Archive image from page 528 of The descent of man . The descent of man : and selection in relation to sex descentofmanseledarw Year: 1874 MAMMALS—MEANS OF DEFENSE. 516 are so manifestly useless as teeth, that the animal was formerly- supposed to rest his head by hooking them on to a branch! Their convex surfaces, however, if the head were held a little laterally, would serve as an excellent guard; and hence, perhaps, it is that in old animals they 'are generally broken off, as if by 'fighting.'' Here, then, we have the curious case of the upper tusks of the Babirusa regularly assuming during
Archive image from page 528 of The descent of man . The descent of man : and selection in relation to sex descentofmanseledarw Year: 1874 MAMMALS—MEANS OF DEFENSE. 516 are so manifestly useless as teeth, that the animal was formerly- supposed to rest his head by hooking them on to a branch! Their convex surfaces, however, if the head were held a little laterally, would serve as an excellent guard; and hence, perhaps, it is that in old animals they 'are generally broken off, as if by 'fighting.'' Here, then, we have the curious case of the upper tusks of the Babirusa regularly assuming during the prime of life, a structure which apparently renders them fitted only for defense; whilst in the European boar the lower tusks assume in a less degree and only during old age, nearly the same form, and then serve in like manner solelj'- for defense. Pig. 67. Head of female Ethiopian wart-hog, from 'Proc. Zool. Soc' 1869, showing the same characters as the male, though on a re- duced scale. N. B. When the engraving- was first made, I was under the impression that it represented the male. In the wart-hog (Phacochoerus sethiopicus, fig. 67) the tusks in the upper jaw of the male curve upwards during the prime of life and from being pointed serve as formidable weapons. The tusks in the lower jaw are sharper than those in the upper, but from their shortness it seems hardly possible that they can be used as weapons of attack. They must, however, greatly strength- en those in the upper jaw, from being ground so as to fit closely against their bases. Neither the upper nor the lower tusks ap- pear to have been specially modified to act as guards, though no doubt they are to a certain extent used for this purpose. See Mr. Wallace's interesting account of this animal, 'The Malay Archipelago,' 1869, vol. i. p. 435.
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