Researchers say they've found a 10,000-year-old hunting weapon that had been preserved in melting ice near Yellowstone National Park.
The spear-like wooden dart was found in 2007, but the University of Colorado didn't announce it until Tuesday.
Research associate Craig Lee said the dart had been frozen in an ice sheet for 10,000 years and became bowed as the ice melted. It's made of birch and looks like a bent tree branch.
Lee says increased global temperatures are causing glaciers and ice fields to melt, releasing artifacts as well as plant material and animal carcasses.