Bowhead whales are extremely rotund overall, but often have a distinct "neck" region. The head is large (up to two-fifths of the body length); the upper jaw is arched and narrow when viewed from above. The mouthline is strongly bowed, and the eye is placed just above the corner of the mouth. There is no dorsal fin or ridge, and the back is very broad. The flippers have blunt tips and the flukes are wide with smooth contours. There is a large muscular bulge in the blowhole area.
Predominantly black in color, bowheads have a white patch at the front of the lower jaw; this patch often has several dark gray to black spots, each indicating the position of a chin hair. There is also often a light gray to white band around the tail stock, just in front of the flukes, and sometimes other white or light gray areas on the body. The white on the tail expands with age, and very large, old bowheads may have an almost completely white tail. Some lighter-colored bowheads are occasionally seen.
Male bowhead whales range to 18 m in length, females to 20 m. Weights of large individuals have been estimated at about 75-100 metric tons. Calves are about 4-4.5 m long at birth.
Bowheads have the longest baleen plates of any whale. The 230-360 plates in each side of the jaw can reach lengths of 5.2 m; they have long, fine fringes. The plates are dark gray to brownish-black, generally with slightly lighter fringes. As is true for the closely-related right whales, the blow is V-shaped and bushy.
Can be Confused With
Gray whales use some of the same summer range as bowheads, but the gray whale’s dorsal hump and knuckles, and differences in head and body shape and coloration between the two species should make them distinguishable. Right whales might also overlap with bowheads, but usually the two species are separated by their ecological preferences. The right whale’s callosities and absence of light chin and peduncle patches will allow them to be distinguished from bowheads.
Bowheads are found only in arctic and subarctic regions. There are five stocks recognized in the North Atlantic Ocean, and the Bering, Beaufort, Chukchi, and Okhotsk seas. These animals live much of their lives in and near the pack ice, migrating to the high arctic in summer, but retreating southward in winter with the advancing ice edge.
Ecology and Behavior
Bowhead whales are usually seen in groups of three or fewer, but larger aggregations form during the fall migration and on the feeding grounds. Although often slow-moving, bowheads breach and engage in other aerial behavior. They frequently lift their flukes before a steep dive. Low frequency calls are common, at least during migration.
Calves are born mainly in spring as whales migrate toward feeding grounds. The breeding system is thought to be similar to that of the right whale, with males using a form of sperm competition.
Feeding and Prey
Small to medium-sized crustaceans, especially krill and copepods, form the bulk of the bowhead’s diet. They also feed on mysids and gammarid amphipods, and the diet includes at least 60 species. Bowheads skim feed at the surface and feed in the water column. It has recently been suggested that they also feed near the bottom, but probably do not directly ingest sediments as gray whales routinely do. During surface skim feeding, coordinated group patterns have been observed, including whales feeding in echelon (V-shaped) formation.
Threats and Status
Heavy hunting, beginning in the1500s, has left four of the five recognized bowhead stocks highly endangered. However, the Bering-Chukchi-Beaufort stock is thought to number about 8,000 animals, and limited whaling by Inuit people in Alaskan waters is allowed by the International Whaling Commission and the United States government. This, along with small (but not insignificant) kills by the Russians and Canadians may be factors in the recovery abilities of the affected stocks. The major non-direct threat to these animals is disturbance from oil and gas exploration and extraction activities in the Arctic region.
Currently, bowhead whales are listed as ‘Endangered’ (IUCN – Okhotsk Sea and Baffin Bay/Davis Strait stocks), ‘Vulnerable’ (IUCN – Hudson Bay/Foxe Basin stock), ‘Lower Risk/Conservation Dependent’ (IUCN – all other stocks), and ‘Endangered’ (ESA).
Braham, H.W., W.M. Marwuette, T.W. Bray and S. Leatherwood (eds.). 1980. The bowhead whale: Whaling and biological research. Marine Fisheries Review 42:9-10.
Burns, J.J., J.J. Montague and C.J. Cowles (eds.). 1993. The bowhead whale. Society for Marine Mammalogy, Special Publication No. 2.
Reeves, R.R. and S. Leatherwood. 1985. Bowhead whale Balaena mysticetus Linneaus, 1758. pp. 305-344 in S.H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Volume 3: The sirenians and baleen whales. Academic Press.
Rugh, D.J. and K.E.W. Shelden. 2002. Bowhead whale. pp. 129-131 in W.F. Perrin, B. Würsig and J.G.M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.