Demographic disaster: the cause of Neanderthal extinction has been identified, along with the timeline of when it occurred.

Neanderthals inhabited Eurasia approximately 40,000 years ago, after which they disappeared as a species. Currently, scientists believe that the population of these hominids sharply declined around 70,000 years ago. As a result, the genetic and physical diversity within the Neanderthal population significantly decreased, leading to a largely uniform set of traits among the last representatives of this species, researchers say. The study was published in the journal Nature Communications, according to IFLScience.

Initially, scientists believe that a species known as proto-Neanderthals emerged, with their best-preserved skeletal remains dating back to about 430,000 years ago. At some point, the defining characteristics of this species began to coalesce, resulting in the appearance of early Neanderthals around 120,000 to 130,000 years ago. It is thought that classic Neanderthals appeared approximately 110,000 years ago, as they exhibited a range of distinctive morphological traits.

After scientists first sequenced the complete genome of classic Neanderthals 15 years ago, it became evident that this species was less genetically diverse than modern humans. This led to the hypothesis that these hominids experienced a demographic catastrophe or a bottleneck effect at some point, meaning a reduction in the gene pool or genetic diversity of their population.

The authors of the new study conducted an in-depth morphological analysis of the remains of various Neanderthal populations. By comparing samples of proto-Neanderthals with early Neanderthals and various classic Neanderthals, researchers were able to demonstrate how morphological diversity diminished throughout the existence of this enigmatic species.

The results indicated that early Neanderthals were more genetically variable than proto-Neanderthals. This suggests that genetic diversity must have increased during the period between 430,000 and 120,000 years ago. Thus, scientists rule out the possibility of a bottleneck effect occurring at the early stage of Neanderthal history.

However, classic Neanderthals exhibited a noticeable decrease in morphological variability compared to early Neanderthals. Consequently, researchers propose that the decline of the Neanderthal population began around 110,000 years ago. Over the next several tens of thousands of years, the genetic diversity of these extinct hominids decreased, likely leading to their extinction.