Neanderthals and Homo sapiens: What Really Happened?
Neanderthals were the predecessors of modern Homo sapiens that inhabited Europe and parts of west and central Asia until about 30,000 years ago. An increasing number of researchers believe that the Neanderthals were driven to extinction following the arrival of modern Homo sapiens, but others maintain that the two species interbred and managed to survive in this fashion. To determine the facts in this case, this paper provides a review of the controversy concerning whether Homo sapiens and Neanderthals interbred or Neanderthals were driven to extinction by the arrival of anatomically modern Homo sapiens. A summary of the research and salient findings are presented in the conclusion.
Review and Discussion
They were a lot like us in many ways, and were well suited to their environment for thousands of years; however, Neanderthals became extinct about 30,000 years or so ago (this date continues to change based on new archaeological evidence as discussed further below) and many scientists believe it was because of the competition for resources from modern Homo sapiens that caused their demise. Some researchers believe that Neanderthals are simply a variant of Homo sapiens use the designation Homo sapiens neanderthalensis (Tattersail 7). The species got its name from the location of the cave where their remains were first discovered. For instance, in his book, Maps of Time: An Introduction to Big History, Christian (2004) reports that, “The first Neanderthal fossils were found in 1856 in the Neander valley in Germany. Though Neanderthals were long assigned to the same species as modern humans (technically, they were known as Homo sapiens neanderthalensis), recent genetic tests, using remnant DNA from Neanderthal fossils, suggest that the human and Neanderthal lines diverged perhaps as much as 700,000 to 550,000 years ago” (167).
The manner in which the Neanderthals prospered and then died out has been the focus of an increasing amount of research in recent years, and with good reason. According to Tattersail (1999), “Perhaps no extinct species in the entire human fossil record is as germane to the understanding of those origins as is Homo neanderthalensis. There is certainly no better way in which we Homo sapiens can judge our own uniqueness in the living world than by measuring ourselves against the Neanderthals and their achievements” (7). The popular conception of Neanderthals by many people today is one of brutish-looking, fur-clad cavemen wielding clubs and dragging their women by the hair into caves for fun and games, yet the conceptions are misguided. According to Tattersail, “Many scientists now prefer to minimize the differences between us and the Neanderthals, and clearly the dismal public image of Neanderthals demands rehabilitation” (7).
About 30,000 years ago, Neanderthals had disappeared from the fossil record following a period of more than 150,000 years of life in an enormous geographic region that spanned from the Atlantic to Uzbekistan. Given their relative successes at surviving during this harsh period in history, scientists remain puzzled concerning what happened to them. In this regard, Tattersail reports that the Neanderthals.”.. had led hard lives, certainly: virtually none of the Neanderthal fossils known is that of an individual who survived beyond the age of about forty years, and few made it past thirty-five. Degenerative joint disease was common among these people, and many Neanderthal bones show evidence of injury” (198). The Neanderthals, though, had managed to successfully occupy a large region of the globe for a lengthy period of time during which climates fluctuated sharply; it is reasonable to assume, then, that their way of life was sufficiently diverse to allow appropriate responses to these drastically changing environmental conditions. Given this ability to adapt to a wide range of challenging conditions, Tattersail suggests that there can only be one logical explanation for the extinction of the Neandethals: “Their abrupt demise must thus have been due to an entirely new factor. And that factor, almost certainly, was us” (emphasis added) (198).
This observation is echoed by Hoffecker (2005) who reports that Homo sapiens were better equipped cognitively to adapt than their Neanderthal counterparts and because resources are by definition scarce, the outcome was predictable: “With fully developed cognitive abilities, sophisticated linguistic skills, and an ability to plan ahead, to conceptualize their world, Homo sapiens soon mastered the north” (ix). Notwithstanding these attributes and the Neanderthals’ demonstrated ability to adapt to harsh climatic changes, Homo sapiens were still superior in terms of the technological innovations that gave them a competitive edge: “Highly mobile, armed with a very sophisticated technology that included the eyed needle and the layered, tailored clothing made possible by it, our Ice Age ancestors had colonized much of Eurasia by 25,000 years ago, before the last cold snap of the Weichsel glaciation that climaxed 18,000 years ago” (Hoffecker ix).
According to Bisson (2004), Neanderthals are presented as having cognitive abilities similar to anatomically modern Homo sapiens; however, the products of their minds differed. For instance, this author notes that, “Anatomically modern Homo sapiens used symbols to both communicate and solidify group identity. Neanderthals did not” (Bisson 711). There were other significant similarities between Homo sapiens and Neanderthals as well. For example, Christian (2004) reports that Neanderthals’ brains were as large as, and perhaps even larger than, those of modern humans; however, their bodies were also more rugged and stockier. This author adds that, “They clearly had the ability to hunt, and this enabled them to occupy Ice Age landscapes that had not been inhabited by any earlier hominines — for example, in parts of modern Ukraine and southern Russia. However, their hunting methods were inefficient and unsystematic in comparison with those of modern foragers, or even humans of the upper Paleolithic era” (Christian 168).
