Prehistoric extinctions may have been caused by climate change

Science : For at least the past 40 years, hunting by humans on the North American continent was believed to be responsible for the extinction of mammoths and other large mammals some 11 000 years ago. A new study by Matthew Boulanger and R. Lee Lyman of the University of Missouri–Columbia, however, finds that climate change is the more likely culprit. Looking at databases of radiocarbon dates of megafauna and Paleoindian remains in northeastern North America, the researchers found that most of the megafauna had already died off before humans had even arrived. They propose instead that climate and environmental stresses caused by a 1300-year-long cold snap probably played a major part in those mammals’ demise.