Lab tests showed the tusk came from a mammoth. Both mammoths and mastodons lived in North America during the Ice Age, but mammoths appeared first. Tusks and teeth from a mastodon were found in 1958 in Granger, a lower Yakima Valley town about 20 miles south of Moxee. Mammoths are believed to have stood about 14 feet tall at the shoulder and weighed up to 8 tons. Researchers around the world continue to try to determine what killed off mammoths and other prehistoric animals.
Theories range from changes in climate to hunting by humans to infection and disease.