the overkill hypothesis have the most support, with evidence weighing towards the overkill hypothesis. Although not mutually exclusive, which factor was more important remains contested. Where humans appeared on the scene, megafauna went extinct; but at the same time, the climate was also warming. Large body size is an adaptation to colder climes, so a warming climate would have provided a stressor for these large animals; however, many fauna simply evolved a smaller body size over time. There is overwhelming archaeological evidence that humans did indeed hunt some or many of the now extinct species, such as the mammoth in North America; while evidence of hunting is necessary for the overhunting hypothesis, it is not sufficient to prove that human hunting drove the extinctions. The primary cause of Pleistocene megafauna extinctions may vary among regions and species (see below). Effects and causes by continent Africa Background and scope While North America was most notably impacted by the Pleistocene Megafaunal extinction, Eurasia, Africa and the Insular regions were also affected and experienced some extinction towards the end of the Pleistocene period. Megafaunal losses are poorly understood on continental Africa during both the Late Pleistocene and the Holocene periods. During the late Pleistocene and early Holocene period an estimated breadth of 24 large mammal species, of greater than 45 kg, were lost from continental Africa. These losses are best understood to have occurred between 13,000 and 6,000 years ago. The species of megafauna which were lost in continental Africa are best understood to have been grazers who lived on grasslands. However, other sources report that over 27 species were lost in the last million years. Sources vary in the breadth of the issue, however it is clear that significant biodiversity loss occurred in Africa. Anthropogenic involvement At sites in Africa such as Olduvai, Olorgesailie, Kariandusi, Hopefield, Islmilia, and the Vaal River gravels most genera found were found in stratigraphic association with hand tools wielded by early human ancestors. These artifacts were from Acheulean origins. Acheulean tools include handaxes made from stone. These hand tools were made with a distinctly pear shaped morphology. Homo erectus was thought to wield these hand tools for a variety of purposes. Hand axes could be used to butcher and skin game, cut, chop, scrape, cut other instruments, digging in soil, cutting wood, cutting plant material. These tools were first discovered in 1847. These handaxes have been discovered