Bowhead whale - Ecology & Habitat

Among the longest-lived animals on earth?

The species is essentially found in the arctic region, in association with ice floes. Its movement patterns are therefore influenced by the melting and freezing of the ice. During the summer season it visits bays, straits, and estuaries.

Social Structure
Bowheads have been reported to feed in groups of up to 14 animals in V-shape formation, while groups consisting of two adults and a calf also were seen to persist for at least a few weeks.

Bowheads are usually solitary or in groups of two or three individuals, who may aggregate by age and sex. Larger groups may be formed during migration; young specimens of the Bering Sea population move North first during Spring migration, followed by large males and females with calves.

Life Cycle
Because these whales do not have teeth - often used to estimate age in other mammals - it can be difficult to determine their age. However, data has shown that bowhead whales may be among the longest-lived animals on earth. Based on the recovery of stone harpoon tips in their blubber, and from analysis of eye tissue, scientists believe that the life-span of bowhead whales can be over 100 years. One individual in a study was believed to be more than 200 years old.

Breeding
Bowheads usually reproduce in the late winter, with births occuring between April and June of the year after (13 months gestation). They give birth to a single calf of 400 to 500cm every 3 to 6 years, which weans 6 to 12 months later.

Diet
Bowheads filter their food through baleen, opening their mouths and straining zooplankton from the surface, the water column, or the sea floor. Zooplankton includes copepods and small shrimp-like animals called euphausiids. Scientists estimate that a bowhead whale needs to eat about 100 tonnes of crustaceans each year.

They maintain a thick layer of blubber that insulates them from the icy arctic waters. Bowhead whales often congregate in the autumn in areas with rich food resources. One such area is Isabella Bay near Clyde River, Nunavut, Canada, which WWF is helping to preserve as a whale sanctuary.