Observations on underwater locomotion and flipper movement of the humpback whale Megaptera novaeangliae
Humpback whales (Megaptera novaeangliae) were observed and photographed during winter, 1974 near the West Indies and summer, 1976 near Newfoundland. Prior investigations on whale locomotion based on anatomical inference or surface observations did not describe any specific underwater use of the humpbacks' uniquely long flippers. Our results show that humpbacks achieve a high degree of maneuverability underwater through the active coordinated use of their flippers. Three-dimensional active movements including protraction-retraction, abduction-adduction, and lateral-medial rotations, were observed. The whales could move themselves in all directions independent from fluke-generated forward motion by thrusting with their resilient flippers. At higher swimming speeds (>4 knots) the flippers were used to effect sharply executed ascending or descending banked turns. Analysis of filmed sequences from three adult-calf encounters indicated a reduction of the amplitude and frequency of tailbeats by the adults; calves made tailbeats 4 to 7 times more frequently than adults when maintaining the same speed. The tail and flukes are forcefully moved other than vertically during maneuvering. The significance of these findings is discussed in relation to our knowledge of larger whales.
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