Evidence of human existence (early hominids) in what is now called China have been traced back to 200,000 years ago. The Paleolithic period in China was similar to that seen in other parts of the world. People were primarily nomadic hunters and gatherers. The implements that they used were sharp stones crudely made by percussion. The Mesolithic period was marked by the art of polishing better quality stones and they developed a variety of tools, making not only stone weapons and animal bone needles, but also bows and arrows. Gradually they transitioned to a semi-settled life with small groups of people living in communities.