Woolly Mammoth (IMAGE) University of Hawaii at Manoa Caption The woolly mammoth was one of the large mammals that became extinct in North America at the onset of the Younger Dryas approx. 13,000 years ago. Credit Image of Woolly Mammoth at the Royal BC Museum, Victoria, British Columbia courtesy Wikipedia Commons 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.