Why do bowhead whales have such large heads?

BBC Wildlife expert Stuart Blackman answers your wild question.

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An adult bowhead’s head accounts for approximately two fifths of its body length. These Arctic giants specialise in particularly small crustacean prey, so they need a large amount of baleen to filter sufficient quantities from the water.

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About 640 baleen plates hang from its upper jaw and, at 4m in length, they are the longest of any whale’s – hence the need for a super-sized head.

Calves don’t develop these front-heavy proportions until they have been weaned. Their bodies virtually stop growing for a few years as they channel resources into their front ends. The youngsters even dismantle bone tissue laid down in their ribs while they were suckling and redistribute it to the skull and baleen areas to accelerate growth.

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  • The head of this whale comprises one-third of its body length of up to 25m; its mouth is the size of a garage.
  • It uses its blowholes as an icebreaker, leaning its bulk against the ice and blowing to clear an airway to the surface.
  • The bowhead may live for 150 years or more – making it one of the longest-lived mammals in the world.
  • Unlike other whales, it lives year-round in Arctic waters off Greenland, Canada and Alaska.