piece, in which case the larger piece may be called the core and the smaller pieces the flakes. The prevalent usage, however, is to call all the results flakes, which can be confusing. A split in half is called bipolar flaking. Consequently, the method is often called "core-and-flake". More recently, the tradition has been called "small flake" since the flakes were small compared to subsequent Acheulean tools.The essence of the Oldowan is the making and often immediate use of small flakes. Another naming scheme is "Pebble Core Technology (PBC)":Pebble cores are … artifacts that have been shaped by varying amounts of hard-hammer percussion. Various refinements in the shape have been called choppers, discoids, polyhedrons, subspheroid, etc. To date no reasons for the variants have been ascertained:From a functional standpoint, pebble cores seem designed for no specific purpose. However, they would not have been manufactured for no purpose:Pebble cores can be useful in many cutting, scraping or chopping tasks, but … they are not particularly more efficient in such tasks than a sharp-edged rock. The whole point of their utility is that each is a "sharp-edged rock" in locations where nature has not provided any. There is additional evidence that Oldowan, or Mode 1, tools were used in "percussion technology"; that is, they were designed to be gripped at the blunt end and strike something with the edge, from which use they were given the name of choppers. Modern science has been able to detect mammalian blood cells on Mode 1 tools at Sterkfontein, Member 5 East, in South Africa. As the blood must have come from a fresh kill, the tool users are likely to have done the killing and used the tools for butchering. Plant residues bonded to the silicon of some tools confirm the use to chop plants. Although the exact species authoring the tools remains unknown, Mode 1 tools in Africa were manufactured and used predominantly by Homo habilis. They cannot be said to have developed these tools or to have contributed the tradition to technology. They continued a tradition of yet unknown origin. As chimpanzees sometimes naturally use percussion to extract or prepare food in the wild, and may use either unmodified stones or stones that they have split, creating an Oldowan tool, the tradition may well be far older than its current record. Towards the end of Oldowan in Africa a new species appeared over