Prehistoric Knives Suggest Humans Competed By Jennifer Viegas, Discovery News Feb. 1, 2005 — A recent excavation of 400,000-year-old stone tools in Britain suggests that two groups of early humans could have competed with each other for food and turf. In the past, anthropologists have argued that only one group of ancient humans lived in Britain, and that these hominids created and used both axes and flake knives, which were made by flaking off small particles from a larger rock, or by breaking off a large flake that was then used as the tool. Some form of prehistoric human had...