Neanderthals may have disappeared from Europe earlier than previously thought, according to new research.

Past studies have long suggested that European Neanderthals were wiped out between 41,000 and 39,000 years ago, but new data indicates that they disappeared from the Iberian Peninsula around 45,000 years ago, or some 5,000 years before the rest of Europe.

"Both conclusions are complementary and not contradictory," lead author Bertila Galván said in a statement.

The new timeline is based on the final occupations in the El Salt site in Spain, which is "a very robust archaeological context," Galván says. A team of researchers studied the extensive stratigraphic sequence at El Salt, and lithic objects found at the site such as the remains of goats, horses and deer, and six teeth from a young adult who may have belonged to one of the last groups of Neanderthals (Homo neanderthalensis) in the region.

According to the study, the Neanderthal population in the Iberian Peninsula gradually declined over several millennia as the climate grew colder and more arid.

Several theories have been put forth over the years as to what led to the demise of Neanderthals, including volcanic eruptions, inferior intelligence, and breeding into the modern human population. However, the reason why this ancient species was wiped out still remains a mystery.

Without further research, the exact placement of Neanderthals in our evolutionary history will continue to elude scientists. While evidence at El Salt and other sites in the Iberian Peninsula suggests that modern humans arrived in the region after the Neanderthals had disappeared, other studies have linked the migration of modern humans with Neanderthals, putting both species in the same place at the same time.

"These new dates indicate a possible disappearance of the regional Neanderthal populations around 45,000 years ago," the study's research team concluded.

Their findings were published in the Journal of Human Evolution.

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