Were Neanderthals the same as modern humans, or were they an entirely different species? This is a major topic of debate among Anthropologists, and many people strongly argue each view, backing their opinion with evidence from physical remains and inferred ideas about behavior.
The proponents of the separate species hypothesis believe that they had a common ancestor, but Neanderthals and modern humans were separate species. They argue that the Neanderthal line was a dead end, and that for some reason Homo sapiens thrived while they went extinct.
Most of their evidence comes from the fossilized bones of Neanderthals and Cro- Magnons, or modern mans ancestors (Shreeve, 150). There is a definite difference between their bone structures, and it may be a significant enough difference to divide them into species. There is a set of traits that distinguishes Neanderthals. Their general proportions are short, robust, and strong. Males and females of all ages have thick bones, and very pronounced muscle and ligament attachment sites. They also have distinct facial and cranial features. They have a large skull with no chin, a significant brow-ridge, and a large nasal opening (Shreeve, 49-150). They have large brains, around 1400cc, that protrude in the back, causing an occipital bun in the skull (Lecture, 4/19). Cro-Magnons on the other hand look more like humans do today. They are more slender and not as muscular, with chins and rounder skulls with slightly smaller brains among other traits.
From the ancient bones of the Neanderthals, scientists have been able to extract small amounts of DNA. The DNA comparisons to modern humans show no relationship, implying evolutionary separation (Kunzig, 159). Some anthropologists say the small sections of DNA found are not conclusive evidence, because modern humans show just as much variation in DNA. These people point out that individuals such as the Portugal Kid are hybrids of Neanderthals and modern humans, showing there was gene trading. One argument against this is that there is no skull from the Portugal Kid so it is hard to compare it to Neanderthals. Also, it is known that closely related species can breed and their offspring can be fertile, but they are still separate species (Kunzig, 161).
Other evidence includes where the bones are found, and what artifacts they are found with. Neanderthals are believed to have lived all over Europe and the Middle East from around 130 thousand years ago until 30, 000 years ago. Cro-Magnons did not appear in Europe until about 40,000 years ago (Shreeve, 150). The Neanderthals seem to have been geographically separated from other humans for a long time, in a different environment. These factors gave the Neanderthals a chance to evolve separately, maybe enough to become a species (Shreeve, 156). Even when the two species met and coexisted for thousands of years, they continued to have very distinct morphological traits. If they were the same species, gene flow would have blurred the differences, but little evidence of this is found.
The archaeological evidence shows a difference in culture and behavior. Neanderthals did not come up with innovative technology that modern humans did, such as refined stone and bone tools (Jurmain et al., 349). Their method of hunting seems to have involved close contact with strong animals, which can be inferred from the numerous injuries seen in their skeletons (Trinkaus, 134). Humans learned how to hunt with long distance weapons, such as spears. Along with their inferior functional tools, the Neanderthals did not make many symbolic artifacts. Modern humans created bone and tooth necklaces, stone sculptures, and cave art. In Europe, none of this is found with the Neanderthals until the Cro-Magnons brought it with them in their migration.
Even after the Neanderthals started making art, it was not as elaborate (Jurmain et al, 149). An important difference is that Neanderthals tended to live in small family groups, while humans lived in communities. These cultural differences define the Neanderthals as a separate set of humans. Because the Homo sapiens had behavioral and cultural advantages that might have created reproductive advantages as well, they monopolized the resources and wiped out the species Homo neanderthalis.
On the other hand of the whole issue, some people think evidence exists that indicates Neanderthals were modern humans, they were just separated geographically from the rest of their species. The differences between the two groups merely show adaptations to different environments.
One reason the Neanderthals were thought to be so different from modern humans is the unrealistic stereotype they have acquired. They were thought to be unintelligent, ugly creatures that didnt walk straight and couldnt talk. Modern interpretations of the skeletons show that they walked like us, talked like us, and thought like us.
Their build is short and stocky because of the cold environment they lived in. This follows Bergman/Allan rules, which state body shape reflects climate (Lecture, 4/19). The Inuit are very short and stocky when compared to Africans, and this intra-species variation is just a climatic adaptation. Also, physical differences alone cannot distinguish individuals as being different species. There is so much variation within our species today, and even more dramatic variation can be seen in other species, such as dogs.
An important morphological similarity is the hyoid bone, the bone in the throat that supports the vocal chords. When one was found in a Neanderthal in Kebara, Israel, it was almost identical to a modern humans. This meaning they had the same ability for speech (Lecture, 4/19). This disproves the idea that the Neanderthals did not have language, and it is an important similarity that unifies the species.
The Neanderthals were just as capable of creating tools and art as modern humans. In Levant, the small fertile area between Africa and Eurasia, Neanderthals and humans appear to have coexisted after they both migrated from their homelands into the area. For at least 25,000 years, possibly a lot longer, the two groups lived side by side. The Cro-Magnons here did not have fancy tools, cave paintings, or jewelry, and neither did the Neanderthals. Their Stone tool technology seems to progress together, and behavioral patterns such as hunting and burial of the dead are congruent between the groups. Some anthropologists believe that if two human groups are living together, behaving the same way, then they should be considered the same species (Shreeve, 151).
They had complex culture and society, just like modern humans. They intentionally buried their dead, usually in specific positions, sometimes with other artifacts and flowers (Lecture, 4/19). They hunted the same animals, using the same methods in some cases. Even though in many areas, it appears that certain cultural facts appeared with the arrival of modern humans, it does not mean that the Neanderthals were less intelligent; they probably had the potential to do whatever the Cro-Magnons did, they just came up with a different way of doing things (Kunzig, 159). You cannot define a species because of cultural differences. The fact is that humans are constantly changing; you cannot say that because people in the U.S. do things drastically different than native Australian tribes that one is a different species.
The Portugal Kid appears to be excellent evidence supporting the same-species view. This 25, 000 year old child shows features of both Neanderthals and modern humans. To the advocates of this argument, this proves that Neanderthals were not replaced by humans; they simply blended in to the population with more modern traits (Kunzig, 157). In other areas where the two groups seem to have merged, for example Levant, the skeletons seem like a mix of the two to their excavators (Shreeve, 153). According to anthropologists such as Joao Zilhao of Portugal, who discovered the child, Cro-Magnons and Neanderthals had been interbreeding for thousands of years. The Portugal Kid has a relatively robust frame with limb proportions of a Neanderthal, but also has small front teeth and a chin, like a Cro-Magnon. The chin however recedes slightly behind the teeth, which is typically a Neanderthal trait. The age of the fossil is interesting also, because 25,000 years ago Neanderthals werent around anymore, so the boy is essentially a modern human with Neanderthal traits (Kunzig, 160).
My own opinion on this issue is that from the evidence at hand, there is no way to know for sure whether or not the Neanderthals were our species. From the skeletal evidence, it is clear that they were anatomically different from modern humans, and we know that this is because of geographic isolation. We also know that they have been found in the same locations, and it appears at the same time. If they were truly part of our species, then there would have been blending of the two types in these places. Trying to determine this from fossilized bones from a tiny percent of the population, limited DNA, and imperfect dating methods is impossible. Even if anthropologists think they are sure of either viewpoint, there may be evidence out there that will prove them wrong. So at this point in time, I think both scenarios are equally possible.