In October 2010, during construction of Ziegler Reservoir for Snowmass Village, a bulldozer operator unearthed the remains of a juvenile Columbian mammoth. Scientists from the Denver Museum of Nature and Science arrived, and over the following ten months conducted what would become the museum’s largest-ever fossil excavation. Dubbed “Snowmastodon” by museum crews, this dig yielded a treasure trove of well-preserved Ice Age fossils. Through the course of excavation, 6,000 megafauna bones and teeth along with over 30,000 bones and teeth belonging to smaller animals were uncovered. In total, the excavation produced 52 species of Ice Age vertebrate animals. Discovery highlights include 36 American mastodons, 4 Columbian mammoths, 3 Jefferson’s ground sloths, 10 Bison latifrons, as well as Ice Age species of horse, camel, deer and much more. Snowmastodon also yielded approximately 100 plant species in addition to more than 100 species of invertebrate animals such as fresh water mollusks and insects. The plant and invertebrate species recovered from the site have provided a unique understanding of the ecology of the area during the last interglacial period. These preserved remains of an entire high-elevation Ice Age fossil ecosystem are one of the most significant fossil discoveries ever made in Colorado.
Thus far, four-dozen scientists from over 20 different institutions have conducted research on the geology, flora and fauna of Ziegler Reservoir. Their findings have provided a wealth of information about past climatic changes and important insights into the biogeography of plants and animals within the Rocky Mountains from 150,000 to 45,000 years ago. This discovery in Snowmass Village has forever changed the understanding of alpine life during the Ice Age.