Some useful insights into the anatomical similarities between Homo sapiens and Neanderthals can be gained through the recent articulation of the first Neanderthal skeleton on te left compared with an anatomically modern Homo sapien on the right as shown in Figure 1 below. Gary Sawyer of the American Museum of Natural History in New York city and Blaine Maley at Washington University in St. Louis, Missouri assembled the skeleton by taking casts of the La Ferrassie I specimen found in 1909 in the Dordogne valley in France, which is the most complete Neanderthal skeleton available; these scientists then filled in the blanks by taking casts from other Neanderthal collections from the same period (approximately 60-000 years ago). According to Sawyer, “It’s the first time any human ‘ancestor’ has ever been fully reconstructed” (quoted in Graham-Rowe at 3).
Figure 1. First complete reconstruction of a Neanderthal.
Source: Graham-Rowe, Mousterian (Neanderthal) Sites (2007): http://donsmaps.com/mousterian.html.
Moreover, as Knight, Studdert-Kennedy and Hurford (2000) point out, a larger brain does not necessarily translate into increased intelligence, or at least intellect that might contribute to the likelihood that the Neanderthals could overcome the challenges represented by the emergence of Homo sapiens and the competition for resources that ensued. These authors note that, “There is a marked discrepancy between brain expansion and human mental powers which is amply revealed in the fossil record. When the brain doubled in size, hominids didn’t get twice as smart” (Knight et al. 271).
The archaeological evidence found to date suggest that while their brains may have been as large or larger than Homo sapiens, Neanderthals were “stuck” in an evolutionary niche that they were unable to overcome: “Artefactual production and behavioral changes from Homo habilis to Neanderthals are insignificant compared to those found once our own species emerged, and unless there is no relationship whatsoever between intelligence and the products of intelligence (including tools and behavior), an enlarged brain did not, in and of itself, significantly enhance the former” (Knight et al. 271). These authors provide several possibilities concerning why Neanderthals failed to adapt or were otherwise driven to extinction, because it would appear that they had managed to survive alongside Homo sapiens for thousands of years, so there must have been an ultimate catalyst of some sort to account for their demise beyond competition with Homo sapiens as well. According to Knight and his colleagues (2000), “If brains of a critical size are crucial elements in the crossing of this threshold, then Neanderthals, with brains as large or larger than those of modern humans, should have had similar capacities to those of modern humans and, as the more adapted of the two (sub?) species to conditions in Ice-Age Europe, should not in so short a time have been driven to extinction” (280).
Some of the reasons these authors provide to explain the demise of the Neanderthals include:
Although Neanderthals may have been at least our equals in brain size, it is not clear that they were our equals in encephalisation. It seems likely that their stockier, less gracile bodies required a larger proportion of their brains for housekeeping tasks, leaving a correspondingly smaller area for the type of development envisaged here.
In certain areas such as the Near East, Neanderthals and modern humans coexisted for tens of thousands of years without any decisive advantage for one over the other, and indeed without significant differences in the quality, range or originality of their artifacts.
There is no reason to suppose that a difference as radical as true language vs. protolanguage is required to explain why modern humans replaced Neanderthals so quickly. In much shorter spaces of time, groups of modern humans have replaced other groups with identical biological capacities; it took only decades, not millennia, for Europeans to replace Tasmanians, for instance. The precise nature of Neanderthal capacities and of human-Neanderthal interactions remains tantalizingly obscure, and is still controversial (Knight et al. 281).
While the precise nature of the Neanderthal intellect and human-Neanderthal interactions remain unclear, there is some evidence in the archaeological record that lends support to the theory that Neanderthals simply did not have what it took to keep up with Homo sapiens. For instance, Findlayson reports that the stone tools used by the Neanderthals (usually described as being Mousterian), are more complex than those of Homo erectus; however, they also show far less variety and precision than the stone tools used by anatomically modern Homo sapiens (Christian 168). According to this author, “There are hints of Neanderthal art or burial ritual, both of which might have signaled an increased use of symbolic communication (but the evidence is ambiguous). And there is little sign of great social complexity. Like earlier hominines, Neanderthals seem to have lived primarily in simple family groups that had limited contact with each other. There is no evidence that Neanderthals could have had the same impact on the planet as modern humans” (Christian 168).
While it is perhaps reasonable to assert that the Neanderthals could have evolved to become as technologically proficient as their Homo sapien counterparts had they been given sufficient time, nature does not wait for any species and it would appear that the Neanderthals just could not compete. In this regard, Bisson reports that, “The Neanderthals survived alongside anatomically modern Homo sapiens for thousands of years because of their physical strength and cold-adapted bodies, but anatomically modern Homo sapiens ultimately triumphed because they continued to innovate their technology and because a cooling climate reduced the Neanderthals’ favored habitat while at the same time favoring the broader cultural alliances achieved by the larger and more integrated anatomically modern Homo sapiens’ societies” (711).
