Abstract: Tool-making was long considered a capability and behavior unique to humans, and “Man, the tool-making animal” was long used as the fundamental definition of humanity. Today, bipedal locomotion is taken as the most important characteristic of the hominids, while tool making seems to have been relegated to a less important role in human evolutionary history. We now realize that a handful of animals, especially the non-human primates, possess tool-using abilities and, in even fewer cases, the capability to make tools. What is the role of tool-making in the history of human biological and cognitive evolution? How can we differentiate anthropogenic tools from artifact-like objects (especially lithic) created by hominids and other animals? Do archaeologists have the capacity to unequivocally distinguish human artifacts from products made by other primates? Using the examples of fractured stones fabricated by wild bearded capuchin monkeys in Brazil, lithic artifacts left by chimpanzees 4300 years ago in Co?te d’Ivoire, and 3.3Ma BP stone artifacts made by human ancestors at Lomekwi 3, west of Lake Turkana in northern Kenya, this paper points out that human tools are significantly different from similar products created by other animals, and tool-making activities are vital and essential in defining the uniquely human evolutionary trajectory and influencing human cognitive development. Archaeologists should be cautious in identifying and analyzing stone artifacts made and used by early hominids which share some similarities with geofacts and the products of other animals, but should also realize that human tools are unique in many ways because of human planning, imagination, prediction, functional considerations and highly skilled technological control. The development of archaeological research and the advance of modern technology both facilitate the capability to draw a picture of human evolution more precisely and comprehensively.

Key words: Tool-making；Lithic artifacts；Hominids；Primates；Human evolution