The Mysterious Downfall of the Neandertals

[Gawdzilla Sama]

The Mysterious Downfall of the Neandertals
Paleoanthropologists know more about Neandertals than any other extinct human. But their demise remains a mystery, one that gets curiouser and curiouser

Key Concepts

* Neandertals, our closest relatives, ruled Europe and western Asia for more than 200,000 years. But sometime after 28,000 years ago, they vanished.
* Scientists have long debated what led to their disappearance. The latest extinction theories focus on climate change and subtle differences in behavior and biology that might have given modern humans an advantage over the Neandertals.


Some 28,000 years ago in what is now the British territory of Gibraltar, a group of Neandertals eked out a living along the rocky Mediterranean coast. They were quite possibly the last of their kind. Elsewhere in Europe and western Asia, Neandertals had disappeared thousands of years earlier, after having ruled for more than 200,000 years. The Iberian Peninsula, with its comparatively mild climate and rich array of animals and plants, seems to have been the final stronghold. Soon, however, the Gibraltar population, too, would die out, leaving behind only a smattering of their stone tools and the charred remnants of their campfires.

Ever since the discovery of the first Neandertal fossil in 1856, scientists have debated the place of these bygone humans on the family tree and what became of them. For decades two competing theories have dominated the discourse. One holds that Neandertals were an archaic variant of our own species, Homo sapiens, that evolved into or was assimilated by the anatomically modern European population. The other posits that the Neandertals were a separate species, H. neanderthalensis, that modern humans swiftly extirpated on entering the archaic hominid's territory.

Over the past decade, however, two key findings have shifted the fulcrum of the debate away from the question of whether Neandertals and moderns made love or war. One is that analyses of Neandertal DNA have yet to yield the signs of interbreeding with modern humans that many researchers expected to see if the two groups mingled significantly. The other is that improvements in dating methods show that rather than disappearing immediately after the moderns invaded Europe, starting a little more than 40,000 years ago, the Neandertals survived for nearly 15,000 years after moderns moved in—hardly the rapid replacement adherents to the blitzkrieg theory envisioned.

These revelations have prompted a number of researchers to look more carefully at other ­factors that might have led to Neandertal extinction. What they are finding suggests that the answer involves a complicated interplay of stresses.

A World in Flux
One of the most informative new lines of evidence bearing on why the Neandertals died out is paleoclimate data. Scholars have known for some time that Neandertals experienced both glacial conditions and milder interglacial conditions during their long reign. In recent years, however, analyses of isotopes trapped in primeval ice, ocean sediments and pollen retrieved from such locales as Greenland, Venezuela and Italy have enabled investigators to reconstruct a far finer-grained picture of the climate shifts that occurred during a period known as oxygen isotope stage 3 (OIS-3). Spanning the time between roughly 65,000 and 25,000 years ago, OIS-3 began with moderate conditions and culminated with the ice sheets blanketing northern Europe.

Considering that Neandertals were the only hominids in Europe at the beginning of OIS-3 and moderns were the only ones there by the end of it, experts have wondered whether the plummeting temperatures might have caused the Neandertals to perish, perhaps because they could not find enough food or keep sufficiently warm. Yet arguing for that scenario has proved tricky for one essential reason: Neandertals had faced glacial conditions before and persevered.

In fact, numerous aspects of Neandertal biology and behavior indicate that they were well suited to the cold. Their barrel chests and stocky limbs would have conserved body heat, although they would have additionally needed clothing fashioned from animal pelts to stave off the chill. And their brawny build seems to have been adapted to their ambush-style hunting of large, relatively solitary mammals—such as woolly rhinoceroses—that roamed northern and central Europe during the cold snaps. (Other distinctive Neandertal features, such as the form of the prominent brow, may have been adaptively neutral traits that became established through genetic drift, rather than selection.)

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