Grasshopper Glacier is a small high-elevation glacier in Montana’s Beartooth Mountains that became famous for the tens of millions of grasshoppers preserved in its ice, including specimens identified as Melanoplus spretus, the extinct Rocky Mountain locust. The insects were likely carried into the alpine zone by severe storms and frozen there for centuries or longer. The glacier also illustrates rapid alpine retreat: once more than 5 miles long in the early 20th century, it had broken into several smaller glaciers by 2007. Lower snowfall, higher temperatures, and difficult access have made recovery harder even as exposed specimens decay, giving the site unusual scientific value as both a biological archive and a sign of environmental change.