Remarkably, Paleo-anthropologists are not super clear on when the Neanderthals first began to separate themselves from their own ancestors, but the fossil record tells us that Neanderthals were definitely around by about 300,000 years ago. They mysteriously disappeared around 40,000 years ago, as modern humans first began to move into Europe.

However, given the difficulty of interpreting the fossil record, scientists are divided on why these primitive humans no longer walk the Earth. Many believe that modern humans out-competed Neanderthals, eventually leading to the neanderthal extinction. In the end, you’ve got one human population that replaces the other, which historically does not happen in a peaceful manner.