First recognizable humans

Recognizing the first human is not a straightforward process as it depends on how we define the term "human". For example, it used to be believed that tool-making was a defining feature of humans, but we now know that this behaviour was already happening over 3 million years ago. If we equate "human" with membership of the genus Homo, then at least three early species are known from around 2 million years ago: Homo habilis, Homo rudolfensis and Homo erectus. Some experts believe that the first two of these species resembled the non-human Australopithecus more closely, and it was only H. erectus that exhibited significant human traits such as smaller back teeth, a less robust jaw and a more humanly-shaped skeleton, in which case it is this species that should be considered the first "true" human.

The earliest known hominins (human-like species), meanwhile, date back much further. Orrorin tugenensis found in Kenya and announced in December 2000, has been dated to c. 6 million years. While Sahelanthropus tchadensis, found in 2002 in Chad, is estimated to be between 6 and 7 million years old. It ought to be noted that both these discoveries are quite incomplete, so we need further evidence to place them more firmly on the human family tree.