An international team of researchers, led by the University of Southampton, conducted a study that sheds light on the hunting behaviors and diets of Neanderthals and other humans who lived in western Europe. Using tooth enamel, the scientists examined chemical properties to determine how prehistoric people survived off the land near the Almonda Cave system in central Portugal around 100,000 years ago.
The findings, published in the journal PNAS, reveal that Neanderthals in the area hunted larger animals over vast expanses of land, while humans who lived in the same location tens of thousands of years later subsisted on smaller creatures in an area only half the size.
The researchers utilized a technique that involved laser sampling enamel to obtain thousands of individual strontium isotope measurements along the growth of a tooth crown. Samples were collected from two Neanderthals dating back approximately 95,000 years and a more recent human who lived about 13,000 years ago during the Magdalenian period.
In addition, the scientists analyzed isotopes in the tooth enamel of animals discovered in the cave system. They measured oxygen isotopes, which vary seasonally from summer to winter, along with strontium. This enabled them to determine where the animals roamed across the landscape and during which seasons they were available for hunting.
According to the study, the Neanderthals hunted large animals like wild goats during the summer months. Other animals such as horses, red deer, and an extinct type of rhinoceros were available year-round within 30km of the cave. Meanwhile, the Magdalenian individual had a different subsistence pattern, moving seasonally about 20km from the Almonda caves to the banks of the Tagus River. Their diet included freshwater fish, rabbits, wild goats, and red deer.
The researchers estimated the territories of the two groups and found that the Neanderthals hunted over an area of around 600 km2, whereas the Magdalenian individuals inhabited a smaller territory of about 300 km2.
Dr. Bethan Linscott, the lead author of the study conducted while at the University of Southampton and currently working at the University of Oxford, explained that tooth enamel forms incrementally and records the geological origin of the food consumed by an individual over time.
The researchers used laser ablation to measure the variation of strontium isotopes over the two to three years it takes for enamel to form. By comparing the strontium isotopes in the teeth with sediments collected at different locations in the region, they were able to track the movements of the Neanderthals and the Magdalenian individual. The highly variable geology around the Almonda caves enabled them to detect even small movements of a few kilometers.
Professor Alistair Pike of the University of Southampton, who supervised the research, emphasized how much science has revolutionized archaeology in the past decade. With the chemistry of bones and teeth, researchers can reconstruct individual life histories, even going back as far as the Neanderthals.
According to Professor João Zilhão of the University of Lisbon, who led the excavation of the Almonda caves, the difference in territory size between the Neanderthal and Magdalenian individuals is probably due to population density. With a low population, Neanderthals had more freedom to hunt large prey like horses over larger territories without encountering rival groups. But as population density increased by the Magdalenian period, human groups had to move down the food chain and occupy smaller territories, hunting mainly rabbits and catching fish on a seasonal basis.
The study, titled “Reconstructing Middle and Upper Palaeolithic human mobility in Portuguese Estremadura through laser ablation strontium isotope analysis,” is published in the journal PNAS.
Source: University of Southampton