The Acheulean Tradition first began in Africa and there it is well-defined and most diverse when compared to other regions where it eventually spread to. HAND AXES are the most typical bifacial tool associated with this period. Different from the bifacial tools from the earlier Oldowan Period, Acheulian tools are fashioned from large flakes as opposed to using a whole cobblestone as the core. Along with handaxes, other bifacial tools that are Acheulian are CLEAVERS (large handaxes with a flat top) and PICKS (robust elongated, trihedral tools). Other stone implements found at Acheulian sites include smaller flake tools.
The first hominids to live outside of Africa were the primitive humans Homo erectus. Around 1.8 million years, these hominids spread through south Asia keeping to the tropical zones to which they preferred. They eventually colonized temperate regions of Europe and North China less than one million years ago but never reached Australia or the Americas. Unlike the later Neanderthal species, Homo erectus avoided frozen and sub-Artic regions of the world. With the arrival of Homo erectus in Europe, stone tool technology took a step back as both Oldowan style pebble tools and later Acheulean tools are found in the habitation layers, existing after the more refined Acheulian technology was practiced in Africa. The precise date for Europe's initial human occupation is not known and human fossils before 700,000 years in Europe are too scarce to base any theory on. We know that between 700,000 and 400,000 years ago, the first handaxes were used in Europe. Debris from both occupied sites and kill sites show evidence of butchered large game animals and stone tool manufacture of both, bifacial handaxes and smaller flake tools modified from crude secondary flakes.
The actual function of handaxes is debated. Some suggest they were not used as a chopping tool but for butchering game. Scientists have shown that these tools exhibit wear common to butchery uses. Other scientists have theorized they were thrown into a herd as a deadly spinning projectile. Probably the most interesting theory and one that explains why many unworn and pristine condition tools have been found abandoned is that of the tool's use not as a tool at all but as an aid to sexual attraction. Possibly, males used techniques of being able to fashion symmetrical stone axes to attract females and demonstrate they were the most capable individual for survival and support of a family. If you were a primitive human able to make a large symmetrical hand axe, this would show you were genetically superior and an excellent candidate for mating. There is much evidence that contradicts this theory but it sure is quite an interesting hypothesis. Based on the varieties of utilitarian hand axe designs, and not only obvious wear from use but actual well-thought flaking designs to best fit ones hand, there's really little doubt that these stone tools were relied upon on a daily basis for primitive man's existence.