The branch of hominines, that to which we belong, presents an essential characteristic : whereas all the other animal and vegetable branches have a tree structure, our consists only of one simple line : the species followed one another without never separating. At least, with an exception near : at a certain time coexisted Homo Sapiens, from which we go down, and the man of Neandertal, disappeared without successor.
However it is a thing which no biologist understands in the evolution : the man of Neandertal was trained well better than our ancestor : much more muscular, more resistant to the cold and equipped with larger limps cranial. More resistant to the cold, it's the strangest thing : at that time of cold, the natural selection would have to privilege the survival of Neandertal with our. And yet, we are here... The only correct assumption currently seems to be that of a massacre. Our ancestor would have eliminated itself Neandertal. It would be the first genocide of the history...