The Hearing- of Whale?.

Otago Witness, Issue 2661, 15 March 1905, Page 72

The Hearing- of Whale?.

The question as to what extent th© scn-c of hearing is developed in whales and dolphins is discussed in Naturwissenchaftliche Wochenschrift for December 18. The means of proving whether animals hear or not are three in number— firstly, whether they respond to the action of sound-waves; secondly, whether they possess a voice; and, thirdly, the structure and relative devclcpment of their auditory apparatus. In the case of cetaceans, their capacity for receiving (and acting upon) soundwaves is demonstrated by the practice of shouting on the part of fishermen when engaged in driving a shoal of porpoises or blackfish into shallow water, for the purpose of frightening their intended victims. As regard's the possession of a voice by eetaoeans, it is stated that one species, the "buckelv/dl" of the Germans, utters during the breeding season a prolonged scream, comparable to the scream of a steam siren, and embracing the whole musical scale, from base to treble. As regards anatomical considerations, it is true that th© external ear is much reduced, the "pinna" being- absent, and the tube, or "meatus,"' of very small calibre. On the other hand, the internal auditory oigans are developed on the plan of those of ordinary mammals, but display certain peculiar nndifications (notably the remarkable shell-like form of the tympanic bone) for intensifying the sound-waves as they are received from the water. It seems, therefore, perfectly evident that whales must hear when in tb/j water. This inference i& confirmed by the comparatively small de■velopment of the other sense organs. The oye, for instance, is very small, and can bo of little vse even at the comparatively small depths Lo which whales are now believed to descend. Again, the sense of smell, judging from the rudimentary condition of the olfactory organs, must be in abeyance ; and whales have do sense organs comparable to the lateral line system of fishes. Consequently, it would seem that when below the surface of the water they must depend chiefly upon the sense of hearing. Probably this sense is so highly developed as to enable the animals, in the midist of the vibrations made by the screwlike movements of the tail, or flukes, to distinguish the sound (or .the vibration*) made by the impact of water against rocks, even in a dead calm, and, in the ca=e of piscivorous species, to recognise by th© pulse in th© water the presence of a shoal of fish. Failing th's <-ypl a nation, it is difficult to imagine how v, hales can find their way about in the semi-darkness, and avoid collisions with looks and rock-bound coast.