27.    The Lucy’s Pelt. When men became hairless and how he managed to survive. 
Alfredo Rebora, University of Genoa, Genoa, Italy

Why, of the 193 species of primates, man alone looks glabrous remains a mystery, but the real problem is when the mutation occurred and how hominids managed to survive a substantially deleterious mutation. According to the available evidence, the hairless mutation occurred before the Pan-Homo divergence. Denudation however must have become evident much later. Fur, in fact, was necessary when Australopithecinae moved to the hot savannah where hairlessness would have left them defenseless against the African sun. Furthermore, traces of Homo erectus were found in the Caucasian Georgia where the average winter temperature is 0°C. As, at that time, Homo erectus did not control fire, he could not survive hairless. Homo erectus was hairy, therefore, though probably less hairy than his progenitors. To conciliate an early mutation with a late denudation, we must accept that mutations display their phenotypic effects also progressively. The runaway sexual selection model provides a plausible explanation.