The Ultimate Cave People

New fossil [findings] in a cave in France have made us rethink a decades-old idea in paleoanthropology. This information comes from the Grotte Mandrin cave in Mediterranean France, that contains sediments from 56,800 – 51,700 years before the present. These sediments are arranged in layers, just like all geologic strata, but because much of the sediment stays within the cave instead of being eroded away, they are able to preserve finer time intervals.

Figure 1 from the paper, showing the cave from outside and in.

Inside this cave, and in each layer, were teeth from “anatomically modern humans” (people like us) and Neanderthals, and stone tools of different kinds. Because of the difference in abilities between the two types of humans, the stone tools they produced look different.

The layers of the cave and the teeth and tools found in each. Image by Ludovic Slimak.

I want to pause here for a moment and talk further about Neanderthals. They get a bad reputation as being ‘inferior’ to modern humans because of the idea that modern humans outcompeted Neanderthals any time the two came into contact. The two species may have fought when they saw each other sometimes, but there’s also evidence of gene flow between the species, so their contact didn’t always end in a battle.

The fossil evidence in the Mandrin cave shows that modern humans and Neanderthals were living in the same cave at different times. Caves provide natural shelter from wind, rain, and animals, so it seems logical that people would want to stay in one. Because the alternating layers show a pattern of Neanderthal->Modern humans->Neanderthal->Modern humans staying in it, it tells us that this cave was an important ‘pit stop’ for modern humans migrating out of Africa and into Europe. And because there is this pattern of alternating species, it shows that the appearance of modern humans didn’t automatically mean doom for the Neanderthals.

So why did Neanderthals die out? Possibly changes in climate decreased their population (they were adapted to colder climates), and possibly modern humans were just intolerant to competition. More data, especially from caves, will help us find out.

Caves and Tools

In Morocco (Africa) 120,000 years ago, a wildcat, a jackal, and a fox met in a cave. What were they doing there? And what do humans have to do with it?

Today’s post is about [human culture]. And fossils. Most of what I post here is about what fossils can tell us about how, when, and where an animal lived. Fossils can tell us so much about the biology of now extinct animals. But that’s not all they can tell us. In some cases, the bones record what happened after the animal died.

The cave location in Morocco, Africa. (Figure 1b from the paper)

The Contrebandiers Cave in Morocco has sediment layers inside that date back to 120,000 years ago. Caves make excellent shelters, so as animals and plants use the shelter or get trapped there, they are fossilized and can be discovered later. Within the Contrebandiers Cave, explorers found the fossilized bones of a golden jackal, sand fox, wildcat, and several cow-like animals.

Some of the animals found at the cave. (Attributions on the image, retrieved from Wikipedia)

But these animals were not just hanging out together, they had been brought there by the humans (Homo sapiens) that lived there at the time. According to the markings on their bones, the animals they hunted and brought back to the cave were skinned in order to make clothing. Clothing itself does not fossilize easily because the fur it was made from breaks down very quickly.

An example of how ‘spatulate’ scraping tools were made and how they were used. (Figure 4 from the paper)

The animal bones weren’t the only evidence of skinning. There were tools present in the cave as well. Tools made from animal bones and shaped in specific ways by ancient human hands. Humans today still use similar tools and methods for skinning, so we don’t have to guess what the tools were for. This cave preserves the oldest evidence of formal bone tools and the production of clothing by modern humans (Homo sapiens)in Africa.

Side note: This is the first scientific paper I’ve read that has an “Inclusion and Diversity” statement at the end. The authors state, among other important points, that they ‘actively worked to promote gender balance in our reference list.’ I am grateful that the journal includes that statement and for the author’s work.