Neanderthal Brains, Human BrainsThere’s a lot of debate around the similarities and differences between humans and Neanderthals. Were Neanderthals truly a different species from humans, or a different type of the same species? Were they adaptive, cultural innovators like humans, or were they just the dumb cavemen often depicted? Their brains were big like ours… but did they see the world in the same way?

As it turns out a newborn human’s brain is extremely similar to a newborn Neanderthal’s brain. Both are elongated, allowing them to move through the birth canal. (And both come at a cost to mothers: getting those big heads out makes for painful childbirth in both groups.)  But by age 1, marked differences become clear. The human brain becomes more globular, less elongated, while the Neanderthal brain stayed elongated.

Brain shape and size don’t determine intelligence or creativity, but the authors of a new study suggest that the “globularization” of the human brain shortly after birth reflects important and extensive internal brain changes that make the human brain different from the Neanderthal brain. According to the study authors, this likely means that Neanderthals saw the world in a very different way than their human neighbors, and than we do today.

Still, early man and late Neanderthal found enough in common to mate. A couple of years ago, a Neanderthal/human genome project found that if your family is (originally) from Europe or Asia, chances are that between 1% and 4% of your genetic code is Neanderthal.

This fact seems to support the theory that when Neanderthals became extinct around 28,000 years ago, it’s because they got absorbed into the growing human population. That’s not a universal belief, though: there are other ideas about why the Neanderthals disappeared. There’s even some evidence that humans not only outsmarted, but outfought Neanderthals–actively killing them off to become the sole survivors in the battle for evolutionary precedence.