Neanderthals living 125,000 years ago in what is now modern-day Germany may have extracted and eaten fat from animal bones through an organized food preparation process that scientists describe as a ‘fat factory.’

While excavating the site of a former lake landscape called Neumark-Nord, archaeologists discovered thousands of bones from at least 172 large mammals, along with flint artifacts. The bones, which date back to an interglacial period in which Neanderthals lived, were from animals like red deer and horses, according to a study published on July 2 in Science Advances.

While many of the bones that contained less bone marrow were spread out across the archaeological site, researchers observed that many of the marrow-rich bones were located in clusters — sites they call ‘fat factories.’ 

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A picture taken on September 6, 2021 shows the reconstruction of the face of the oldest Neanderthal found in the Netherlands, nicknamed Krijn, on display at the National Museum of Antiquities in Leiden. (BART MAAT/ANP/AFP via Getty Images)

Researchers believe our extinct ancestors used tools to smash the bones into small fragments and then boiled them for hours. The grease, which then floated to the surface of the water, could be skimmed off the top and eaten — providing a calorie-dense food source for the archaic people.

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Prior to this, evidence of the practice had only dated back to 28,000 years ago, according to the research.

FILE PHOTO: A red deer stag is pictured here. The bones, which date back to an interglacial period in which Neanderthals lived, were from animals like red deer and horses. (Getty Images)

“Neanderthals were clearly managing resources with precision — planning hunts, transporting carcasses, and rendering fat in a task-specific area,” Dr. Lutz Kindler, the study’s first author, said. “They understood both the nutritional value of fat and how to access it efficiently — most likely involving caching carcass parts at places in the landscape for later transport to and use at the grease rendering site.

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Fat was a “life-sustaining” resource for Neanderthals, especially during the winter and spring seasons when carbohydrates were scarce. Their diets consisted largely of animal protein, and consuming lots of protein without other nutrients could lead to a sometimes deadly condition called protein poisoning, the research noted.

FILE PHOTO: Tools used in an archaeological excavation are seen here. (Getty Images)

“The sheer size and extraordinary preservation of the Neumark-Nord site complex gives us a unique chance to study how Neanderthals impacted their environment, both animal and plant life,” Dr. Fulco Scherjon, data manager and computer scientist on the project, said. “That’s incredibly rare for a site this old—and it opens exciting new possibilities for future research.”

In recent years, scientists have also discovered that Neanderthals went diving for seashells that they could chip with stone hammers into thin and sharp cutting edges. Similarly, another study suggested Neanderthals may have buried their dead with flowers.

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Researchers Lutz Kindler and Wil Roebroeks did not immediately respond to Fox News Digital’s request for comment.