names

French: Baleine du Groenland; German: Grönlandwal; Spanish: Ballena polar, ballena de Groenlandia.

physical characteristics

Length 46–65 ft (14–20 m); weight 168,000–224,000 lb (76,200–101,600 kg). Rotund shape, but with a distinct "neck" region. No dorsal fin or ridge, very broad back. Flippers have blunt tips and flukes wide with smooth contours. Muscular bulge (the stack) in the blowhole area. Predominantly black; a white patch at the front of the lower jaw may have several dark gray to black spots indicating chin hair. Light gray to white band around tail stock, just in front of the flukes. 250 to 350 baleen plates in each side of the jaw up to 17 ft (5.2 m) long, longest of all whales.

distribution

Arctic circumpolar; largely separate populations (stocks) centered in Sea of Okhotsk, Bering-Chukchi-Beaufort Seas, Hudson Bay-Foxe Basin, Davis Strait, Baffin Bay, and Greenland-Barents Seas; waters bordering northern Russia, United States (Alaska), northern Canada, Greenland, and Norway (Svalbard).

habitat

Marine waters of any depth in high northern latitudes, often associated with pack ice, including very dense (greater than 90%) ice coverage, but also found in open water during summer.

behavior

Strongly migratory in response to ice formation and disintegration; slow-swimming; generally found alone or in small groups that converge on feeding areas and when several males are attempting to mate with a female.

feeding ecology and diet

Forage at surface, in water column, and on sea floor; 60 different species have been identified in stomach contents; copepods and euphausiids are preferred prey; mysids and gammarid amphipods also eaten.

reproductive biology

Mating season late winter and spring, calving season spring or early summer, gestation 13–14 months, lactation less than a year. Single calves are born at intervals of three to four years. Females believed to reach sexual maturity at roughly 15 years of age.

conservation status

About 10,000 bowheads still exist, most in the western Arctic population. Numbers in the other stocks are in the hundreds or less. The once large (25,000) Svalbard stock may number only tens and is considered Critically Endangered. There is concern that habitat deterioration caused by climate change in the Arctic will impair recovery. Also, resumed hunting by Inuit in eastern

Canada is controversial because bowhead numbers there are a small fraction of what they were historically.

significance to humans

Hunting of bowheads probably influenced early human settlement patterns and was a major impetus for Arctic exploration. European countries competed for ascendancy on the Spitsbergen and Davis Strait grounds, while the American fleet dominated in Hudson Bay and the western Arctic. The species continues to be a cultural icon in some Arctic communities with a whaling tradition, and contributes to the Eskimo diet in Alaska and, to a much smaller degree, in Russia and Canada.

North Atlantic right whale

Eubalaena glacialis

taxonomy

Eubalaena glacialis (Müller, 1776), North Cape, Norway.

other common names

French: Baleine de Biscaye; German: Nordkaper; Spanish: Ballena franca del Atlántico Norte.

physical characteristics

Length 43–53 ft (13–16 m); weight 200,000 lb (90,000 kg). One of the stockiest of all whales. Flippers are broad and tend to be more fan-shaped than for most other cetaceans. No dorsal fin or ridge on the broad back. Flukes are very wide and smoothly tapered, with a smooth trailing edge and a deep notch. Most predominantly black, but large white splotches on the belly and chin may be present. Head is covered with areas of roughened skin (callosities) to which whale lice and sometimes barnacles attach, the largest of which is called the bonnet. 200 to 270 baleen plates up to nearly 10 ft (3 m) long.

distribution

Originally across rim of North Atlantic from Florida in west to northwestern Africa in east, with large numbers on feeding grounds in Gulf of Maine, Gulf of St. Lawrence, off southeastern Greenland, Iceland, and northwestern Europe. Presently seen regularly only off eastern North America in coastal waters from northern Florida to Nova Scotia.

habitat

Shallow coastal waters in low latitudes used for calving and nursing in winter months; migratory routes partly coastal but individuals travel long distances offshore as well; summer feeding habitat in cooler northern waters with dense plankton concentrations.

behavior

Courtship groups can involve more than 20 males boisterously competing for access to an adult female, amid much pushing, nudging, and rolling at the surface. In resting state, whales log at surface for long periods, broad backs exposed. Feeding dives last 10–20 minutes.

feeding ecology and diet

Large calanoid copepods are primary prey; also eat smaller copepods, euphausiids, pteropods, barnacle larvae, and salps. Mouth open and baleen visible while surface skim-feeding. Mud on head after surfacing from extended dive implies foraging near sea bottom in some instances.

