Balaena Mysticetus: The Arctic’s Longest-Living Mammal

The Bowhead whale, Balaena mysticetus, is a baleen whale that lives its entire life in Arctic and sub-Arctic waters. It possesses specialized biological traits that allow it to thrive in its icy habitat, setting it apart from other whale species.

Unique Physical Anatomy

The Bowhead whale’s enormous, triangular skull can constitute up to one-third of its total body length. This reinforced, bow-shaped skull is powerful, enabling the whale to break through thick sea ice for breathing holes. The skull also supports the largest mouth of any animal on Earth.

The Bowhead possesses the longest baleen plates of any whale, with individual plates reaching up to 13 feet (4 meters). These plates, numbering between 230 and 360 on each side of the mouth, filter food from the water. Its blubber layer can be up to 11 inches (28 cm) thick, providing insulation against frigid temperatures. The Bowhead also lacks a dorsal fin, a trait that facilitates movement under ice sheets.

Arctic Life and Diet

The Bowhead whale maintains a nearly circumpolar distribution in Arctic and sub-Arctic seas. Its movements are dictated by the seasonal advance and retreat of the ice edge. During winter, Bowheads reside near pack ice or in open water areas called polynyas. As the ice recedes, they migrate into channels to access feeding grounds.

As a filter-feeder, the whale swims slowly with its mouth open, straining water through its baleen plates. Its primary food sources are small crustaceans, particularly copepods and krill.

The Longest-Living Mammal

The Bowhead whale is recognized as the longest-living mammal known to science, with evidence suggesting they can live for more than 200 years. Age can be determined by analyzing the aspartic acid racemization in the lenses of their eyes.

The discovery of old stone harpoon tips embedded in the blubber of modern whales provides more evidence. Some of these artifacts date to the 19th century, indicating the whale survived previous encounters with whalers. This extended lifespan corresponds with a slow rate of maturation. Females give birth to a single calf every three to four years, reaching sexual maturity around age 25.

Conservation and Cultural Significance

Commercial whaling during the 19th and early 20th centuries severely depleted Bowhead whale populations, and several distinct populations were driven to the brink of extinction. Following international protections, such as the 1966 moratorium on whaling, some populations have begun to recover.

The conservation status of Bowhead whales varies by region. The largest population, in the Bering-Chukchi-Beaufort seas, has shown substantial recovery and is now considered of “Least Concern” by the IUCN. However, other stocks, such as the one in the Okhotsk Sea, remain at very low numbers. Bowhead whales also hold deep cultural and subsistence importance for Indigenous communities throughout the Arctic, who have hunted the whale sustainably for millennia.