Bowhead whale

• 1. Introduction

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  The bowhead whale, Balaena mysticetus, once turned up with a piece of a nineteenth-century weapon buried in its body. In May 2007, a 15 m specimen was caught off the Alaskan coast. Lodged in it was the 3.5 in head of an explosive bomb lance, a model manufactured between 1879 and 1885. The whale was probably struck sometime in those years. Scientists estimated that it was between 115 and 130 years old when it died.

  This animal is sometimes called the Greenland right whale, the Arctic whale or the polar whale. It is the only baleen whale that lives entirely in Arctic and subarctic waters. What is a skull this massive for? Why do some individuals seem to outlive nearly every other mammal? How did a species hunted by whaling fleets for centuries make it into the present day, and how is it doing now?

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• 2. Head Built for Ice

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  Nearly 40% of a bowhead's total length is head, the largest head relative to body size of any cetacean. The mouth alone takes up almost a third of the animal's length. Inside hang 230 to 360 baleen plates, longer than those of any other whale by more than a metre. They are estimated to reach 4.3 to 5.2 m. One whale that died in 1849 was reported to have baleen of 5.8 m, though that claim has been disputed ever since.

  An adult usually measures 14 to 18 m and weighs 75 to 100 t at most. Females run larger, typically 16 to 18 m, while males average 14 to 16 m. A female killed in the waters off Pond Inlet in the 1800s allegedly measured 19.8 m. The longest whale measured from photographs was 17.57 m.

  The species takes its name from the massive triangular skull, which it uses as an icebreaker. Surfacing from below, a bowhead can easily break through ice around 20 cm thick, according to scientific documentation. Eskimo hunters say it may manage ice as thick as 60 cm. Beluga whales often swim alongside, partly out of curiosity and partly to use the breathing holes the bowheads open.

  In 2013, researchers worked out what a large ridge of blood-rich tissue on the roof of the mouth is for. This organ, the corpus cavernosum maxillaris, is thought to work as a cooling system. A layer of fat at least 40 cm thick protects the whale from cold water, which means exertion can threaten it with overheating. The organ fills with blood, and cold seawater washes over it when the whale opens its mouth.

  The skin is mostly black, with white patches around the flukes, tail, eyes and chin. The chin patch is already visible in newborn calves and grows at the same rate as the animal. Bowheads also rub themselves on rocks to scrape off dead skin cells. Somewhere in the Arctic, one specimen was found that is believed to be a hybrid between a bowhead and a right whale.

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• 3. Slow Giants

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  Two to five kilometres per hour is the normal cruising speed of a bowhead. When fleeing danger, it can reach 10 km/h. The whale is not social, and usually travels alone or in small groups of up to six. A dive can last up to an hour, though most last 9 to 18 minutes. Despite its bulk, it is not considered a deep diver, reaching about 500 ft.

  Feeding means swimming forward with the mouth wide open. Hundreds of overlapping keratin plates hang from each side of the upper jaw. A large upturned lip on the lower jaw braces them, so the pressure of passing water does not buckle or break them. Seawater streams through the fine hairs of the baleen, and the prey is trapped near the tongue and swallowed.

  The menu is mostly zooplankton, including krill, copepods, mysids, amphipods and many other crustaceans. A bowhead eats roughly two tons of food each day. While foraging, it may be alone or in groups of two to 10 or more.

  These whales are highly vocal, using low-frequency sounds below 1000 Hz while travelling, feeding and socialising. Calls for communication and navigation are especially intense during migration. In the breeding season, males produce long, complex, ever-changing songs. A single population sings many tens of distinct songs in one season. Recordings made near Greenland from 2010 through 2014 captured 184 distinct songs from a population of around 300 animals.

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• 4. Calves and Centuries

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  A newborn bowhead calf is typically 4 to 4.5 m long and weighs roughly 1000 kg. It arrives with a thick layer of blubber to survive the cold water. Within 30 minutes it can swim on its own. By the end of its first year it has grown to 8.2 m, and nursing lasts about that long.

  Breeding runs from March through August, and conception is believed to occur mainly in March. Mating happens between pairs and in boisterous groups of several males and one or two females. Gestation takes 13 to 14 months, and a female produces a calf once every three to four years. Sexual maturity arrives at an estimated 15 to 25 years of age, and physical maturity at 50 to 60.

  The oldest female captured while carrying a fetus was estimated at 121 years old. Females may be capable of producing calves for 100 years. Three females estimated at 133, 139 and 149 years old hint at reproductive cessation. Males show no evidence of reproductive aging, and one estimated to be 159 years old was reported to have discharged sperm.

