Neanderthals were running a potentially lifesaving “fat factory” around 125,000 years ago in what is now Germany, a new study finds.

The research, published in the journal Science, reveals that these archaic human relatives had a process for extracting grease from animal bones — and it may have saved them from a lethal condition. The condition, known as protein poisoning or rabbit starvation, happens when humans eat too much protein and don’t get enough fat or carbohydrates. Neanderthals would have likely been at high risk of protein poisoning, as they largely ate meat.

The “fat factory” discovery suggests that hominins, or humans and our close relatives, were practicing resource intensification — getting more utility out of the materials they had available — much earlier than previously thought. Before this analysis, the earliest evidence for resource intensification dated to 28,000 years ago, long after the Neanderthals’ extinction, according to the study. Scientists found the Paleolithic factory after uncovering the fragmented remains of 172 large animals, including horses, deer and cattle, as well as Neanderthal-made anvils and hammerstones. After analyzing the bones, the team found that Neanderthals had first smashed the bones to get to the marrow — a soft, edible tissue inside of some bones — before boiling them to extract the fat. It appears that Neanderthals ate both the marrow and the fat, which would have maximized the amount of food and nutrients they got from an animal carcass.

“It’s surprisingly creative and innovative behavior from Neanderthals,” Osbjorn Pearson, an archaeologist at The University of New Mexico who was not involved in the study, told Live Science. Neanderthals, the closest extinct relative of modern humans, emerged around 400,000 years ago and went extinct around 34,000 years ago. Remains of the archaic humans were first discovered in the 19th century, and much of the archaeological evidence revealed since then suggests that Neanderthals were fairly sophisticated. They made tools, glue factories and possibly even art. While it was known that Neanderthals largely ate meat, little was known about how Neanderthals prepared animal carcasses. “We know a lot about Neanderthal hunting tactics, habits and consumption of meat and bone marrow … but to much lesser degree about all the processes after hunting and butchering,” study first author Lutz Kindler, an archaeologist at the Monrepos Archaeological Research Center and Museum for Human Behavioral Evolution in Germany, told Live Science in an email.