Bowhead whales, like humpback whales, have elaborate and complex songs. Researchers are finding that pods of bowhead whales share songs, and sing a variety of shared songs during migration. Underwater recordings made in the spring of 2011 documented a dozen different songs sung by at least 32 whales swimming off Point Barrow. The recordings also pick up the eerie, ringing vocalizations of bearded seals - the bowhead songs are deeper, in a lower register.
Biologists suspect the songs are sung by males, related to breeding. The songs are recorded by sonobuoys, underwater recording devices that are sunk and rest on the sea floor for about six months. Researchers send the sonobuoys a signal that causes them to surface so they can be recovered. The devices are deployed in a line from the Bering Sea almost 1,500 miles east to the Canadian Beaufort Sea, recording songs as the whales move through their migratory route in the Arctic.
The North Slope Borough, Cornell's Bioacoustics Research Program, and other collaborators have been recording bowhead vocalizations, beluga whales, bearded seals and other animals in the Beaufort Sea for years. The recordings help determine the size of the bowhead population, which is growing at a rate of almost four percent a year. In 2011 the population was estimated at about 17,000 whales, good news for a population that heavily impacted by commercial whaling.