The Arctic whale that headbutts ice and may live 200 years
Bowhead whales may outlive every other mammal, reaching more than 200 years. They spend their lives in Arctic and subarctic seas, smashing breathing holes through ice with a massive triangular skull, and beluga whales sometimes tag along to use the openings. Near Greenland, a group of about 300 sang 184 distinct songs over four years.
The head is extraordinary. It makes up nearly 40% of the body, the largest proportion of any cetacean, and holds the biggest mouth of any animal. Hanging from the upper jaw are 230 to 360 baleen plates, the longest of any whale, at up to about five metres. The whale feeds by swimming slowly forward with its mouth open while water strains through the keratin fringes, and a huge upturned lower lip braces the plates so they do not buckle.
Scientists have documented bowheads breaking through ice about 20 centimetres thick, and Inuit hunters say they can manage 60. Wrapped in 40 centimetres or more of fat, a working whale risks overheating. A 2013 study explained a ridge of blood-rich tissue on its palate that swells during exertion and apparently dumps heat into the water flowing through the mouth. Bowheads also rub against rocks to scrape off dead skin.
Classification took centuries to settle. Linnaeus lumped bowheads with right whales in 1758, and the family was reshuffled repeatedly until studies in the 2000s confirmed that the right whales belong in their own genus. Bones once credited to the mysterious Swedenborg whale proved, through DNA, to be bowhead. Genetic work on baleen from old vessels, toys and houses shows the population lost much of its diversity over the last 500 years, blamed on whaling and the Little Ice Age.
Life proceeds slowly. Adults reach 14 to 18 metres and up to 100 tonnes, cruise at 2 to 5 kilometres an hour and usually dive for 9 to 18 minutes. Females mature at 15 to 25 and calve every three to four years after a 13-to-14-month pregnancy, and a male thought to be 159 was still fertile. Hunting crashed their numbers before a 1966 moratorium.
Source: Bowhead whale