reproductive biology

Females occasionally bear first calf at five years of age, but average closer to nine to 10 years. Most calves born in winter, weaned by about one year of age. Normal calving interval about three years, but this has been increasing, which raises concern about possible reproductive dysfunction in this population.

conservation status

Endangered. Only about 300–350 survive, compared with many thousands, and possibly tens of thousands historically. High incidence of ship strikes and entanglement in fishing gear along east coast of North America is preventing recovery. Other concerns include chemical pollution and genetic or demographic effects of small population size.

significance to humans

Basque and possibly Norse whalers began whaling for this species about a thousand years ago. Oil and baleen (whalebone) from these whales were valuable commodities, and shore whalers in New York and North Carolina continued to hunt them until the early twentieth century. Given its low numbers and lack of recovery, the small remnant population in the western North Atlantic now commands multi-million dollar annual investments by government agencies and conservation groups. Right whales support economically significant whale-watching in Nova Scotia and New Brunswick, eastern Canada.

North Pacific right whale

Eubalaena japonica

taxonomy

Eubalaena japonica Lacépède, 1818, Japan.

other common names

French: Baleine japonaise; German: Pazifischer Nordkaper; Spanish: Ballena franca del Pacífico Norte.

physical characteristics

Length 46–59 ft (14–18 m); weight 220,000 lb (100,000 kg). One of the stockiest of all whales. Flippers are broad and tend to be more fan-shaped than for most other cetaceans. No dorsal fin or ridge on the broad back. Flukes are very wide and smoothly tapered, with a smooth trailing edge and a deep notch. Most predominantly black, but large white splotches on the belly and chin may be present. Head is covered with areas of roughened skin (callosities) to which whale lice and sometimes barnacles attach, the largest of which is called the bonnet. 200 to 270 baleen plates up to nearly 10 ft (3 m) long.

distribution

Throughout temperate and subarctic North Pacific; to central Bering Sea in north, to Baja California (Mexico) in east, to Taiwan and Bonin (Ogasawara) Islands (Japan) in west, occasionally south to Hawaiian Islands in central Pacific. Most sightings in recent years have been in southeastern Bering Sea (outer Bristol Bay) and southern Okhotsk Sea.

habitat

Unlike for other species of Eubalaena, specific near-shore calving areas have not been identified. General distribution appears to extend all across North Pacific basin, with major feeding areas (at least historically) in Gulf of Alaska, Bristol Bay, southern

Okhotsk Sea, and around Aleutian and Commander Islands.

behavior

Similar to other right whales. The few recent observations have been of small groups and lone individuals, the latter sometimes associated with humpback whales.

feeding ecology and diet

Diet dominated by calanoid copepods and larval stages of some euphausiids.

reproductive biology

Similar to other Eubalaena species.

conservation status

Commercial whalers killed 21,000–30,000 between 1840 and 1849, amounting to about 80% of the total killed between 1839 and 1909. Eastern population almost extinct, having been dealt a final blow by illegal Soviet whaling during 1960s, when more than 370 were killed in the Bering Sea and Gulf of Alaska. Now threatened by effects of small population size. Western population may still be viable, numbering in hundreds. Entanglement in fishing gear a continuing threat.

significance to humans

As true of all balaenids, hunted to very low levels by end of nineteenth century for oil and baleen. Now only significant as a focus of conservation and recovery efforts.

Southern right whale

Eubalaena australis

taxonomy

Eubalaena australis Desmoulins, 1822, Algoa Bay, South Africa.

other common names

French: Baleine du Cap; German: Südkaper; Spanish: Ballena franca del sur.

physical characteristics

Length 43–53 ft (13–16 m); weight 200,000 lb (90,000 kg). One of the stockiest of all whales. Flippers are broad and tend to be more fan-shaped than for most other cetaceans. No dorsal fin or ridge on the broad back. Flukes are very wide and smoothly tapered, with a smooth trailing edge and a deep notch. Largely black, but may have white patches on the belly or back. Some blue-black, light brown, and nearly white individuals have been noted. Callosities on the head are present, as for all right whales. Whale lice are common in creases and folds of the body. 200 to 270 baleen plates up to nearly 10 ft (3 m) long.

distribution

Circumpolar in temperate to subpolar Southern Hemisphere; South Africa, Namibia, southern Mozambique, Madagascar (formerly at least), southern Angola, western and southern Australia, New Zealand (formerly at least), Chile, Argentina, southern Brazil, around numerous oceanic islands such as Crozet, Kerguelen, Amsterdam, and St. Paul (France), Prince Edward (South Africa), Auckland and Campbell (New Zealand), Falkland, South Georgia, Tristan, and Gough (United Kingdom).

