There is evidence to suggest that Homo neanderthalensis and Homo sapiens coexisted for approximately 35 to 40,000 years (Fagan 2010), between approximately 60,000 and 25,000 years ago, when they finally disappeared (Gibbon 2001). Anthropologists still don't know exactly what caused their extinction. This article will analyze three main theories about the Neanderthal extinction. The first theory is that of competition, according to which Homo sapiens and Neanderthals had to compete for resources, which ultimately led to their demise. The second theory I will discuss is climate change, which claims that Homo sapiens lived while Neanderthals died because they were better adapted to the climate. The last theory I will discuss is the possible “absorption extinction” theory that Neanderthals interbred with Homo sapiens and became a single species. In this article I will also compare the technologies and diets of the two species. Additionally, I will examine the anatomical relationship between Neanderthals and Homo sapiens, how their shape and size differed, and whether this gave an advantage to one side or the other. My thesis for this article will assert that Homo sapiens and Homo neanderthalensis had coexisted, but that the disappearance of Neanderthals in Eurasia was due to the appearance of the more culturally advanced and genetically superior Homo sapiens, and the failure of Neanderthals to adapt to a changing climate.HistoryIn recent years, Homo Neanderthalensis were considered "subhuman brutes", but are now considered a different species from ours (Balter 2001). Neanderthals were a branch of the genus Homo that evolved in Eurasia at least 200,000 years ago (Fagan 2010). The first Néand... in the middle of the article... would be impossible. Conclusion This article has shown how Homo sapiens had several advantages over Neanderthals, including better diet, better tools, and simply better luck. Neanderthals were unable to survive the harsh climates they were immersed in and eventually became extinct. In this article, I examined how Homo sapiens and Homo neanderthalensis had coexisted, but the disappearance of the Neanderthal ius was due in part to the appearance of the more culturally advanced and genetically superior Homo sapiens. Although the how and why of the Neanderthals became extinct, it is clear that Homo sapiens played a role in their demise. Over the last hundred and fifty years that we have studied humans, we have seen them evolve from savage brutes to respectable contemporary Homo sapiens. If we weren't lucky in the past, Neanderthals could study us today.