OPINION LETTERS

摘要

In her article "Not even a theory to cover our nakedness", Elaine Morgan explores possible reasons why humans lost their thick body hair (19 September, p 28). Surely the simple answer is because we could.rnHair is biologically expensive. It requires valuable protein and energy to make, a lot of maintenance, and can harbour parasites. While the insulation it provides may repay these energy costs by keeping the animal warm when its surroundings are cold, it limits the amount of strenuous activity possible for finding food when the animal is hot.