It’s long been an insult to be called a Neanderthal. But the more these elusive, vanished people have been studied, the more respect they’ve gained among scientists.
Recently, a team of researchers offered compelling evidence that Neanderthals bore one of the chief hallmarks of mental sophistication: they could paint cave art. That talent suggest that Neanderthals could think in symbols and may have achieved other milestones not preserved in the fossil record.
“When you have symbols, then you have language,” said Joao Zilhao, an archaeologist at the University of Barcelona and co-author of the new study.
When Neanderthal fossils first came to light in the mid-1800s, researchers were struck by the low, thick brow ridge on their skulls. Later discoveries showed Neanderthals to have brains as big as our own, but bodies that were shorter and stockier.
By the early 1900s, scientists were describing Neanderthals as gorilla-like beasts, an extinct branch of humanity that could not compete with slender, brilliant humans.
Yet evidence from both fossils and DNA indicates that Neanderthals and living humans descend from a common ancestor who lived about 600,000 years ago. Our own branch probably lived mostly in Africa.
For a few hundred thousand years after split, the ancestors of living humans left behind such basic tools as stone axes for butchering carcasses and spear blades for hunting.
But about 70,000 years ago, humans in Africa began showing signs of more abstract thinking. They colored and pierced seashells, for example, possibly to wear as jewelry.
Modern humans began expanding from Africa, arriving in Europe roughly 45,000 years ago. By then, they had become capable of even more impressive symbolic creations, including ivory carvings and extravagant paintings on cave walls.
Neanderthals disappeared abruptly afterward, about 40,000 years ago, leaving behind a fossil record of their own from Spain to Siberia.
Stockier than their African cousins, they appear to have evolved physical adaptations to harsh climates. They made stone tools of their own, which they used to hunt for game, including rhinos and other big mammals.
At first, researchers found no clear evidence of symbolic thought in Neanderthals. But in recent years, that picture has begun to change.
Neanderthals could use feathers and bird claws as ornaments, archaeologists found. But some scientists were skeptical about what these findings meant.
Neanderthals might have lived near modern humans, after all, and spotted them making things. Neanderthals were smart enough to copy the ornaments, the thinking went ? but not enough to invent them.
This debate was fueled in part by technological uncertainty: It can be very difficult to pin down a firm date for fossils and artifacts.
To determine the age of cave paintings, for example, researchers have traditionally relied on radiocarbon dating. But that method works only if the paint contains carbon-bearing ingredients, such as charcoal. Red ocher, by contrast, can’t be dated this way.
Making matter worse, radiocarbon dating becomes increasingly unreliable beyond about 40,000 years.
Dr. Zilhao joined with archaeologists Alistair G.W. Pike of the University of Southampton and Dirk L. Hoffmann, now at the Max Planck Institute for Evolutionary Anthropology in Germany, to see if the prehistory of European art could be brought into sharper focus.
Instead of studying radiocarbon, they would use a different clock to tell time.
As water seeps into caves, it may deposit milky crusts of minerals on the walls known as flowstones. Flowstones contain tiny amounts of uranium, which slowly breaks down into thorium. The older a flowstone gets, the more thorium builds up inside it.
A flowstone covering a piece of cave are might give Dr. Zilhao and his colleagues a minimum age for its creation. The problem was that scientists usually needed big chunks to find enough uranium and thorium to measure. The flowstones on cave art were typically very small.
But Dr. Hoffman had been working on ways to drastically increase the sensitivity of the technology so that he could work with much smaller samples.
The researchers returned to caves in Spain where ancient paintings had been discovered over the past century. The artists had drawn abstract images on the cave walls, including long lines, patterns of dots, and the outline of a human hand.
