Like other humans, Neanderthals originated in Africa but migrated to Eurasia long before other humans did. Neanderthals lived across Eurasia, as far north and west as the Britain, through part of the Middle East, to Uzbekistan. Popular estimates put the peak Neanderthal population around 70,000, though some scientists put the number drastically lower, at around 3,500 females
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Extinction
No one knows exactly why Neanderthals went extinct and why Homo sapiens survived. Some scholars theorize that gradual or dramatic climate change led them to their demise, while others blame dietary deficiencies. Some theorize that humans killed the Neanderthals. Until recently the hypothesis that Neanderthals didn't go extinct but simply interbred with humans until they were absorbed into our species was popular.