LACK OF HAIR ON MAN.

Star (Christchurch), Volume XLIV, Issue 301, 19 December 1931, Page 17 (Supplement)

LACK OF HAIR ON MAN.

Comparsion Made With the Apes.

jyjAN DID NOT LOSE the bulk of hia body hair because he took to wearing clothes, or because of any other environmental change adopted by him or forced upon him. The relative hairlessness of humankind is simply the most extreme expression of a general evolutionary trend to reduce the hairy coat in all the highest primates—man and the large apes. Some of the great apes have even fewer hairs to the square inch of scalp, and the gorilla at least is often not as hairy-chested as a man.

This is among the conclusions reached through a comparative study of hairiness among monkeys, apes and men, conducted by Dr Adolph H. Schultz of the Johns Hopkins Medical School and reported to the journal “ Human Biology.” Dr Schultz selected areas of one square centimetre each, on head, chest and back of human beings of three different races and of many species of monkeys and apes. On each of these areas he painstakingly counted the hairs and then multiplied the number by the total area in square centimentres to get the total number of hairs. Several of his results are not what might be expected from a priori assumptions. Human beings were found, for example, to have more hairs on their heads than some of the apes. The average number of scalp hairs a square centimetre was 312 for man and 307 for thirteen specimens of the large anthropoid apes. The gibbon, a small Asiatic ape, was much hairier on the head, with 2035 hairs a square centimetre, and one monkey species, Aotus, had twice as many as that, with 4083. Gorillas are less hairy-chested than many men. Two adults had only six and three hairs, respectively a square centimetre, whereas a man—not a very hairy-chested one at that—had nine. Two chimpanzees were also relatively bare-chested, with counts of forty-three and fifty-nine, while the gibbon again showed a high count of 499. In regard to the back, man scored an absolute blank, with zero hairs a square centimetre; the anthropoid apes averaged only 276, but the gibbons 1727. Various lower monkeys were even more hairy-backed.