We don't know which species should be classed as 'human'
Some say it is culture that makes us human. Others opt for our morality, language, or even our sense of humour. But putting philosophy to one side, what literally makes us human? Surprisingly, there is no official answer. Science has yet to agree on a formal description for our genus, Homo, or our species, sapiens. It's not for lack of trying. There are actually several suggested definitions for the human genus – and an astonishingly broad range of opinions...