The case of our own forefather also differs somewhat from that of other tropical mammalia; because, by hypothesis, he underwent pretty rapidly such an extraordinary change of life; which may have brought him into circumstances where vermin, formerly negligible, became highly injurious. “Monkeys,” as Belt observes, “change their sleeping-places almost daily”; the Orang is said to construct a fresh nest every night; this is also reported of the Gorilla. Not improbably, then, daily change of locality was the practice of the original anthropoid stock, whence we also are descended: thereby avoiding the accumulation of vermin. Did the hunting life introduce a new habit? In the old frugivorous forest life, the custom was to get up into some tree for the night, and within a short radius there were hundreds equally suitable; and, therefore, there was nothing to check the natural preference for a fresh one. When, however, the hunting pack began to make its lair on the ground, there was no such wide choice amongst caves, rock-shelters, or thickets: one might be better than any other for miles around. If, then, they settled down there as in a common lair, the circumstances were, for the time, favourable to the multiplication of vermin, and therefore to nakedness of skin, in order the more easily to be rid of them. Perhaps, then, this difference of Man from the anthropoids may be referred to one common cause with all the others—the hunting life. There, too, the defilement of blood made fur inconvenient to animals not apt to cleanse themselves, like those in the true carnivorous heredity and tradition. When we consider how injurious some insects are to vertebrate life, being suspected of having caused in some cases the extinction of species, can it be said that facility in ridding oneself of such vermin as lice and ticks is an inadequate cause of human nakedness, or not one that might outweigh the drawbacks of cold and wet? It is not, however, incompatible with the action of sexual selection, tending to the same result; nor, again, with the preferential destruction of hairy children if ever infanticide was practised. A further possible ground of deliberate selection may have been the mere ambition of differing from other animals; for a tribe on the Upper Amazons is reported to depilate to distinguish themselves from the monkeys, and the wish to be superior to other animals led a tribe in Queensland to pretend that they, unlike kangaroos, etc., have no fathers according to the flesh.[20] Admitting that this last motive can hardly have been primitive, still, our nakedness may be a resultant of several causes.