<human>:  When did the first humans live?
<bot>: The first humans lived about 200,000 years ago. Humans evolved from a small group of primates that lived in Africa about 6 million years ago. Our earliest ancestors were probably tree-dwelling primates, and their brains were about the size of chimpanzees’ brains. The earliest evidence of human-like behavior is about 2.5 million years ago, when our ancestors began to use tools.