Early humans shed hair to avoid bug bites: biologists
From CBC News
Last Updated Mon, 09 Jun 2003 18:59:37
LONDON - A new theory proposes early humans evolved smooth skin compared to our furry ape cousins to show they were not infested with blood-sucking insects.
Biting flies and other disease-carrying parasites live in fur. By shedding fur in favour of fire, shelter and clothing that humans controlled, hairlessness became cleaner than a permanent layer of fur, the researchers say.
Attractiveness of facial hair may explain why it persistsThe generally accepted reasoning for hairlessness has been that it evolved to control body temperature in hot climates. One problem with the climate theory is that being furless is an advantage when the sun is out, but it becomes a disadvantage at night, according to evolutionary biologists.
“Hairlessness would have allowed humans to convincingly ‘advertise’ their reduced susceptibility to parasitic infection and this trait therefore became desirable in a mate,” said Prof. Mark Pagel of the School of Animal and Microbiological Sciences at the University of Reading.
“Facial and head hair can be explained by their continued importance in sexual attraction and selection,” he added in a release.
He notes pubic hair poses a challenge to the theory, but the hairs may enhance the pheromone signals during mate selection.
Pagel and his colleague Sir Walter Bodmer of Oxford University say their theory could be tested by seeing if people who live in regions with more disease-carrying parasites are less hairy than those who live elsewhere.
The study will appear in The Royal Society journal, Biology Letters.