  Scientists measured the ages of other bowheads captured between 1978 and 1996. One male was estimated to be 211 years old, and others fell between 135 and 172 years. Researchers at CSIRO, Australia's national science agency, used genetic analysis to estimate a maximum natural lifespan of 268 years.

  The animal's size makes this puzzling. The bowhead has thousands of times more cells than other mammals, and more cells were once thought to mean more chances for mutations leading to cancer and age-related disease. Yet the bowhead resists both. In 2015, scientists from the US and UK mapped its genome. Comparisons with other mammals flagged two genes, ERCC1 and PCNA, that are both involved in repairing damaged DNA.

  The genome may also reveal why the whale's metabolic rate is low compared with other mammals. Changes in UCP1, a gene involved in regulating body temperature, could explain differences in how its cells burn energy.

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• 5. Naming the Whale

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  Carl Linnaeus described the species in the tenth edition of his Systema Naturae, published in 1758. Bowheads looked identical to relatives in the North Atlantic, North Pacific and Southern Oceans. All were treated as one species, collectively called the right whale, and all carried the name Balaena mysticetus.

  John Edward Gray proposed in 1821 that the bowhead deserved a genus of its own. For the next 180 years, scientists argued about the family Balaenidae. Authorities counted the three right whale populations plus the bowhead as one, two, three or four species, sometimes in one genus and sometimes in two. As recently as 1998, Dale Rice's comprehensive classification listed just two species. B. glacialis covered the right whales and B. mysticetus the bowheads.

  Studies in the 2000s settled it. The three living right whale species form a lineage distinct from the bowhead, so the right whales belong to the separate genus Eubalaena. The bowhead is now the only living member of its genus.

  The fossil record shows no related cetacean after Morenocetus, found in a South American deposit dating back 23 million years. In the 18th century, Emanuel Swedenborg proposed an unknown species of right whale, the so-called Swedenborg whale. Bones claimed to belong to it were later analyzed for DNA, and they turned out to come from bowhead whales.

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• 6. Five Stocks

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  Worldwide, there are an estimated 10,000 to 25,000 bowheads, against an upper estimate of 43,000. Five stocks are generally recognized. They are the Western Arctic stock in the Bering, Chukchi and Beaufort Seas, the Hudson Bay and Foxe Basin stock, the Baffin Bay and Davis Strait stock, the Sea of Okhotsk stock, and the Svalbard-Barents Sea stock. Genetics and tagging suggest the middle two may really be one.

  The Western Arctic whales winter in the southwestern Bering Sea. In spring they follow openings in the ice north into the Chukchi and Beaufort seas. A 2019 study estimated 12,505 animals, below the 2011 figure of 16,820. Surveyors thought there was no significant decline, given the unusual migration and observation conditions in 2019. From 1978 to 2011, the population grew by 3.7% a year, and it may be near its level before commercial whaling.

  In March 2008, Canada's Department of Fisheries and Oceans said earlier estimates in the eastern Arctic had undercounted. Its new figure for Baffin Bay and Davis Strait was 14,400 animals, within a range of 4,800 to 43,000. About 1,200 were off West Greenland in 2006.

  In Hudson Bay, possibly 500 to 600 whales summered each year in the northwestern part in the 1860s. Foxe Basin holds a well-defined gathering area of 3,700 km2 north of Igloolik Island. Cow-calf pairs and juveniles dominate the summer aggregation there.

  The Sea of Okhotsk population likely does not exceed 400 animals, according to Russian scientists. Little research happened there before 2009, when researchers studying belugas noticed concentrations of bowheads. Researchers once called them the forgotten whales. A strayed infant of 6.4 to 7 m was caught in Osaka Bay on the 23rd of June 1969. The first live sighting in Japanese waters, a 10 m juvenile near the Shiretoko Peninsula, came from the 21st to the 23rd of June 2015.

  The Svalbard-Barents Sea population is historically the largest of all and now the most endangered. In 2015, a refuge along eastern Greenland that whaling ships could not reach was discovered. Between Spitsbergen and Greenland, 80 to 100 individuals were sighted, the most ever seen there. Whales have also begun approaching towns such as Longyearbyen.

  In 2012, a tour operator called Arctic Kingdom found a large group in very shallow bays south of Qikiqtarjuaq. Floating skins and rubbing behaviour on the sea bottom suggested moulting, which had rarely if ever been documented in the species. Isabella Bay in Niginganiq National Wildlife Area is the world's first wildlife sanctuary designed specially for bowheads, yet no moulting has been recorded there.

