DescriptionBowhead whales are easily distinguished by their enormous head, white chin, and lack of dorsal fin. They have the longest baleen of the baleen whales, growing to more than 4 m (13 ft). Bowhead whales are found in five separate populations in the Arctic Ocean, migrating north and south with the seasonal movement of the edge of the pack ice. Bowhead whales produce a wide variety of vocalizations, ranging from moans at a constant frequency to calls made up of a series of pulses varying in intensity, frequency, duration, and interpulse interval. Most of their calls are simple moans within the 25-900 Hz range, but repetitive moan sequences have also been described as songs. Scientists use the bowhead vocalizations and visual sightings of animals to count the whales during their migration. They have found that estimates of the number of bowhead whales based on only sightings data or only acoustic data are too small. Only by combining the two types of data are scientists able to accurately monitor the bowhead whale populations .