At Qesem Cave in Israel, Neanderthals or early Homo sapiens appear to have stored marrow-rich deer bones for several weeks, relying on the bones and their outer layer of dried skin and flesh to keep the marrow relatively fresh — like storing leftovers in Pleistocene Tupperware.
Based on the cut marks on the bones, people extracted the marrow after a few weeks, when the bones and their covering of skin and tendons had had time to dry out. That suggests the people who lived at Qesem were planning ahead for their future needs — which is one more piece of evidence that Neanderthals and the earliest members of our own species were smarter than we've often given them credit for.
Stone Age Tupperware
People of various groups have lived at Qesem Cave off and on for hundreds of thousands of years. Archaeologists haven't found hominin fossils at the site so far, but in the oldest layers of artifacts, they've unearthed oval and pear-shaped handaxes in the Acheulian style — a stone calling card of Homo erectus or their descendants, Homo heidelbergensis. In layers dating from 300,000 to 200,000 years old, the stone blades and scrapers belong to a set of stone tools culture called the Acheulo-Yabrudian, which has turned up at Neanderthals and early Homo sapiens sites.
Deer bones from those layers — especially the metapodials (the long bones of the feet), which are rich in bone marrow — showed the telltale signs of people cracking them open to get at the marrow inside. Most of the metapodials at Qesem were broken into fragments, and many were pitted and flaked as if they'd been hit with a hammerstone. Many also bore cut marks, probably from when the ancient people cut away the skin and tendons to get to the bone underneath.
To better understand exactly what Pleistocene people at Qesem were doing with the deer bones, Tel Aviv University archaeologist Ruth Blasco and her colleagues tried a little Stone Age meat processing of their own. They gathered up a set of fallers with metapodials and stored them for a few weeks in conditions similar to those at Qesem. Every week, the archaeologists skinned and cracked open a few of the bones.
At first, they only needed to make a couple of quick cuts to sever the tendons from the ends of the bone, and then they could peel away skin and tendons pretty easily. But as the skin and tendons are dried, they become much harder to remove. After the second week, cutting away the soft tissue required making several more cuts along the length of the bone — usually while holding the blade almost flat against the bone — and occasionally even sawing at the tendon. The marks left behind on the bone looked a lot like the marks on many of the Qesem bones.
Fresh bone also breaks differently than dried bone; that's how archaeologists can tell whether a bone was broken around the time of death or sometime afterward. It's an important clue in reconstructing ancient events at Qesem Cave. There, the edges of the bone fragments and the impact points of the hammerstones looked more like what happened when archaeologists cracked open deer bones after a couple of weeks or longer.
In other words, it looked like most of the marrow-rich deer metapodials at Qesem had sat around for at least two weeks, and maybe up to nine weeks, before people cut away the skin, cracked open the bone, and enjoyed a tasty, convenient meal of leftovers.
We had "doggy bags" before we had dogs
Bone marrow is a high-calorie, nutritious food source, and it stores surprisingly well if it's left inside the bone. If the outer layers of skin and flesh are left intact, they provide some added protection from bacteria — again, a bit like the lid on a Tupperware container. Blasco and her colleagues found that marrow kept the most nutritional value for at least three weeks in springtime conditions and as long as nine weeks in autumn conditions. Even after nine weeks, the marrow from a deer metapodial offers about the same energy content, and it would probably have been safer to eat than dried meat.
Anthropologists usually assume marrow is one of the first things people eat after they kill a deer or other prey animal. In some modern hunter-gatherer cultures, hunters pause to eat a quick meal of marrow before hauling the rest of their kill home for processing. At Qesem, though, it looks like people were choosing to bring home marrow-rich bones like the metapodials rather than cracking them open and eating the marrow in the field. The bones that turned up most often in the layers of artifacts at the cave are also tended to be the ones with the most bone marrow (proportional to their weight, at least), and Blasco and her colleagues suggest that there is no coincidence.
The researchers acknowledge that the marks they've seen could technically have been from other kinds of food processing, but marrow storage looks like the most likely option. That kind of planning ahead suggests a much more modern level of cognitive development — or at least planning we've assumed was modern. It turns out we've probably been selling our extinct hominin relatives short.
Science Advances, 2019. DOI: 10.1126 / sciadv.aav9822; (About DOIs).