Which whale species has the thickest blubber?

The bowhead whale has the thickest blubber of any whale species. Living almost exclusively in Arctic and subarctic waters, it depends on an exceptionally substantial fat layer to retain heat in freezing seawater and to store energy when food is scarce.

Bowhead blubber can reach roughly 40 centimeters in thickness, with some reports suggesting measurements approaching 50 centimeters in particular areas or individuals. The layer is not simply passive insulation: it contains vascularized tissue and acts as a major energy reserve. Bowheads also have unusually thick skin and a large body, which further helps them cope with the Arctic environment.

Right whales are a common alternative answer because they also possess remarkably thick blubber and were historically prized by whalers for their oil. However, the bowhead is generally recognized as the record-holder. Its other Arctic adaptations include a massive triangular skull for breaking through sea ice, a huge mouth, and baleen plates that can approach 4 meters in length.