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The Bowhead whale (its scientific name being Balaena mysticetus) is a large marine mammal that has adapted to living in and around Arctic sea ice. Scientists believe that bowhead whales are among the longest living mammals on the planet. After 50 years of age, bowhead whales continue to grow in size while their life-span is believed to be over 100 years old.
Image: A portion of a bowhead whale's skull.
Why this species is important
Bowhead whales were and still are an important traditional source of food, as well as building and tool-making materials. In the 1800s, many European and North American countries used bowhead whale oil for lamps and lubrication and whale baleen for carriage whips, corsets, latticework, and screens. Hunted to near extinction, laws were set in place making it illegal to hunt these mammals.
Climate change and the bowhead whale
Bowhead whales spend their entire life in Arctic waters. Only the thickness of the sea ice restricts the northern limit of bowhead whale distribution. Due to their ability to navigate cold waters, they have been able to maintain their territories.
As the air temperature increases in the Arctic due to climate change, the waters of the Arctic are also expected to warm up. Scientists do not know how this will impact the bowhead whale. Many fear that as the water warms, predators such as the killer whale will be able to enter and survive in areas where they could not before. This could have a major impact on bowhead whale populations as they would face new threats and predation they have never faced before.
Air temperature is directly related to water temperature. This illustration depicts the planet's air temperature and how it is expected to change over a 90 year period. Sliding the scale from left (2000) to right (2090), the air temperature increases. As the climate warms the average air temperature will rise by at least 12°C.
2090 (*projected air temperature)
2000 (air temperature)
Global warming factors
An increase in global warming would see bowhead whales moving further north. As the ice in the many channels of the Northwest Passage decreases, eastern and western populations of bowhead whales will likely overlap, causing a major change to their distribution.
Although humans harvest a few bowheads each year, killer whales travelling in pods are natural predators of bowhead whales. The northward movement of killer whales, as the Arctic waters lose their ice cover, may lead to increased predation on bowhead whales.
As bowhead whales live only in the Arctic region, they have adapted to the region's cold climate. Adaptations include a thick blubber that provides the whale with insulation against the cold water; the absence of a dorsal, or back, fin, which allows the whale to surface through the sea ice without suffering injury; and a massive head that can break through the ice for a breathing hole.
Food for thought
Hanging from the roof of a bowhead whale's mouth are huge plates of baleen. The head and upper jaw are bow-shaped to accommodate the baleen, hence its name.
Baleen is made of keratin, the same substance found in human fingernails and hair. The baleen plates are used in feeding to filter out water and trap small organisms known as krill or plankton. Bowhead whales open their large mouths to allow a large amount of water to enter. The whale then pushes the water out through the baleen with its tongue and the mass of small organisms is swallowed.
Bowhead whale feeding
Bowhead whales (like all baleen whales) are omnivores that feed on plankton and tiny crustaceans from the water. Bowhead whales are skimmers or filter feeders that feed by swimming slowly along with their mouth open. When a Bowhead whale is feeding, you can see it skimming the water, then diving down.
This video shows a bowhead whale feeding.
Transcript: Bowhead whale feeding
The flipper of a bowhead whale breaches the water. A pod of bowhead whales can be seen in the distance. The tail of one of the whales breaches the water. Students on Ice on a Zodiac boat, observing the whales. The tail of one of the bowhead whales breaches the water once more.