Bowhead age determination is difficult, but their life span is probably similar to humans. Instead of having grooved expandable throats like most other baleen whales, bowheads have very large mouths to maximize the amount of water taken in and to hold captured food. Bowheads feed by swimming with their mouths open and straining zooplankton out of the water with their baleen. Each bowhead carries about 660 baleen plates which hang down in two racks, one from each side of the upper jaw. The inner margins of the baleen plates are fringed with fine bristles that act as a hairy curtain to sieve food out of the water.
Bowheads feed at all depths, from the surface to the bottom.
Bowheads feed year- round in the Beaufort, Chukchi, and Bering seas. They use a variety of strategies, including feeding under ice and swimming in groups in V-shaped formation, to increase feeding efficiency. Bowheads often depend for survival upon their ability to travel through ice-dominated waters. Researchers using hydrophones have detected bowheads traveling through lead systems that appear to be completely covered by ice. When migrating they make long dives, generally from 6 to 17 minutes, and then usually surface for a series of four to nine blows.