Tooth enamel provides clues to hunter-gatherer lifestyle of Neanderthals

Newswise — A research project headed by the University of Southampton and conducted by a global team of scholars has provided a captivating insight into the hunting patterns and food preferences of Neanderthals and other human populations residing in Western Europe.

The researchers analyzed the chemical composition present in tooth enamel to reconstruct the way early humans relied on the natural resources in the vicinity of the Almonda Cave network, situated close to Torres Novas in central Portugal approximately a century ago.

As reported in PNAS, their discoveries indicate that Neanderthals in that locality were engaged in the pursuit of relatively sizable game over extensive territories, whereas humans dwelling in the same region several millennia afterward relied on smaller animals within an area half the size.

Due to radioactive procedures, the strontium isotopes present in rocks slowly alter over millions of years, leading to their variation from one place to another, contingent upon the age of the underlying geology. Over time, these isotopic characteristics are transferred from weathered rocks to plants through sediments and further propagate through the food chain until they ultimately settle in tooth enamel.

The archaeologists in this investigation employed a method that involves the use of lasers to extract enamel samples and obtain thousands of distinct strontium isotope measurements along the development of a tooth's crown. They gathered samples from two Neanderthals dating back approximately 95,000 years and from a more recent human who existed during the Magdalenian period, around 13,000 years ago.

Additionally, the researchers examined isotopes in the tooth enamel of animals discovered within the cave system. They assessed oxygen isotopes alongside strontium, which fluctuate seasonally from summer to winter. This approach allowed them to determine not only the regions where the animals roamed, but also the seasons when they were available for hunting.

The team's analysis revealed that the Neanderthals, who focused on hunting large game, likely targeted wild goats during the summer months, while horses, red deer, and a now-extinct type of rhinoceros were available year-round within a radius of roughly 30 kilometers from the cave. On the other hand, the Magdalenian individual had a distinct subsistence pattern, with seasonal movement of approximately 20 kilometers from the Almonda caves to the Tagus River banks. Their diet comprised of rabbits, red deer, wild goat, and freshwater fish.

The investigators estimated the range of the two distinct human populations, exposing disparate outcomes. The Neanderthals procured their sustenance from an area spanning around 600 square kilometers, while the Magdalenian individuals inhabited a considerably smaller territory of roughly 300 square kilometers.

Dr. Bethan Linscott, the lead author of the study, who conducted the research while at the University of Southampton and currently works at the University of Oxford, remarked, "Tooth enamel is formed sequentially, thus providing a chronological record of the geological provenance of the food consumed by an individual."

She added, "With the help of laser ablation, we can detect changes in strontium isotopes over the two or three years it takes for enamel to develop. By matching the strontium isotopes found in the teeth with sediment samples collected from various sites in the area, we managed to trace the movements of the Neanderthals and the Magdalenian individual. The geological makeup in the vicinity of the Almonda caves is quite diverse, which facilitated detecting movements even over just a few kilometers."

Co-author Professor Alistair Pike, who oversaw the research at the University of Southampton, stated, "This research demonstrates the extent to which science has revolutionized our perception of archaeology in the last decade. Before, our comprehension of the lives and customs of past individuals was restricted to what we could infer from marks on their bones or the artifacts they used. Now, by utilizing bone and teeth chemistry, we can commence rebuilding the life histories of individuals, even stretching back to the time of the Neanderthals."

Co-author Professor João Zilhão of the University of Lisbon, who directed the excavation of the Almonda caves, remarked, "The difference in the size of the territory between the Neanderthal and Magdalenian individuals is likely due to population density. Neanderthals had the freedom to roam further in search of large prey species like horses, without encountering rival groups, owing to relatively low population density. With the increase in population density by the Magdalenian period, available territory decreased, and human groups had to move down the food chain, occupying smaller territories and hunting mostly rabbits while catching fish on a seasonal basis.

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