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Bowhead Whale

The Bowhead Whale (Balaena mysticetus), also known as Greenland Right Whale or Arctic Whale, is a marine mammal of the order Cetacea. It can grow to 20 m. (66 ft.), long.

Description

Bowhead whales large dark colored animals with no dorsal fin and a strongly bowed lower jaw and narrow upper jaw. The baleen plates, which are larger than three meters and the longest of the baleen whales, are used to strain tiny prey from the water. The whales have massive bony skulls which they use to break from beneath the ice to breathe. Some Artic hunters have reported whales surfacing through 60 cm (2ft.) of ice in this method. The blubber layer of whale flesh is thicker than in any other animal, averaging 43″“50 cm (17″“20 in).

Taxonomy

The Bowhead Whale is clearly an individual species just like the Right Whale. It has always been recognized as such, and stands alone in its own genus as it has done since the work of John Edward Gray(British zoologist) in 1821. There is, however, little genetic evidence to support this two-genera view. Indeed, scientists see greater differences between the Bowhead Whale and the right whales. Thus, it is likely that all four species will be placed in one genus in some future review.

Distribution

Bowhead Whales are the only baleen whales that spend their entire lives in and around Arctic waters. The Bowhead Whales found off Alaska spend the winter months in the southwestern Bering Sea. They migrate northward in the spring, following openings in the pack ice, into the Chukchi and Beaufort seas, hunting krill and zooplankton. Bowheads are slow swimmers and usually travel alone or in small herds of up to six animals. Although they may stay below the water surface for as long as forty minutes in a single dive, they are not thought to be deep divers.

Reproduction and lifespan

Bowhead Whales are highly vocal and use underwater sounds to communicate while traveling, feeding, and socializing. Some Bowheads make long repetitive songs that may be mating displays. The whales behavior can also include breaching, tail slapping, and spy-hopping. Sexual activity occurs between pairs and in boisterous groups of several males and one or two females.

Breeding has been observed from March through August; conception is believed to occur primarily in March. Reproduction can begin when a whale is 10 to 15 years old. Females produce a calf once every 3 to 4 years, after a 13- to 14-month pregnancy. The newborn calf is about 4.5 m long and approximately 1000 kg, growing to 9 m by its first birthday. The lifespan of a bowhead was once thought to be 60 to 70 years, similar to other whales.

Population status

Bowhead Whales have been hunted for their blubber, meat, oil, bones and baleen. Century old harpoons have been found embedded in some whales’ blubber, showing how old they can get and how they were hunted. They are closely related to the right whale and share with it the hunting-friendly characteristics of slow swimming and floating after death. Before commercial whaling, there were over 50,000 Bowhead Whales in the north polar region (estimated).

Commercial whaling, the principal cause of the population decline, has been discontinued. The stock off Alaska has increased since commercial whaling ceased. Alaska Natives continue to take small numbers of bowhead whales in subsistence hunts each year. The status of the other bowhead stocks is less well known. These stocks are thought to be very small, probably in the low hundreds, for a possible worldwide population of 8,000″“9,200 individuals.

Bowhead Whale


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