The bowhead whale, Balaena mysticetus, is an exclusively northern species that inhabits arctic and subarctic waters, never straying far from the edge of the pack ice. In Canada, the bowhead can be separated into two main stocks: eastern and western Arctic. The eastern population was almost decimated by whalers in the mid-1800s, and it is estimated that only 450 whales in this stock persist today.
The bowhead gets its common name from the curved arching of its upper jaw, and its species name, mysticetus, means "whale with a moustache," referring to the sheets of baleen that hang from its jaw. Baleen consists of horny plates with fibrous fringes and acts like a massive filtration system. The bowhead feeds by swallowing a large mouthful of sea water, which is then squeezed back through the baleen as the tongue is moved forward. Zooplankton are trapped by the baleen, and the tongue simply licks them off. Bowheads generally have about 360 baleen plates hanging from each side of their upper jaw and they are the longest of any whale up to three metres long!
Water is an excellent conductor of heat, meaning that life in cold, arctic waters requires a great deal of insulation. Bowhead whales grow up to 18 m long and weigh 60 to 100 tonnes, and yet they can extract enough resources from a diet of krill to produce a 50 cm thick layer of blubber that weighs 30 tonnes.
Besides humans, the only predators of bowheads are killer whales. In order to elude this enemy, bowhead whales seek refuge in waters with abundant ice. Orca often abandon these pursuits to avoid damaging their prominent dorsal fin.
Bowhead whales bear a distinct white patch on their chin and tail, while the rest of their body is black, blue-black, dark grey, or dark brown. They often dive deeper than 200 metres and can remain submerged for 4 to 20 minutes. They are slow swimmers and generally travel in small groups of 3 or 4 individuals.
Mature females give birth every 24 years to a single calf in the spring. Calves range in length from 3.6 m5.2 m at birth and are nursed for a full year. On a daily basis, calves consume approximately 700 litres of milk, which has a 50% fat content.