Long before causing today’s animal losses, people may have been a primary cause of extinctions during the last Ice Age. A study of 177 large mammals (weighing more than 10 kilograms) that went extinct between 1,000 and 132,000 years ago concludes that humans, not changes in climate, may have been the main factor in driving the animals over the brink. Changes in regional temperature and precipitation were weakly linked to extinction hot spots, while the presence of modern humans was a stronger predictor of extinction rates. Thirty percent or more of large mammal species disappeared from most areas in which modern humans were the first hominids present, Danish researchers report in the July 22 Proceedings of the Royal Society B.