Neanderthals were the closest extinct relatives of modern humans. They inhabited Europe and parts of western and central Asia for hundreds of thousands of years before disappearing as a distinct human population around 40,000 years ago. For a long time they were portrayed as primitive, brutish cave dwellers, but archaeology and genetics have dramatically changed that image.
Neanderthals were physically well adapted to the cold climate of Ice Age Eurasia. They had compact, powerful bodies, prominent brow ridges and broad chests. Males averaged around 160 cm in height and females about 150 cm. Their brains were roughly comparable in size to those of Homo sapiens, although their shape differed.
They were skilled hunters who pursued large animals and used stone and wooden tools and spears. They processed animal hides and probably wore clothing. Their diet was not exclusively based on meat either – archaeological evidence shows that they also consumed plant foods depending on location, season and availability.
Growing evidence suggests their behaviour was considerably more sophisticated than once believed. Neanderthals cared for injured or sick members of their communities, and some archaeological discoveries have been interpreted as evidence of burial practices and symbolic behaviour. Decorative objects and pigments have also been discovered, although some claims about Neanderthal art remain debated.
The most fascinating chapter begins when Homo sapiens expanded into Eurasia. The two human populations did not merely encounter one another – they interbred. Genetic research shows that around 2–3% of the ancestry of present-day people outside Africa derives from Neanderthals.
Research published in 2026 has added another intriguing detail. Genetic analysis indicates that interbreeding was strongly sex-biased: pairings between Neanderthal males and Homo sapiens females appear to have been more common than the reverse. The reason for this pattern remains unknown.
But if Neanderthals were intelligent, highly adapted to their environment and capable of having children with Homo sapiens, why did they disappear?
Science still has no single definitive answer. Their disappearance was probably caused by a combination of factors.
Neanderthals generally lived in relatively small populations. When Homo sapiens expanded across Europe, they encountered another human population that may have possessed broader social networks and eventually became much more numerous. Climate fluctuations and changes in available food could have added further pressure.
New genetic evidence published in 2026, however, complicates the picture. Researchers analysed 27 Neanderthals from ten archaeological sites in Belgium and France and found that some late Neanderthal populations in northwestern Europe were relatively well connected. The researchers also found no evidence that genetic load progressively accumulated over time, weakening the idea that gradual genetic deterioration alone drove Neanderthals to extinction.
Another part of the explanation may lie in interbreeding itself. Not every Neanderthal group necessarily disappeared through death or direct competition. Some may gradually have been absorbed into expanding Homo sapiens populations.
This is why the word “extinct” does not tell the entire story.
Around 40,000 years ago, Neanderthals ceased to exist as a distinct human population, but part of their genetic legacy survived. Billions of people today carry fragments of Neanderthal DNA.
These ancient genetic variants are not merely historical traces. Some have been linked to immune function, metabolism and other biological traits, although their effects are complex and cannot simply be classified as beneficial or harmful.
The story of the Neanderthals therefore ends in an unusual way. They disappeared as a separate population, but not entirely from human history.
When Homo sapiens and Neanderthals encountered one another in Eurasia, the result was not simply competition. There was coexistence, interbreeding and children.
Tens of thousands of years later, part of those Neanderthals is still written into our DNA.
