From: Bruce Sherrod >the onset of an ice age would mix the human genome by concentrating > humans in equatorial warmer regions. Then, when the ice age ends, > humans enter a "boom time" economy . The onset of the glaciers was the boom time. At the peek of the ice age the temperate zones contained very large areas of steppe-tundra. The Pleistocene Megafauna and the humans who preyed on them would be at their maximum populations at this time. When the ice receded was the time of stress. See: Cohen, Mark Nathan "The Food Crisis in Prehistory: Overpopulation and the Origins of Agriculture" in the bibliography at my site. Ray Audette Author "NeanderThin" http://www.neanderthin.com