Neanderthal fat factory: 125,000 years ago, early humans systematically boiled bones

It takes a few weeks, but eventually, you die from the effects of rabbit starvation. First, your heart rate slows, your blood pressure drops, and after a few days, you experience headaches and fatigue, then diarrhea, and then death. There's only one way to escape: fat.

Rabbit hunger is the term used to describe excessive protein poisoning. It develops when a person eats nothing but lean meat, such as rabbit.

People in traditional hunter-gatherer groups, such as the Indigenous peoples of North America, still experienced rabbit hunger at the beginning of the 20th century. They would have been unable to cope with dietary recommendations that might be appropriate for industrialized societies. They gave the lean cuts, the steaks, and roasts of thigh and shoulder to the dogs, or simply left them alone. They wanted the fat.

125,000 years ago, all humans on earth lived as hunters and gatherers. In Europe, it wasn't yet anatomically modern humans, Homo sapiens, but the Neanderthals. They are still often widely considered cognitively challenged. Yet they clearly knew the value of fat—so much so that they laboriously boiled it from animal bones and perhaps even stored it for lean times.

At least, that's the hypothesis of archaeologists who discovered tens of thousands of crushed animal bones and traces of fire during an excavation in Germany. Lutz Kindler and Sabine Gaudzinski-Windheuser from the Leiza Archaeological Research Center and the University of Mainz, along with an international group of colleagues, have documented their findings. Their article on the Neanderthal fat factory was published in the journal "Science Advances."

This is not the first finding they have made at this site that refutes the image of the dumb Neanderthal.

Ten kilometers south of the city of Halle in Saxony-Anhalt lies the Geisel Valley. Where lignite was mined until a few decades ago, a 19-square-kilometer artificial lake now stretches.

There was plenty of water here 125,000 years ago, too, but the lakes were naturally formed and not the result of mining, as they are called today. It was a warm period, and the climate was similar to today's. Horses, red deer, aurochs, forest elephants, and cave lions roamed the open landscape.

In Neumark-Nord, archaeologists excavated several sites during open-cast mining and later during renaturation. They write that the entire former landscape is preserved in the earth's layers. No bones of the former inhabitants of this area, the Neanderthals, have been found here. Nevertheless, they left behind traces that testify to previously unknown abilities and activities of these early humans.

The archaeologists found evidence that Neanderthals hunted and butchered forest elephants, animals weighing up to 13 tons, each of which provided more than 2,000 daily rations of meat for an adult. When hunting fallow deer, they apparently even got very close to their prey, as evidenced by spear marks on the animals' bones. And they apparently even deliberately altered the landscape through the targeted use of fire.

This suggests considerable cognitive abilities, ecological understanding, and planning skills – and refutes the image of the strong but cognitively underdeveloped early human. Large animals can only be hunted in groups. Coordinating this group hunting requires communication. Neanderthals communicated with each other not only through grunts, but also with a form of language – this is now considered relatively certain.

That Neanderthals also hunted cave lions – and thereby risked considerable injury – is known from another site in Germany; in a rare stroke of luck, their weapons, some of which were made entirely of wood, have been preserved.

The latest findings from Neumark-Nord also confirm that Neanderthals acted in groups, in a coordinated manner and perhaps even with foresight and planning.

Kindler, Gaudzinski-Windheuser, and colleagues examined a unique collection of nearly 120,000 animal bones and 16,500 flint artifacts scattered over an area of ​​approximately 50 square meters. The artifacts indicate that Neanderthals manufactured sharp tools at this site. The scientists also found traces of fire .

Above all, the bones are striking: They come from approximately 170 large animals—horses, red deer, aurochs—and many of them were evidently intentionally chopped into very small pieces while still fresh. Not all skeletal parts occur with equal frequency—but that would be expected if whole animals had been deposited or dismembered here. It is also striking that few foot bones and ribs were found, and instead, mostly long bones, jaws, and skulls. What these bones have in common is their high fat content.

Long bones have a kind of tube inside, the marrow cavity. The bone marrow within is relatively easy to extract and is extremely nutritious. But even bones without this tube contain bone marrow; it is distributed in the cavities of the so-called cancellous bone. To extract it, the bones must be cut and heated—and that, the authors write, is exactly what the Neanderthals did at this location.

The practice is well documented by ethnographic examples; members of the First Nations in Canada, for example, still know the recipe today. However, they use metal cooking pots. Neanderthals didn't even know ceramic vessels. And only a few bones show traces of heating; direct evidence of cooking has yet to emerge, the authors admit.

"Cooking leaves no visible traces of heating, so that's not an argument against it," Alan Outram wrote in an email in response to a request for comment. Outram was not involved in the study; he's an archaeozoologist at the University of Exeter in England and thus a specialist in researching human-animal relationships in the past using animal bones. Electron microscopic methods exist to detect low cooking temperatures in bones, but they don't work well with material of such great age. The crushed bones also speak for themselves: "It's quite plausible that animal carcasses were processed into fat here."

This is certainly possible even without sturdy cookware. The authors of the paper mention leather or birch bark as possible materials for cooking aids, and Outram confirms: "You can also heat water to about 100° Celsius in things like bags. I've even seen people cooking over a fire with very thin plastic bags."

Another possibility is heated stones placed in buckets or pits lined with waterproof clay. Indeed, some pebbles with signs of heating have been found in Neumark-Nord. Outram cites an example from South Dakota, where bone fat was extracted using this method about 1,000 years ago.

"If the bones are well ground, the fat separates quite quickly," explains Outram; therefore, hours of cooking are neither necessary nor efficient, as it consumes a lot of fuel.

As mentioned, some bones and thus animal body parts are underrepresented. Kindler and colleagues interpret this to mean that humans apparently transported animals already partially dismembered to this area. The number of 172 very large animals argues against this being a one-time event. The researchers' hypothesis is therefore that after each hunt, perhaps seasonally depending on the species, the Neanderthals first stored the surplus in storage pits. Only after some time did they bring the bones to this location to extract marrow and fat.

Kindler and his colleagues admit that storage is speculation. Outram is also more skeptical about this aspect: "I'm not sure it would work. If the winters weren't very cold, as described, the prey might rot. The Inuit store meat and bones for fat extraction, but they do so under sub-freezing conditions."

If this storage could be proven for Neanderthals, it would be an important contribution to a better understanding of their cognitive abilities. However, the authors' arguments for storage are less strong than those for fat storage, says Outram.

Why the Neanderthals became extinct about 30,000 years ago remains unclear. However, based on current knowledge, ignorance of rabbit hunger is unlikely to have been the reason.