The bowheads spend the summer in the Canadian Beaufort Sea, then migrate west along the continental shelf of the Beaufort Sea to Point Barrow from August through October. Next, the whales cross the Chukchi Sea and travel south along the Russian coast, passing through the Bering Strait by November. The gestation period is 13 to 14 months. Most bowhead whales calve during April, May, or early June. After plunging from the internal body temperature of their mothers into near freezing water, the newborns must begin swimming north with the migrating herd almost immediately.
Bowhead whales are shorter but heavier at birth than most other baleen whales.
Bowheads calve at about three to four year intervals. 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.