When fossilized Neanderthals (or “Neandertals” if you prefer) were discovered in caves in Europe back in the mid-1800s, it was assumed that they were stupid, ape-like brutes. Indeed, they did possess compact, muscular bodies with short legs.

We’ve learned in the past few decades that our stereotype of Neanderthals was wrong. These were fully human creatures who hunted with spears, created art, made boats, fished, ceremonially buried their dead, and almost certainly spoke to one another. They were as advanced as any other hominid of the time period.

They were the related to, but not direct descendants of, Homo Erectus, which had migrated out of Africa and into Eurasia over a million years ago. By the time they got to Europe, they had evolved.

Neanderthals, alone, owned Europe for nearly half a million years, through the course of multiple ice ages.

The living wasn’t easy. Much of their diet was the resident megafauna of mammoths, bison, elk, and mastodons, and whatever other protein they could kill and eat. Their stone-age existence was probably not much different than the pre-Columbian existence of the plains Indians in North America.

“Modern” humans finally arrived in Europe around 45,000 years ago. For about 5,000 years thereafter, or more, the two subspecies shared Europe and shared their cultures.

And shared body fluids. Neanderthal DNA accounts for about 1-2% of today’s human DNA outside Africa.

Neanderthals finally died out. Another way of looking at it, however, is that the newcomers overwhelmed the Neanderthals with their sheer numbers. If a population of, say, 20,000 Neanderthals is absorbed into a population of one million modern humans, the Neanderthal DNA will account for only 2% of the resulting population – without any Neanderthals being harmed in the process.

What actually happened is probably somewhere in the middle. To some extent, Neanderthals were simply absorbed. And to some extent, they were out-competed and even killed.

The visual appearance of Neanderthals is debated. Some scientists contend that they could be dressed in a suit and stroll down Madison Avenue without getting a second look (other than looks from people wondering why anyone would wear a suit these days). Other scientists contend that their heavy brow ridges and musculature would surely merit a second look, regardless of their garb.

But giving a person a second look for his appearance is not the same as shrieking “Yikes, a caveman!” Many modern humans have an appearance that is outside the normal range.

Here’s something interesting about Neanderthals’ appearance that we do know. We know from DNA analysis of their remains that they were light-skinned and probably had blond or red hair.

This should be no surprise. Human skin uses sunshine to manufacture vitamin D. In the northern latitudes, such as Europe, the reduced sunshine results in less manufactured vitamin D. Light skin is a natural adaptation, because it permits more sunshine to penetrate the skin.

Here’s another skin pigmentation fact that did come as a surprise, at least to me. While Neanderthals had light skin for hundreds of thousands of years from living in northern latitudes, light skin in modern humans did not develop until much more recently.

Light skin is a complex phenotype for which no single gene is responsible, but the general view is that the various genes did not produce light skin in modern humans until about 10-30,000 years ago – sometime after the migration of modern humans out of Africa.

That more recent time – 10,000 years ago – barely puts it prior to the advent of agriculture and cities in the Levant.

Moreover, both the recent time of 10,000 years ago for the development of light skin in modern humans and the more distant time of 30,000 years ago put it after modern humans migrated into Europe, the domain of the Neanderthals.

The upshot is this. The meeting between the original Europeans – the Neanderthals – and modern humans was a meeting between light-skinned European Neanderthals and migrating dark-skinned modern humans.

It’s tempting to conclude that the source of the light-skin genes in modern humans was the Neanderthals with whom they interbred after arriving in Europe. But paleo-geneticists say that’s not the case. The genes for light skin are different between Neanderthals and modern humans, which suggests that the two lines of humans developed light skin independently – but for the same reason of optimizing vitamin D synthesis in northern latitudes.

What’s all this have to do with immigration along the southern border, conservative wins in the German election, and The Aspen Beat? Nothing, but I thought it was interesting.