Tooth enamel provides clues to Neanderthals’ hunter-gatherer lifestyle – ScienceDaily

Scientists examined the chemical properties found within tooth enamel to piece together how prehistoric people lived on the land surrounding the Almonda cave system, near Torres Novas in central Portugal, nearly 100,000 years ago.

Their findings, published in the journal PNAS, show that Neanderthals in the region hunted fairly large animals across vast swaths of land, while humans living in the same location tens of thousands of years later subsisted on smaller creatures in an area half as large. the size.

The isotopes of strontium in rocks change gradually over millions of years due to radioactive processes. This means that they vary from place to place depending on the age of the underlying geology. As the rock weathers, isotopic “fingerprints” are passed to plants via sediment, making their way along the food chain—and eventually transferring to tooth enamel.

In this study, archaeologists used a technique that samples enamel with a laser and takes thousands of individual measurements of strontium isotopes along the growth of a tooth’s crown. Samples were taken from two Neanderthals, dating from about 95,000 years ago, and from a more recent human who lived about 13,000 years ago, during the Magdalen period.

The scientists also looked at isotopes in the tooth enamel of animals found in the cave system. Besides strontium, they measured oxygen isotopes, which vary seasonally from summer to winter. This enabled them to determine not only where animals were located across the landscape, but in which seasons they were available for hunting.

The team showed that Neanderthals, who aimed for large animals, would have hunted wild goats in the summer, while horses, red deer and an extinct form of rhino were available year-round about 30 kilometers from the cave. The Magdalenian individual showed a different pattern of subsistence, with a seasonal movement of about 20 km from the Almonda Caves to the banks of the Tagus River, and a diet including rabbits, red deer, wild goats, and freshwater fish.

The researchers approximated the area of ​​the two different human groups, and revealed contradictory results. Neanderthals obtained their food at a distance of more than 600 km²while the Magdalenians occupied a much smaller territory of about 300 km².

Lead author, Dr Bethan Linscott, who conducted the research while at the University of Southampton and now works at the University of Oxford, said: “Tooth enamel forms gradually and thus represents a time series that records the geological origin of the food that an individual eats.

“Using laser ablation, we can measure the variability of strontium isotopes over the two or three years it takes for the enamel to form. By comparing the strontium isotopes in the teeth with sediments collected at various locations in the area, we were able to map the movements of Neanderthals and Magdalenians. The geology around the Almonda Caves is variable. This makes it possible to detect movement only a few kilometers away.”

Co-author Professor Alistair Pike of the University of Southampton, who led the research, said: “This study shows the extent to which science has changed our understanding of archeology in the past decade. Previously, the lives and behaviors of past individuals were limited to what we could infer from the marks on their bones or The artefacts they used. Now, using the chemistry of bones and teeth, we can begin to reconstruct individual life histories, even as old as Neanderthals.”

Co-author Professor Joao Zilhão of the University of Lisbon, who led the excavations of the Almonda Caves, said: “It is possible that the difference in area size between Neanderthals and Magdalenians was related to population density. With a relatively small population, Neanderthals were free to roam. to target large prey species, such as horses, without encountering competing populations.By the Magdalenian period, increases in population density had reduced available land, and human groups had moved down the food chain to occupy smaller areas, hunting mostly rabbits and fishing on a seasonal basis.”