Over the past few years, several studies have illuminated some of what happened during the brief period when modern humans and Neanderthals overlapped in Europe, with genetic analyses showing that the two groups interbred tens of thousands of years ago (though not frequently) and ancient remains suggesting that modern humans fought and—more controversially—ate their prominent-browed contemporaries.
It seems that humans and Neanderthals made occasional love and intermittent war, but what were those interludes of interaction actually like? What was going on inside those distinctive crania? It’s a tricky question to answer—behavior doesn’t fossilize—but anthropologist Thomas Wynn and psychologist Frederick L. Coolidge combine genetic and anthropological evidence with a healthy dose of well-informed speculation to offer an intriguing picture of how Neanderthals may have lived, thought, felt, and acted.
Could Neanderthal DNA have protected our ancestors from diseases?
What’s the News: While we humans have certainly outlasted our hominin cousins, new research shows that Neanderthal and Denisovan genes may have helped us spread far and wide. By mating with the two species, our ancestors acquired genes that allowed them to adapt to diseases outside of Africa far quicker than would have been otherwise possible, according to Peter Parham, a professor of microbiology and immunology at Stanford University.
Neanderthals: They weren’t really into distance running. According to research by David Raichlen in the Journal of Human Evolution, they were more the power walking type: The shape of a Homo sapiens heel compared to that of a Neanderthal would have allowed our ancestors to be much more efficient runners over long distances.
Raichlen stated with living humans, studying them as they ran on treadmills.
By looking at MRI scans of their ankles, he found that the distance between a point on the heel bone just below the ankle bone, and the back of the heel bone where the Achilles tendon attaches, was proportional to the runner’s efficiency. The shorter this distance, the greater is the force applied to stretch the tendon – and the more energy is stored in it. This means that people with shorter distances are more efficient runners, using less energy to run for longer. [New Scientist]
With this knowledge, Raichlen and colleagues looked at the remains of Neanderthals as well as humans of the same era. The difference, he says, was distinct.
Diet, brains, murder at the hands of a certain species called Homo sapiens, life expectancy: These and more have been floated as reasons to explain the vexing question: Why did Neanderthals die out about 30,000 years ago while our ancestors persisted?
In a study in this week’s Proceedings of the National Academy of Sciences, Erik Trinkaus argues that we should scratch the last one—life expectancy—off the list. His wide-ranging survey of Neanderthal and early human remains shows that our ancestors had no particular advantage over the Neanderthals in living into old age.
Dr. Trinkaus studied fossil records of humans from across Eurasia and of Neanderthals from the western half of Eurasia to estimate adult mortality in the two groups. He found that there was approximately the same number of adults in the 20-to-40 age range and over-40 age range in both groups. [The New York Times]
Did Neanderthals enjoy some diversity in their diet? A study out in this week’s Proceedings of the National Academy of Sciences claims to offer more evidence that these hominids ate a wide-ranging diet including cooked grains and grasses rather than the cartoon caveman’s diet of meat, meat, and more meat.
Amanda Henry has made the case before; in April 2008 she said that micro-fossils of plant material could be found in the plaque of recovered Neanderthal teeth. Now, she says, her team has found more traces of grains and plants stuck in the teeth of Neanderthal fossils unearthed in Belgium and Iraq.
After analyzing a selection of these particles from European and Middle Eastern Neandertal dental remains, the team found “direct evidence for Neanderthal consumption of a variety of plant foods.” … Some of the Paleolithic snacks seem to have included legumes, date palms and grass seeds. The grasses were from the Triticeae group, which includes wild varieties of barley, rye and wheat relatives. [Scientific American]
Furthermore, the grains and starches present show the signature of having been cooked—probably by boiling in water—according to study author Dolores Piperno. To test this out the researchers themselves cooked similar grains, and the effects matched what they saw in the Neanderthal samples.
Neanderthals, it would appear, grew up in a big hurry. In a new study in the Proceedings of the National Academy of Sciences this week, Harvard anthropologists who studied Neanderthal teeth samples say that the evidence captured in those teeth show the rate at which they developed. Compared with human children, Neanderthal kids raced though their developing years and into adulthood, the researchers say.
Tanya Smith and colleagues used advanced X-ray scans of the tooth fossils of Neanderthals and the humans who lived concurrently with them to discover the layers therein. She says such scans reveal “growth lines” that serve the same purpose as tree rings–they allow researchers to measure the individual’s development year by year, and to determine his or her exact age at death.
Even when compared to some of the earliest human teeth, taken from remains of humans who left Africa 90,000 to 100,00 years ago, the differences were clear. Human teeth grew more slowly, pointing to more leisurely periods of youth. “This indicates that the elongation of childhood has been a relatively recent development,” the study said. [AFP]
When you were born, your brain was more elongated than it is now; it rounded out into its more globular shape as you grew up and crammed it full of knowledge. Neanderthals, it appears, were born with brains in that same elongated shape. But in their case it never changed: Adult Neanderthals’ brains didn’t move to the more rounded shape like ours, according to a study now out in Current Biology.
Scientists have long known that Neanderthals had brains that were about as big as our own, but this study may help explain how their cognitive abilities differed.
