Climate not really what doomed large North American mammals

Evidently, my dear Watson, the climate didn’t do it. Scientists weighing in on a cold case open since the end of the most recent ice age — the massive die-offs of North America’s largest mammals — arrived at that conclusion courtesy of some very tiny clues. The spores of a fungus that thrived in and on those creatures’ dung suggest changes in habitat didn’t cause the extinctions. As a result, it’s looking more and more like humans played a major role.