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• 7. Whaling Fleets

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  People may have been eating bowhead whales at Paleo-Eskimo sites from perhaps 4000 BC. Inuit near the Pacific developed specific hunting tools, and the whales provided both food and fuel. The species was prized for blubber, meat, oil, bones and baleen. Like the right whale, it swims slowly and floats after death, which made it ideal prey. Before commercial whaling, an estimated 50,000 existed.

  Basque whalers began the commercial hunt in the 16th century, killing bowheads as they migrated south through the Strait of Belle Isle each fall and early winter. In 1611, the first whaling expedition sailed to Spitsbergen. The whaling settlement Smeerenburg was founded there in 1619. By the middle of that century the populations there were practically wiped out. Whalers had to sail into the West Ice, the pack ice off Greenland's east coast. They reached the Davis Strait by 1719 and Baffin Bay by the first quarter of the 19th century.

  The North Pacific opened up in the 1840s. The Danish whaleship Neptun, under Captain Thomas Sodring, took the first bowheads off eastern Kamchatka in 1845. In 1847, the first were caught in the Sea of Okhotsk. The following year Captain Thomas Welcome Roys, in the bark Superior of Sag Harbor, caught the first in the Bering Strait region.

  The numbers climbed fast. By 1849-50 ships were hunting in each area, and 500 whales died in the Bering Strait that year. More than 2000 died there in 1850. By 1852, 220 ships were cruising the region, and they killed over 2,600 whales. From 1854 to 1857, the fleet shifted to the Sea of Okhotsk, where 100 to 160 ships cruised each year. In 1858 it moved back to the Bering Strait, where most of the fleet spent summers until the early 20th century.

  An estimated 18,600 bowheads were killed in the Bering Strait region between 1848 and 1914. Sixty percent of those died in the first two decades. In the Sea of Okhotsk, an estimated 18,000 were killed during 1847-1867, and 80% of them in the first decade. The ships spread to the western Beaufort Sea in 1854 and to the Mackenzie River delta in 1889.

  Genetic evidence still records the damage. DNA from living whales, and from baleen used in vessels, toys and housing material, shows the Arctic bowheads lost much of their genetic diversity over the past 500 years. Whaling and the cooling of the Little Ice Age, from the 16th century to the 19th, probably shrank the summer habitats that once let Atlantic and Pacific populations exchange genes across ice-covered straits.

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• 8. Protection and Predators

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  A quota of 67 strikes per year has applied to the Bering-Chukchi-Beaufort bowhead since 1998. The International Whaling Commission first introduced a strike quota for this stock in 1978. The current figure represents about 0.5 percent of the population. Commercial whaling, the principal cause of the decline, is over, and bowheads are now hunted at subsistence level by native peoples of North America.

  Alaskan Natives take small numbers. The Alaska Eskimo Whaling Commission co-manages the harvest with the National Oceanic and Atmospheric Administration. Participating villages include Barrow, Point Hope, Point Lay, Wainwright, Nuiqsut, Kaktovik, Gambell, Savoonga, Kivalina, Wales and Little Diomede. The annual harvest has ranged from 14 to 72 whales. In West Greenland and Canada, where the population is estimated at 6,000 and rising, hunting is minimal, below 0.001 percent. In 2024, Inuit hunters of Aklavik in the Northwest Territories were permitted to take one whale. Its meat was shared with Inuvialuit and Gwich'in communities.

  Orca are known predators, though there is no consensus on how many bowheads they kill. Threatened bowheads head for ice and shallow water. Some have killed attacking orcas by striking their heads with the tip of the tail fins. Inuit have a traditional word for this behaviour, which shows the behaviour is not new. Sharks have never been reported attacking bowheads.

  Warming seas now bring orca north more often, a once-rare event. In Hudson Bay, unusual numbers of orca can drive bowheads away from their normal ranges. Less ice coverage means fewer places to shelter, so deaths from orca attacks may rise.

  The IUCN assessment varies by stock. The Svalbard population is critically endangered. The Sea of Okhotsk subpopulation and the Baffin Bay-Davis Strait stock are endangered. The Hudson Bay-Foxe Basin stock is vulnerable, estimated by Canada's Department of Fisheries and Oceans at 1,026 individuals in 2005. The Bering-Chukchi-Beaufort stock is lower risk, conservation dependent. The global population is rated least concern. The bowhead is also listed in Appendix I of CITES and of the Convention on the Conservation of Migratory Species of Wild Animals, which asks its parties to strictly protect the animals.

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