Bowhead Whale

Bowhead Whale battle analysis

The bowhead is built like an icebreaker. A third of its 16-metre body is head, arched into the bow shape that names it, and it uses that skull to punch up through sea ice to breathe. Wrapped around the body is a layer of blubber around 45 cm thick, the thickest of any whale, which keeps it warm in near-freezing water and puts a huge depth of fat between any attacker and its vital organs.

Bowheads are slow, cruising at walking pace and managing only about 10 km/h when fleeing, so they cannot outrun killer whales. Instead they belong to the "fight" group of baleen whales and, above all, they use the ice. A bowhead can slip beneath a floe where orcas are reluctant to follow and break through to breathe. Only a small share of Western Arctic bowheads carry killer whale scars, fewer than in other whales studied, though that share is rising as the open-water season lengthens.

Their long life is remarkable. Eye-lens aging put several males past 100 years, traditional harpoon heads have been recovered from recently harvested whales, and bowhead cells repair DNA damage unusually well. Males sing an ever-changing library of songs, with 184 types recorded in one population over three years. In battle terms the bowhead is a near-ceiling defender with very low agility and an attack limited by slowness and the lack of any real weapon beyond its colossal mass and skull.

Habitat & range

Bowheads live almost exclusively in Arctic and subarctic waters with seasonal sea ice, mainly between 60° and 75° north (NOAA). They follow the ice edge as it advances and retreats (ADW), and are the only baleen whale that spends its whole life in these waters.

Diet & hunting

Bowheads filter small crustaceans such as copepods and krill, plus other invertebrates and small fish, straining huge volumes of water through the longest baleen of any whale; each needs about 100 metric tons of prey a year (NOAA). Tagged whales off West Greenland swam slowly at depth with the mouth open, filtering continuously (Simon et al. 2009).

Social life

Bowheads usually travel alone or in small groups of up to six (Wikipedia) and sometimes feed side by side in echelons (ADW). Males sing long, complex and changing songs during the breeding season (Stafford et al. 2018).

Conservation

Globally the bowhead is listed as Least Concern on the IUCN Red List (2018 assessment, as summarized by Wikipedia), though some stocks are listed as endangered. All bowheads are listed as endangered under the US Endangered Species Act (NOAA). Commercial whaling reduced the world population to under 3,000 by 1921; the Western Arctic stock has recovered to about 15,229 (NOAA). Threats now include loss of sea ice, rising killer whale predation, vessel strikes, entanglement, noise and oil and gas development (NOAA).

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