Some Neanderthals used "aspirin" to cure their aches and pains
The secret to learning about our ancient human ancestors may lie in their teeth.
Neanderthals were a group of human-like creatures that lived some 40,000 years ago. According to the plaque on their teeth, Neanderthals had striking differences in their diets, depending on where they lived. They may have also used plants and mold to treat illness and pain.
The findings, described in the journal Nature, mark the first and oldest dental plaque to be genetically analyzed. They shed light on the relationship between humans and their closest extinct relatives. It also hints at the complexity and diversity of Neanderthal life across Europe.
Picking Out What They Ate
"The typical view of a Neanderthal is a club-toting beast who grunts at people and lives in a cave," said lead author Laura Weyrich, a scientist at the University of Adelaide in Australia. But this research, she says, "suggests that these were very capable and intelligent individuals." They could "pass down information from generation to generation and likely lived in friendly contact with humans at some point," she says.
When scientists look to understand a creature's diet, they can look to its teeth. Specifically, they look at layers of hardened dental plaque on the surface of the teeth. This muck contains the DNA of food particles, as well as the microbes that lived in the mouth.
Scientists have studied the information contained in tooth plaque for decades. Now, with recent technological breakthroughs, Weyrich and her colleagues were able to pick out what they ate and the microbes in their bodies.
Dinner With A Side Of Neanderthal
The international team of researchers looked at Neanderthal samples. The first was taken from Spy cave in Belgium and it is around 36,000 years old. The second is from El Sidron cave in Spain and is around 48,000 years old.)
The human ancestors ate very differently, depending on where they lived. The preserved plaque from Spy cave was full of meat such as woolly rhinoceros and wild sheep. That made sense for creatures roaming open grasslands. The diet in Spain, on the other hand, had plenty of mushrooms, pine nuts and moss, and no meat that they could find. That suggested they were forest-dwellers.
The Spanish Neanderthals, whether by necessity or by choice, may have been vegetarians. It's interesting that there were no squirrels or other small tree-dwelling animals in the plaque of the Neanderthals from Spain. Whether that was intentional or not remains to be seen, she said.
Incidentally, studies show the vegetarian Neanderthals apparently met a nasty fate.
Cut marks on their bones show they were probably eaten by other people.
"There are all sorts of wild stories, but the bottom line is we just don't know," she said. "We don't have a time machine to go back; we just have these little pieces we can try to assemble."
A Mouthful Of Medicine
One of the Neanderthals at the Spanish site had a stomach bacteria. It likely caused vomiting or diarrhea.
In his ancient plaque, scientists discovered evidence of the poplar tree, whose bark contains salicylic acid. That's the active ingredient in the painkiller aspirin. They also found signs of a mold called Penicillium rubens that works as a natural stomach reliever.
The scientists suspect that this individual did not specifically seek out that exact mold. He seemed to have consumed a wide range of molds. But it does suggest that they may have known that eating mold somehow made them feel better, the scientist added.
"When you had a stomachache, maybe you ate moldy grain as a way to try to treat bacterial infections," Weyrich said.
The scientists also managed to map the genome of the oldest microbe known to humans. By looking at the number of mutations in the genome, the scientists determined it was introduced to Neanderthals around 120,000 years ago. That puts it near the edge of the time period when humans and Neanderthals were mating with each other, Weyrich said.
There are a few ways to swap this microbe between species, she pointed out: by sharing food, through parental care or through kissing.
"We really think that this suggests that Neanderthals and humans may have had a much friendlier relationship than anyone imagined," Weyrich said.
"The Sky's The Limit"
Ultimately, she said, this study proved what scientists can learn from mapping the DNA preserved in ancient plaque.
"The sky's the limit for this," Weyrich said.
By using this technique on preserved specimens around the globe, scientists can start to understand how the human microbiome evolved over time, in response to changes in their diets and other factors. The microbiome is all the tiny organisms that live inside of humans.
More discoveries could inform researchers trying to understand microbiome-related diseases in modern humans. It could help change how doctors treat each of us as individuals, depending on what is in our microbiome.
"In modern humans, we have a really difficult time trying to understand how to change the microbiome or what lifestyle alterations might change these bacteria," Weyrich said. "But in ancient humans, they already did it for us. The experiment's already been run. We really just need to go back in time and look at it."