The use of tools by early humans was partly a process of discovery and of evolution. Early humans evolved from a species of foraging hominids which were already bipedal,^[19] with a brain mass approximately one third of modern humans.^[20] Tool use remained relatively unchanged for most of early human history. Approximately 50,000 years ago, the use of tools and complex set of behaviors emerged, believed by many archaeologists to be connected to the emergence of fully modern language.^[21]