Mammoth Kill Site (IMAGE) University of Wyoming Caption Participants in the University of Wyoming's Archaeological Field School work at the site of a mammoth kill near LaPrele Creek in Converse County, Wyo., during the past summer. A new study by UW researchers supports the hypothesis that hunting by humans led to the extinction of mammoths and other large mammals in the Americas between 12,600 and 15,000 years ago. Credit UW Photo Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.