With his usual candour Darwin noticed the evidence which seemed to tell against his view. Mr. Belt, he says, “believes that within the tropics it is an advantage to man to be destitute of hair, as he is thus enabled to free himself of the multitude of ticks (acari) and other parasites with which he is often infested, and which sometimes cause ulceration.” Darwin doubts, however, whether this evil is of sufficient magnitude to have led to the denudation of the body through Natural Selection, “since none of the many quadrupeds inhabiting the tropics have, as far as I know, acquired any specialised means of relief.” But as primitive man’s habits of cleanliness are much inferior to those of animals, this objection loses its force; and it is, moreover, weakened by the testimony of Sir W. Denison that “it is said to be a practice with the Australians, when the vermin get troublesome, to singe themselves.” We also know that the ancient Egyptians[Egyptians] shaved off their hair from motives of cleanliness.
However, it is not likely that the superior advantages of cleanliness and freedom from parasites would alone have sufficed to produce so great a change in man as the loss of his hair. It is more probable that the sun was the chief agent in accomplishing this transformation. I fail to see the force of Darwin’s contention that the fact that “the other members of the order of Primates, to which man belongs, although inhabiting various hot regions, are well clothed with hair, generally thickest on the upper surface, is opposed to the supposition that man became naked through the action of the sun.” For these animals commonly live in forests and on trees, where they are protected from the rays of the sun, which is not the case with man.
Furthermore, Darwin himself mentions some circumstances which point to the conclusion that the sun is the cause of man’s nudity. He says, for instance, that “elephants and rhinoceroses are almost hairless; and as certain extinct species which formerly lived under an arctic climate were covered with long wool or hair, it would almost appear as if the existing species of both genera had lost their hairy covering from exposure to heat. This appears the more probable as the elephants in India which live on elevated and cool districts are more hairy than those on the lowlands.”
Bearing in mind what was said in the chapter on the Complexion regarding the negro’s skin, there is no difficulty in understanding why Natural Selection should eliminate the hairy covering of the skin while favouring a dark complexion. Hair not only absorbs the sun’s heat, but retains that of the body; hence a hairy man not living on trees would be very uncomfortable in Africa, and likely to succumb to the enervating effects of high temperature. The negro’s naked skin, on the other hand, is, as we have seen, specially devised as a body-cooler. The black pigment protects the underlying nerves of temperature, while the solar heat absorbed by this pigment is immediately radiated in the form of perspiration. Now we can see not only why the negro’s skin is more velvety, smooth, and hairless than our own, but why its sweat-pores are larger and more numerous than in our skin.
At a later stage of evolution Sexual Selection probably came in to aid in this process of denudation. We may infer this, in the first place, from the analogous case of apes who have denuded and variously-coloured patches on the head and elsewhere, which they use for purposes of display, to attract the notice of the opposite sex; in the second place, from the fact that there are not a few tribes who pluck out their hairs. “The Fuegians threatened a young missionary, who was left for a time with them, to strip him naked, and pluck the hairs from his face and body, yet he was far from being a hairy man;” and “throughout the world the races which are almost completely destitute of a beard, dislike hairs on the face and body, and take pains to eradicate them.” Darwin also notes some facts which, by analogy, seem to make it probable that “the long-continued habit of eradicating the hair may have produced an inherited effect.”
In the case of the white race we cannot rely so much on the action of the sun as accounting for the absence of hair, but must place more especial emphasis on Sexual Selection. We are warranted in doing this by the consideration that Taste for Beauty is more developed in the white race, and therefore has more influence in controlling the choice of a mate. “As the body in woman is less hairy than in man, and as this character is common to all races, we may conclude” with Darwin “that it was our female semi-human ancestors who were first divested of hair,” this character being then transmitted by the mothers to their children of both sexes.
The two universal traits of Beauty which chiefly guided man in the preference of a hairless skin were evidently Smoothness and Colour. One need only compare for a moment the face of a female chimpanzee, its leathery folded skin and straggling hairs, with the smooth and rosy complexion of a European damsel, to understand that, leaving touch out of consideration, sight alone would have sufficed to give the preference to the hairless skin. But since we derive less direct advantage than the tropical races from such a skin, cases of reversion to the hairy type are more common among us than with them, and our bodies in general are more hairy.
BEARDS AND MOUSTACHES
The elimination of hair from those parts of the body where it is less beautiful than a nude skin, is only one of the functions of Sexual Selection. Another equally important function is the preservation and elongation of the hair in a few places for ornamental purposes.
“We know from Eschricht,” says Darwin, “that with mankind the female as well as the male fœtus is furnished with much hair on the face, especially round the mouth; and this indicates that we are descended from progenitors of whom both sexes were bearded. It appears, therefore, at first sight, probable that man has retained his beard from a very early period, whilst woman lost her beard at the same time that her body became almost completely divested of hair.”