More murderous humans? Killing and enslavement? Speculation. It <i>is</i> known that Neanderthals would slaughter and eat their own kind during a hard winter. And that when Neanderthal encountered the more elegant and graceful arrow and spear point flakes of the modern human, they attempted to imitate them - by chipping an entire nodule down to make one point. Not the correct method which is flaking dozens of good points off of one nodule. Not so good with technology, Neanderthals.<p>And there were never many Neanderthal at all, at any time. Not a successful species really. It takes no fiction of murder and enslavement to explain them away. Intermarrying would do it handily, with the overwhelming population of Homo Sapiens spreading through their territory.