“Although they are for the most part content with vegetable diet, gibbons sometimes eat animal food, such as lizards; and Bennet saw a siamang seize and devour one of these animals whole.... They do not, however, display the keenness of scent and quickness of sight which distinguish some animals of a lower order; such as canine beasts of prey and ruminants manifest in many different ways.” (p. 256).
Now, it will be noticed in the above connection that (1) these apes are, by reason of their peculiar anatomical and physiological construction, incapable of competing with the carnivora for food of that character—and hence naturally disqualified to live upon it; and (2) these animals do not _naturally_ live upon this food by choice, when other and, to them, more natural food is forthcoming. Only in the last stages of hunger do they resort to food of this nature, which they are obviously driven to by extremity, and are disqualified to eat by reason of their peculiar construction. An animal can be driven to eat anything if he is hungry enough. That does not prove that what he eats is his natural food, nevertheless! Instinct, and other considerations, must determine that.
_The Frugivora._—The orang and the gorilla are perhaps the best examples of this class of animals. Some bats and kangaroos may be included in it also. Animals belonging to this class have thirty-two teeth—sixteen in each jaw; four incisors or cutting teeth; two pointed teeth, known as cuspids, four small molars, known as bicuspids, and six molars. The eye-teeth project somewhat beyond the others and fit into a blank space in the lower row, the other teeth articulating uniformly. I have referred to the uses of this large eye-tooth elsewhere (p. 29).
_The Teeth of Man._—Now when we come to consider the teeth of man, we are at once struck by the fact that they correspond, in almost every particular, with the teeth of the gorilla and other frugivorous animals; and the fact they do not at all resemble or correspond to the teeth of any other animal! To the teeth of the herbivora, the carnivora, the omnivora, etc., they bear but the slightest resemblance, while they agree in almost every respect with the teeth of frugivorous animals. If we compare the teeth of man with those of the orang, the gorilla, or other frugivorous animal, we find that the number, the arrangement, the structure, the nature, and the size of the teeth are almost identical; while they bear but the smallest resemblances to the teeth of any other animal or _genera_. The complete absence of intervening spaces between the human teeth characterises man as the highest and purest example of the frugivorous animal. Man possesses no long, canine tooth, capable of catching and holding a captured prey; he possesses no tusks, like the omnivorous animals, and in every other way bears no resemblance whatever to any other animal—while his teeth do bear the very greatest and most detailed resemblance to the teeth of the apes and frugivorous animals generally. Bearing all these facts in mind, then, we surely can have no hesitation in classifying man as a frugivorous animal—so far as his teeth are concerned. Considered from that point of view, man must be classed with the pure frugivora.