[The researchers used CT scans] to study nine fossil Neandertals, including a newborn, a year—old baby, and three children. Because the brain does not fossilize, they studied endocasts, imprints of the brain left in the skull. They found that at birth, both Neandertal and modern human infants had elongated braincases that were similar in shape, although Neandertal faces were already larger. But by age 1 or so, modern humans had grown globular brains, whereas Neandertal babies had not. [ScienceNOW]
Neanderthals, in keeping the same basic brain shape throughout life, maintain the pattern of brain development seen in chimpanzees. In contrast, modern humans have evolved a unique pattern, says lead researcher Philipp Gunz:
Over the past few years, studies have chipped away at the old-fashioned stereotype of dense and dumb Neanderthals. Archaeological excavations suggested the hominids made tools and weapons, fashioned jewelry, or possessed other mental faculties some presumed only early humans to have.
The Neanderthal renaissance may be in danger. For a study in the Proceedings of the National Academy of Sciences this week, radiocarbon dating expert Thomas Higham tested one of the most important Neanderthal sites in the world—Grotte du Renne in France—and found that all is not well in dating the artifacts that some archaeologists have connected to Neanderthals.
The key finding is that as you dig down through the layers of sediment in the Grotte du Renne, the age of the remains does not increase as you would expect. Instead, the ages of the different objects are all over the place, suggesting that remains from different eras have got mixed up together. [New Scientist]
Ever since anthropologists figured out that early humans and Neanderthals coexisted for a span of prehistory, they’ve wondered–did the two species, you know, make friends? Now a fascinating new genetics study reveals that Homo sapiens and Neanderthals did indeed interbreed, and the evidence is still to be found in the human genome.
Researchers from Germany’s Max Planck Institute for Evolutionary Anthropology first sequenced the entire Neanderthal genome from powdered bone fragments found in Europe and dating from 40,000 years ago–a marvelous accomplishment in itself. Then, they compared the Neanderthal genome to that of five modern humans, including Africans, Europeans, and Asians. The researchers found that between 1 percent and 4 percent of the DNA in modern Europeans and Asians was inherited from Neanderthals, which suggests that the interbreeding took place after the first groups of humans left Africa.
Anthropologists have long speculated that early humans may have mated with Neanderthals, but the latest study provides the strongest evidence so far, suggesting that such encounters took place around 60,000 years ago in the Fertile Crescent region of the Middle East [The Guardian].
The study, published in Science and made available to the public for free, opens up new areas for research. Geneticists will now probe the function of the Neanderthal genes that humans have hung on to, and can also look for human genes that may have given us a competitive edge over Neanderthals.
Erik Trinkaus, an anthropologist at Washington University in St. Louis, who has long argued that Neanderthals contributed to the human genome, welcomed the study, commenting that now researchers “can get on to other things than who was having sex with who in the Pleistocene” [AP].
The Loom: Skull Caps and Genomes
Gene Expression: Breaking: There’s a Little Bit of Neandertal in All of Us
80beats: We May Soon Be Able to Clone Neanderthals. But Should We?
80beats: Crafty & Clever Neanderthals Made Jewelry 50,000 Years Ago
80beats: Did Spear-Throwing Humans Kill Neanderthals?
80beats: Rough Draft of the Neanderthal Genome is Complete!
DISCOVER: Works in Progress asks whether we rubbed out Neanderthals, or rubbed off on them
Image: Max Planck Institute EVA. The researchers hang out with their Neanderthal relation.
Last year DISCOVER asked the question, “Did We Mate With Neanderthals, or Did We Murder Them?” Now, Zach Zorich at Archaeology magazine is asking another big question about our hominid siblings: Should we bring them back?
Thanks to a slew of recent advances, the possibility is getting closer. 80beats reported a year ago that researchers had published the rough draft of the Neanderthal genome. However, that’s likely to contain many errors because it’s so difficult to reconstruct ancient DNA. Within hours of death, cells begin to break down in a process called apoptosis. The dying cells release enzymes that chop up DNA into tiny pieces. In a human cell, this means that the entire three-billion-base-pair genome is reduced to fragments about 50 base-pairs long [Archaeology].
Even if scientists succeed in figuring out the entire Neanderthal genome, they’d be faced with another problem before they could even consider the possibility of cloning one of these ancient hominids: We don’t have any living Neanderthal cells to work with. Thus, researchers will have to figure out how to put DNA into chromosomes, and how to get those chromosomes into the nucleus of a cell. What about altering the DNA inside a living human cell, and tweaking our genetic code to match the Neanderthal’s? This kind of genetic engineering can already be done, but very few changes can be made at one time. To clone a Neanderthal, thousands or possibly millions of changes would have to be made to a human cell’s DNA [Archaeology].
Even if scientists manage to put Neanderthal DNA in a cell nucleus, their problems aren’t over. The next step in creating a baby clone is to move the cell nucleus into the egg of a related species in a technique called nuclear transfer, and then implanting the altered egg in a female who can bear it to term. But in this process, which has been extensively tested on animals, cells often get sick or die, causing fetuses to die in the womb or clones to die young. That’s why the vast majority of scientists oppose using this method on people. Even if nuclear transfer cloning could be perfected in humans or Neanderthals, it would likely require a horrifying period of trial and error [Archaeology].