Not only do we possess an abundance of uncivilised cousins, once upon a time we had quite a few brothers and sisters as well. We are used to thinking about ourselves as the only humans, because for the last 10,000 years, our species has indeed been the only human species around. Yet the real meaning of the word human is ‘an animal belonging to the genus Homo’, and there used to be many other species of this genus besides Homo sapiens.
