Our balding isn't peculiar to ourselves. It is found in several primate groups - apparently having evolved independently in all of them. South American uakari monkey balds with age even more completely than human beings. Male uakaris generally become more bald than females. Among the African monkeys the stump-tailed macaque males bald with age. Among the apes both the chimps and orangs experience balding, but the trait is highly variable among chimps - occurring more notably with age and more so among males than females.
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What has this done for the male scalp? It has reversed the selection pressures for status opposite to long tresses - a bald head. One identifies a full head of hair with femininity and youth. The actors who are chosen to play the roles of very young men in movies or on television frequently have an unusually low hairline, so that the forehead is reduced to a narrow band of skin. This is also true of the "baby-doll" actresses. People with this kind of hairline look younger than their age.
The status signal of the high forehead is obscured by our current accent on youth. Head shaving is a common phenomenon among many tribes and often is done only by males. Interestingly enough, it is sometimes performed in a manner which exaggerates the natural balding patterns. For example, the South American Yanomano shave the crown of the head, leaving a wreath of hair. Scars from battle are exhibited in this manner. Another South American tribe, the Tchikrin, pluck all facial hair, even in small children. The men, especially, have their hair plucked back from the forehead to the crown or hair whorl area. It was a common practice during the 1800's for Chinese males to shave the forehead well back to the top of the head and then braid the remaining hair in a queue.
