Sealed for millenniums, Qesem Cave in central Israel is a limestone time capsule of the lives and diets of Paleolithic people from 420,000 to 200,000 years ago. Inside, ancient humans once butchered fresh kills with stone blades and barbecued meat on campfires.
“It was believed that early hominins were consuming everything they could put their hands on immediately, without storing or preserving or keeping things for later,” said Ran Barkai, an archaeologist at Tel Aviv University in Israel.
But not every meal was scarfed down right after a hunt. Dr. Barkai and his colleagues have found that the cave’s earliest inhabitants may have also stored animal bones filled with tasty marrow that they feasted on for up to nine weeks after the kill, sort of like a Stone Age canned soup.
The finding may be the earliest example of prehistoric humans saving food for later consumption, and may also offer insight into the abilities of ancient humans to plan for their future needs. The study was published Wednesday in Science Advances.
Dr. Barkai’s team examined cut marks on nearly 82,000 animal fragments from Qesem Cave, most belonging to fallow deer. The researchers noticed unusual, heavy chop marks on the ends of some leg bones known as the metapodials.
The chop marks “make no sense in terms of stripping off the bone, because at this part of the bone there is no meat and very little fat,” Dr. Barkai said.
Usually, stripping the hide from a fresh bone requires minimal force, he said. But the heavy chops indicated that the processing used more force than should have been necessary.
“We had a hypothesis that these unusual chop marks at the end of the meatless bones had to do with the removal of dry skin,” he said. But why were they doing that?
The team concluded that the ancient hominins, who shared features with Homo sapiens and Neanderthals but were probably neither, were removing dry skin on the bones to get to the marrow.
That presented another question: If they were after marrow, why not just remove it from the bone when it was fresh? The researchers hypothesized that the chop marks were an indication that the early humans stored the bones so they could eat the marrow later.
To test their idea, the team collected freshly killed deer leg bones and then stored them for several weeks in conditions similar to those inside the cave. After every week, they would break open a bone and analyze the marrow to see how nutritious it still was.
Every time, a researcher would remove the dried skin using a flint flake and then hammer open the bone with a quartzite tool, similar to what the ancient people would have had used. The researcher wasn’t given instructions on how to open the bone.
The team found that the researcher’s chop marks on the older leg bones with dried skin were similar to what they saw in Qesem Cave.
“It was a surprise when we realized that the same marks were generated experimentally,” said Ruth Blasco, a zooarchaeologist at the National Research Centre on Human Evolution in Spain and lead author on the study. “The Qesem hominids have demonstrated very modern behavior in their livelihood strategies.”
Their chemical test showed that after nine weeks, the fat in the bone marrow degraded only a little and was still nutritious.
Jessica Thompson, an archaeologist at Yale University, said the paper was a creative approach to reconstructing a past behavior that is notoriously difficult to identify in the archaeological record.
“Their experimental work does a lot to convince me that some of the bones were not very fresh when they were processed, although it is still not clear how common this behavior was,” Dr. Thompson said.
Briana Pobiner, a paleoanthropologist at the Smithsonian National Museum of Natural History, praised the study and said that if this removal of dry skin did leave a unique utchery mark, “it’s now up to us zooarchaeologists to look for these traces in older fossil assemblages to see if we can document a greater antiquity of this food storage behavior.”
As for the marrow, how did it taste? One of the researchers couldn’t resist trying it.
“It is like a bland sausage, without salt, and a little stale,” said Jordi Rosell, an archaeologist at Rovira i Virgili University in Spain. “I can say that its taste was not bad, perhaps a little more rancid in the last weeks, but not bad.”