Historical story

Why we are the only humanoids

“Neanderthals probably did it several times successfully with our ancestors, but only modern humans have survived history.” On Wednesday evening, anthropologist and bestselling author Chris Stringer spoke about his research during the second Hoboken lecture at the Natural History Museum in Rotterdam.

Chris Stringer is a professor at the Natural History Museum in London and has been researching the origins of modern humans for thirty years. “In the past, this was mainly based on fossils, but today we have many more options. The genetic insights in particular have accelerated our field.”

Stringer starts his story 2.5 million years ago with Homo erectus . “This human species left Africa about 1.8 million years ago and spread to the Far East, to China and Java. He also ended up in Dmanisi, in Georgia. There, under the remains of a medieval village, scientists found fossils of a primitive predecessor of Homo erectus, the first representative of people who lived outside Africa.” So 1.8 million years ago, people could already be found outside Africa and close to Europe. “In that period, the climate did not fluctuate so much between warm and cold extremes. By the time people reached Europe, they had to deal with much greater extremes.”

It then took a few hundred thousand years before the first human beings took steps on European soil. “The oldest fossil found in Europe is a jaw from northern Spanish Atapuerca and it is 1.2 million years old. In the same area we have several fossils of another human species – Homo antecessor - found it. These bones are estimated to be 800,000 years old.”

Elephants in England

In order to survive in Northern Europe, some adjustments were then necessary. “In Northern Europe, the climate was much colder and more difficult to survive in than in the south. Fire was needed, shelters, better hunting techniques, and so on.” Research in England is very useful in determining when humans arrived in Northern Europe.

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“England is located in the Atlantic Ocean and therefore experiences the extremes of climate changes. If the Atlantic is freezing, so is England. For example, 120,000 years ago elephants and hyenas roamed England and 20,000 years ago it looked more like the tundra of northern Scandinavia with reindeer and foxes.” When was the climate favorable to arrive in England? "In Pakefield we found human remains from 700,000 years ago. At that time England was still attached to Europe by a land bridge and the crossing could be made. The climate was Mediterranean and therefore very favorable."

Dive for bones

In the English coastal town of Happisburgh, research has been carried out for years, also by Dutch scientists. “Tools found there indicate that humans were already there 900,000 years ago; but which species it was remains a mystery, as no fossils have been found so far. If it is true that people were already there then, we need to adjust our previous thoughts on climate adaptation.” 900,000 years ago, the climate in England was comparable to that in southern Sweden today. Divers are currently searching for clues off the coast.

Last common ancestor

600,000 years ago, another human species, Homo heidelbergensis , Europe. “I think that's a very interesting species in human evolution, because I think it's the last common ancestor of Homo neanderthalensis and Homo sapiens used to be." The species was widespread. Stringer shows the audience pictures of skulls from Africa, France and Greece. "Evolutionarily, the species took two routes, evolving north of the Mediterranean in the Neanderthals and south of it in us, the Homo sapiens.

Discussion with the Spaniards

"And then we haven't looked at the people in England yet." 450,000 years ago, an ice age broke out. “We don't know whether people lived in England at the time. In any case, we have not found any indications of this, but it may be that the numbers were such small that we cannot find any traces of them."

50,000 years later, in Swanscombe, England, life reappeared. “Animal fossils have been found there, as well as a human fossil. That is an interesting specimen because it differs from the Homo heidelbergensis. Some characteristics resemble those of the Neanderthal. This man could be at the origin of the Neanderthal.”

Elsewhere in Europe there is also evidence for the splitting of Homo heidelbergensis in Homo neanderthalensis and Homo sapiens found it. “Deep in the cave system of Atapuerca, Spanish archaeologists found 6,000 human fossils, from about 28 individuals. Some of them are very similar to Neanderthals.” There was still a lot of discussion about these fossils. The Spanish colleagues claimed that the fossils are 600,000 years old. Stringer didn't trust that, after all, it contained teeth that were comparable to fossils of 400,000 years old. That's the right age, he says. “Meanwhile, the Spaniards themselves have also changed their assessment. A correction will be published shortly.”

Then Stringer takes a leap in history. Due to some major floods, England was deserted for a while, despite the warm climate. "But at least 60,000 years ago there were Neanderthals in England. At that time there was also plenty of land connecting us to the rest of Europe. Neanderthals were widespread at the time, as far as Siberia. They walked upright, had a similar (just slightly larger) brain volume than we do, but there were also clear differences. The big nose is such a characteristic difference.”

Out of Africa

Back to Africa. There, 200,000-year-old fossils have been found that clearly belong to modern humans, Homo sapiens to be. Stringer is therefore one of the people behind the out-of-Africa theory that modern humans originated in Africa and spread to Europe and Asia via the Middle East. “60,000 years ago, Homo sapiens from southern areas to the Neanderthal area. Genetic research indicates that Neanderthals and modern humans have interacted successfully on several occasions in different places. That stirs up the discussion whether it really was a different species.” Formally, different species cannot produce fertile offspring from each other.

Gaps in evolution

But Europeans all carry some Neanderthal DNA in our genome, and humans in China even more. "The Middle East seems like a logical place where the species met, unfortunately there is only DNA evidence and we are missing archaeological finds." How the Neanderthals eventually died out and whether modern humans are to blame, Stringer cannot say for sure. “We know from DNA studies that Neanderthals were already on the decline when they met modern humans. The genetic variation in the Neanderthal genome was already small at that time, indicating small populations.” What the final blow to Neanderthals was, therefore, remains unknown for a while. “There is still a lot to discover about human evolution.”

Read more about the evolution of man

Wil Roebroeks on the Neanderthal:an episode of Magic of Science.