The discovery of butchered and modified bones of extinct Pleistocene fauna from Old Crow Flats, Yukon Territory, and the Dutton and Selby Sites, Colorado, provides some of the earliest evidence for man in the New World. However, the significance of these discoveries rests entirely on the ability to determine whether these remains were modified by man. The results of experiments of elephant butchering, bone fracturing, and bone tool manufacturing support the hypothesis that these modified bones can be used to identify the presence of cultural activities. -- AATA