The Motion of Whales during Swimming

Abstract

IN our two well-known Danish zoological handbooks it is stated regarding the swimming of whales, in one that “It is the screwing actions of the hind part of the body (the tail) which force the whale through the water, the tail fin acting only to balance up and down,” in the other that “The whales move in the manner of fish by flapping the tail from side to side”; according to a verbal statement, this was observed by the author himself on porpoises in a tank in the Zoological Garden. In the foreign literature I have found information1 that whales, when swimming rapidly, move the tail fin up and down; when they swim slowly, on the other hand, they perform screw-like motions. Porpoises have been observed in tanks in England to swim by moving the tail fin up and down with slight undulations to each side.