The sperm whale is frequently subject to deformity of the lower jaw, two instances of which we have seen, in which the deformity was so great as to render it impossible for the animal to find the jaw useful in catching its prey, or even, one might have supposed, in deglutition; yet these whales possessed as much blubber, and were as rich in oil as any of a similar size we have seen before or since. In both these instances of crooked jaws, the nutrition of the animal appeared to be equally perfect. In both cases the jaws were bent on one side. It would be interesting here to inquire into the causes of this deformity; but whether it is the effect of disease, or the consequence of accident, would be difficult to ascertain. Old whalemen affirm that it is caused by fighting. They state that the sperm whale fights by rushing head first one upon the other, their mouths, at the same time, wide open; their object appearing to be the seizing of their opponent by the lower jaw, for which purpose they frequently turn themselves on their side. In this manner they become, as it were, locked together, their jaws crossing each other, and in this method they strive vehemently for the mastery. We have never had the fortune to witness one of these combats, but if it be the fact that such take place, we need not wonder at seeing so many deformed jaws among sperm whales; for we can easily suppose the enormous force exerted on these occasions, taking into consideration, also, the comparative slenderness of the jaw-bone in this animal. From these facts it may at least be surmised, with a great degree of probability, that the mode of procuring food as above stated is the true one; for with a jaw so much deformed, the animal would seem incapable of pursuing his prey, and would consequently gain but a very precarious subsistence, did not its food actually throng about its mouth and throat, invited by their appearance, and attracted in some degree, as is supposed, by the peculiar and very strong odor of the sperm whale.
The teeth of the sperm whale are merely organs of prehension. They can be of no use for mastication, and consequently the fish, etc., which he occasionally vomits present no marks of having undergone the process.