Matthew Waller, director of the Stable Isotope Facility at the University of Alaska Fairbanks, was part of a group of scientists who discovered how to use layers of minerals in mammoth tusks to trace where these animals once lived. Biologists have begun analyzing the layers of minerals that accumulated every day on the outside of mammoth tusks, and as researchers study more tusks, they hope to answer some of the biggest questions about how the massive mammals thrived for hundreds of thousands of years. They are also collecting evidence about how the mammoths became extinct at the end of the Ice Age. According to a report by Carl Zimmer in the New York Times, Matthew Waller and his colleagues discovered how to use mammoth tusks to track the places where the animals lived throughout their lives. They did this by measuring an element called strontium, which is found in trace amounts in plants that animals eat. If a mammoth spent a day grazing somewhere that had a lot of strontium in the soil, the cone of minerals it grew that day would have a high level of strontium, new information through which scientists seek to understand the evolution of these creatures and study the real causes of their extinction. (Photo courtesy of the New York Times)
