What is clear from the European fossil record is the anatomy characteristic of Homo neanderthalensis disappeared rather rapidly between 50 and 30 ka and that this disappearance coincides with the migration of Homo sapiens into Europe from Africa. Thus, questions about what exactly caused that disappearance are crucially important and stridently contended. There is no evidence of warfare in Europe (or elsewhere) at this time. Therefore, the notion that Homo sapien s actively exterminated Homo neanderthalensis is difficult to maintain. Many scholars believe that the sophisticated symbolic and cognitive capabilities of Homo sapiens combined with their adaptation for hunting a large range of diverse prey allowed them to outcompete Homo neanderthalensis . This point of view is particularly relevant in light of the dramatically shifting climate that was witnessed in Europe around the time that Homo sapien s arrived. That is, Homo sapiens ’ broad subsistence strategy and ability to cognitively adapt to difficult environments may have allowed them to spread quickly and widely during times when the climate shifted dramatically. Homo neanderthalensis , on the other hand, may have had difficulty dealing with these drastic shifts in climate, due to their focus on hunting large game animals. Other researchers suggest Homo sapiens had a demographic, rather than a technological, edge on Homo neanderthalensis . These scholars suggest Homo sapiens maintained larger and more numerous populations and that, over time, the sheer numbers of Homo sapiens simply swamped out Homo neanderthalensis populations, which are thought to be smaller, more spread out, and less numerous. Of course, it is very possible that both of these factors (., technology and demography) acted in concert, resulting in the disappearance of the Neanderthals .