Current evidence suggests that Neanderthals and humans shared a last common ancestor sometime between 765,000 and 550,000 years ago. We speculate that
Current evidence suggests that Neanderthals and humans shared a last common ancestor sometime between 765,000 and 550,000 years ago. We speculate that this ancestor was H. heidelbergensis . The story gets a little bit more complicated as there are also Eastern Neanderthals, called Denisovans, whose genetics seem to indicate a close affinity to European Neanderthals. Evidence for H. denisovans has been found in Siberia, Asia, and Melanesia. One major difference between early African humans and Neanderthals was their diet. This is because the cold, sparse winters in Eurasia would have restricted plant availability, forcing Neanderthals to rely more heavily on meat—indeed, chemical analysis of their bones shows that it dominated their diet.
It seems Neanderthals were specialized seasonal hunters, and there is evidence for them killing reindeer in winter and red deer in summer. Neanderthal archaeological sites contain sharp wooden spears and large numbers of bones of big game animals, showing evidence of hunting and butchery. Neanderthals were, however, adaptable, and at the Gibraltar coastal site there is evidence they exploited marine resources such as fish, molluscs, seals, and even dolphins. They did also eat plants, and remains of starch grains have been found in excavated Neanderthal molar teeth.
Neanderthals did eat plants as evidence from the study of Neanderthal teeth. (Thilo Parg / CC BY-SA 4.0 )
Neanderthals Had Sophisticated Stone Tools
Neanderthals also had a sophisticated stone tool industry . This differs from earlier ‘core tool’ traditions, such as the Acheulean tradition of H. erectus . Acheulean tools are created by removing flakes from the surface to ‘reveal’ a tool. In contrast, the Neanderthal Mousterian stone tool industry is characterized by flake tools that were detached from a prepared stone core. This innovative technique allowed multiple tools to be fashioned from a single suitable stone. Neanderthals used tools for activities such as hunting and sewing. There is evidence for left–right arm asymmetry, which was originally assumed to have developed from the hunting technique of thrusting spears instead of throwing them. This is in contrast to other hominins, such as Homo erectus , H. heidelbergensis , and H. sapiens , that had shoulder adaptations to allow them to throw weapons, and in the case of the later two species there is archaeological evidence for thrown spears.
he Neanderthals’ style of hunting at close quarters has been used to explain why Neanderthal bones have such a high frequency of fractures, as these injuries are similar to those among professional rodeo riders who regularly interact with large, dangerous animals. Colin Shaw from Cambridge University, however, has suggested a less glamorous reason for asymmetry between the arms. He suggests that Neanderthals may have spent hours scraping animal hides for clothing production, using stone tools. This would have been an arduous and repetitive task, but essential in the cold conditions in which they lived. The asymmetry in the arms of Neanderthals has no direct analogy in modern humans but some sports people, such as cricketers and tennis players, do have very pronounced one-sided development.
Neanderthals had a sophisticated stone tool industry. ( Andy Ilmberger / Adobe)
Neanderthals Practiced Sophisticated and Symbolic Behavior
One of the reasons Neanderthals are so interesting to palaeoanthropologists is because they are the first species to show evidence of wearing clothes and of consistent symbolic behavior . Scrapers and stone and bone awls have been found, along with animal bones, at Neanderthal sites. It is suggested the Neanderthals would have used a scraper to first clean the animal hide, then an awl to poke holes in it, and strips of animal tissue to lace together a loose-fitting garment. It is only with modern humans that we find evidence of the bone sewing needles needed to make tighter fitting clothing. Neanderthals also controlled fire and lived in shelters . There is evidence that Neanderthals deliberately buried their dead and occasionally even marked their graves with offerings, such as flowers. This may also explain why we have such a rich history of Neanderthals, as the burials greatly enhance the chances of preservation. They also made symbolic and ornamental objects such as grooved and perforated animal teeth, mammoth ivory rings, decorated bone tools, and used colorants. No other species had ever practiced this sophisticated and symbolic behavior.
Neanderthals wore clothes, controlled fire, and lived in shelters. (Victuallers / CC BY-SA 3.0 )
Neanderthals Interacted With Other Hominin Species
Neanderthals and modern Homo sapiens may have inhabited similar geographic areas in Eurasia for nearly 50,000 years. They may have had little direct interaction for most of this time as recent genetic evidence suggests that the Neanderthal population was very small compared with H. sapiens over the 400,000 years of their existence. There is, however, clear genetic evidence that the two species did interact at some stage. Scientists have recently sequenced Neanderthal mitochondrial and nuclear genomes. When compared with modern humans, it seems that many non-African people have between 2 and 4 per cent Neanderthal ancestry, meaning that Neanderthals and early humans must have interbred. It is also clear that Europeans and Asians have inherited Neanderthal genetic material, while some Asians have also inherited Denisovan genetic material. This admixture, though small, may have provided adaptive advantages to non-African humans. Just a few thousand years after modern humans moved into Europe, Neanderthal numbers dwindled to the point of extinction. All traces of Neanderthals disappeared about 40,000 years ago. There is an endless debate as to whether H. sapiens simply outcompeted Neanderthals , or whether there was proactive culling, or both.
Neanderthals interbred with other hominin species. (Jaroslav A. Polák / CC BY-SA 2.0 )
By 40,000 years ago we think that H. sapiens was the last hominin species having outcompeted, interbred, and even killed off the other hominin species. We humans are the only ultrasocial creature on the planet. We co-habit in cities of tens of millions of people and violence between individuals is extremely rare—even though this is not the picture painted by the media. So, when we study human evolution we need to understand the cause of the development of our extremely large, flexible and complex ‘social brain’. Of course, we can see many advantages in having a large brain. First, it allows humans to exist in a group size of about 150, which builds resilience to environmental changes, by increasing and diversifying food production and sharing. Humans have no natural weapons but living in large groups and having tools allowed humans to become the apex predator, hunting animals as large as mammoths . Larger groups also offer more protection from other predators. Second, it allows specialization of skills such as support for childbirth, tool-making, and hunting.
Comparison of faces of Homo sapiens and Neanderthal. (The Nature Box / CC BY-SA 4.0 )
There is new genetic evidence by Aida Gomez-Robles and colleagues at The George Washington University that suggests the modern human brain is indeed extremely flexible. They showed that the human brain is more plastic and is modeled more by the surrounding environment than that of chimpanzees. The anatomy of the chimpanzee brain is strongly controlled by their genes, whereas the human brain is extensively shaped by the environment, no matter what the genetics. This means the human brain is pre-programmed to be extremely flexible; its cerebral organization is adjusted by the environment into which it has been born and raised. So, each new generation’s brain structure could adapt to new environmental challenges without the need to evolve physically. This may also explain why we all complain that we do not understand the next generation, as they have different brain structures from us because they have grown up within a different physical and social environment.
Having a large brain does not mean that culture and society were inevitable—far from it, as there seem to be other requirements before human culture could start to build up. These may have involved a reduction in reactive violence, and populations of humans simply reaching a size at which inventions and new ideas were not lost, and real accumulation of knowledge could occur.
But once humans had a cumulative culture, then things started to change—first with the agricultural revolution and later with the industrial revolution.
Top image: Neanderthal. Source: procy_ab / Adobe Stock
© [Oxford University Press]
Extract from The Cradle of Humanity by Mark Maslin, published by Oxford University Press on 24 th January 2019, available in hardback, paperback, and eBook formats
By Mark Maslin