habitat

Very widely distributed from near-shore waters to pelagic zone, and from temperate waters south to Antarctic. Main determinant of offshore habitat appears to be availability of dense concentrations of zooplankton. Near-shore wintering grounds typically have a gently sloping sandy bottom, relatively sheltered. Avoidance of unwanted attention by male suitors may help explain female's choice of nursery.

behavior

Migratory, moving south and offshore in summer, north and inshore in winter, with at least portions of population congregating in coastal calving areas. Generally occur in small groups with no obvious social structure apart from close affiliation between mothers and calves. Aggregations form in productive feeding areas and when numerous males attempt to mate with focal female. Breaching (leaping clear of surface) and lobtailing (slapping water with flukes) are common on wintering grounds. Behavior called "tail-sailing" observed off Patagonia, with flukes high above surface acting as a sail to propel whale horizontally. Playful and curious behavior toward buoys, tide gauges, and kelp fronds.

feeding ecology and diet

Zooplankton, mainly copepods and euphausiids, must be found in dense concentrations to allow right whales to feed efficiently. Whales surface skim-feeding on krill (Euphausia superba), which are relatively fast-swimming and adept at predator avoidance, can engage in high-speed bursts (8 knots) and create considerable turbulence.

reproductive biology

Average age at first calving about nine years, some individuals giving birth at six, others not until 13 years old. Single calves are born at intervals of three years. Calving occurs over a period of about four months during austral winter. Calves closely associate with mothers for at least several months but are weaned by one year of age. Gestation assumed to last about 12 months.

conservation status

Lower Risk/Conservation Dependent. Although severely depleted by commercial whaling throughout range, strong recoveries underway in some areas, notably southern Africa, Argentina, and Australia. Numbers there total approximately 7,000, with annual increase rates of 7–8%. In other areas such as New Zealand, Chile, and Madagascar, there is little or no evidence of recovery. An important factor limiting recovery was unreported and only recently disclosed: illegal killing of more than 3,200 southern right whales by Soviet factory ships between 1951 and 1970, a period during which the species was legally protected.

significance to humans

Like other right whales, hunted relentlessly for oil and baleen. For last 30 years, interest in whale-watching has grown rapidly in South Africa, Argentina, and Australia. Marine-protected areas exist in all three countries to protect winter concentrations of right whales and facilitate exploitation as objects of tourism and study.

Resources

Books

Best, P. B., J. L. Bannister, R. L. Brownell Jr., and G. P. Donovan, eds. "Right Whales: Worldwide Status." Journal of Cetacean Research and Management, Special Issue 2. Cambridge, UK: International Whaling Commission, 2001.

Burns, J. J., J. J. Montague, and C. J. Cowles, eds. The Bowhead Whale. Lawrence, KS: Special Publication No. 2. Society for Marine Mammalogy, 1993.

Brownell, R. L. Jr., P. B. Best, and J. H. Prescott, eds. "Right Whales: Past and Present Status." Report of the International Whaling Commission, Special Issue 10. Cambridge, UK: International Whaling Commission, 1986.

Kenney, R. D. "North Atlantic, North Pacific, and Southern Right Whales Eubalaena glacialis, E. japonica, and E. australis." In Encyclopedia of Marine Mammals, edited by W.F. Perrin, B. Würsig, and J. G. M. Thewissen. San Diego: Academic Press, 2002.

McLeod, S. A., F. C. Whitmore Jr., and L. G. Barnes. "Evolutionary Relationships and Classification." In The Bowhead Whale, edited by J. J. Burns, J. J. Montague, and C.J. Cowles. Lawrence, KS: Special Publication No. 2, Society for Marine Mammalogy, 1993.

Reeves, R. R., and R. L. Brownell Jr. "Baleen Whales Eubalaena glacialis and Allies." In Wild Mammals of North America: Biology, Management, and Economics, edited by J. A. Chapman, and G. A. Feldhamers. Baltimore: Johns Hopkins University Press, 1982.

Reeves, R. R., and R. D. Kenney. "Baleen Whales: The Right Whales, Eubalaena spp., and Allies." In Wild Mammals of North America: Biology, Management, and Conservation, 2nd ed., edited by G. A. Feldhamer, B. C. Thompson, and J. A. Chapman. Baltimore: Johns Hopkins University Press, in press.

Rugh, D. J., and K. E. W. Shelden. "Bowhead Whale Balaena mysticetus." In Encyclopedia of Marine Mammals, edited by W.F. Perrin, B. Würsig, and J. G. M. Thewissen. San Diego: Academic Press, 2002.

Randall Reeves, PhD