New discoveries in the archaeological record, though, continue to redefine the historic timeline during which Neanderthals flourished. In a recent report from Professor Clive Finlayson, of the Gibraltar Museum indicates that lived in southern Europe as recently as 28,000 years ago, had a varied diet and used sophisticated tools and weapons. The report notes that Homo neanderthalensis is widely believed to have survived in Europe until the arrival of anatomically modern Homo sapiens approximately 30,000 years ago; however, recent findings by Finlayson indicate that the two groups may have coexisted in Europe for 4,000 years or longer. According to Finlayson, “We are showing quite clearly that they survived at the very least until 28,000 years ago and possibly as recently as 24,000 years. That is significantly later than previously thought” (quoted in Camp find extends Neanderthal timeline 3).
The study also reports that during the period in which Europe was seized by an ice age, the last remaining Neanderthals had sequestered themselves in a temperate zone on the southern tip of Europe until their species became extinct. Not only is the archaeological record continuing to be redefined, these recent findings are also changing the way modern researchers view the Neanderthals. “Despite their image as club-carrying, hairy brutes,” Finlayson notes, “research suggests they were expert tool makers, used animal skins to keep warm and may have cared for each other” (Camp find extends Neanderthal timeline 4). The recent excavations at Gibraltar’s Gorham’s Cave have found a campfire made by Neanderthals and the remains of tools, flint weapons and animal fossils (Camp find extends Neanderthal timeline 4).
The remains found included mammals, birds and shellfish, and the charcoal found in the campfire at the site allowed researchers to carbon date it with accuracy. In addition, researchers were able to reconstruct the environment in which the late Neanderthals lived and determined that it included a wide range of plant materials. These findings suggest that the Neanderthals were able to live in some northern regions that were previously deemed inhospitable for them. In this regard, Finlayson reports that the findings indicate that.”.. In spite of the glaciations further up in Europe, this was a place where the climate was still sufficiently mild for populations of Neanderthals to survive quite late. The last Neanderthals that occupied Gorham’s Cave had access to a diverse community of plants and vertebrates on the sandy plains, open woodland and shrubland, wetlands, cliff and coastal environments surrounding the site. Such ecological diversity might have facilitated their long survival” (quoted in Camp find extends Neanderthal timeline 5). Researchers continue excavation in the Gibraltar cave where stone tools were discovered five decades ago; in addition, they will also be searching for Neanderthal burial sites in the cave’s less accessible areas (Camp find extends Neanderthal timeline 4).
In an effort to determine whether Neanderthals interbred with Homo sapiens at some point in the shared history, P bo and Krings investigated the sequence of Neanderthal DNA with the sequence from the equivalent section of modern human DNA. The findings of this study were clear: “Neanderthal DNA and human DNA were quite different. To be exact, P bo and Krings found the Neanderthal DNA varied from human DNA sequences by an average of 26 individual differences. To be sure the results were correct, researchers Anne Stone and Mark Stoneking repeated each step of the procedure at an independent laboratory at the Department of Anthropology of Pennsylvania State University. The DNA they extracted was exactly the same, which confirmed P. bo and Krings’ results” (cited in Meyer at 31). In a subsequent study, Krings, P bo and their colleagues extracted DNA from Neanderthal bones found in a cave in Croatia; the results of this study were consistent with the previous one and the DNA was shown to be quite different from that of modern humans (cited in Meyer at 33). According to Meyer, “There was only one conclusion that P. bo and his team could make. If Neanderthals truly were human ancestors, their DNA would have been much more similar to modern human DNA. Instead, their work provided the first truly clear evidence that Neanderthals could not possibly have been human ancestors” (32).
The research showed that the Neanderthals were a species genetically similar to anatomically modern Homo sapiens with brains as large or larger. Neanderthals were also shown to be rugged survivors with a penchant for opportunism, but the research was consistent in emphasizing that they just could not compete with the superior technologies and social arrangements brought to bear by Homo sapiens. Finally, the DNA studies to date suggest that Neanderthals did not interbreed with Homo sapiens, but they may have lingered longer in the caves at Gibraltar than scientists have previously believed.
Bisson, M.S. (2004). “The Neanderthal’s Necklace: In Search of the First Thinkers.” Journal of the Royal Anthropological Institute 10(3):710-11.
Camp find extends Neanderthal timeline.” (2006). ABC News Online: Reuters. [Online]. Available: http://www.abc.net.au/news/newsitems/200609/s1740994.htm
Christian, David. Maps of Time: An Introduction to Big History. Berkeley, CA: University of California Press, 2004.
Graham-Rowe, Duncan. (2005). “The first complete reconstruction of a Neanderthal.” Mousterian (Neanderthal) Sites. Online]. Available: http://donsmaps.com/mousterian.html.
Hoffecker, John F. A Prehistory of the North: Human Settlement of the Higher Latitudes. New Brunswick, NJ: Rutgers University Press, 2005.
Knight, Chris, Michael Studdert-Kennedy and James R. Hurford. The Evolutionary Emergence of Language: Social Function and the Origins of Linguistic Form. Cambridge, England: Cambridge University Press, 2000.
Meyer, Anna. Hunting the Double Helix: How DNA Is Solving Puzzles of the Past. Crows Nest, NSW: Allen & Unwin, 2005.
Tattersall, Ian. The Last Neanderthal: The Rise, Success, and Mysterious Extinction of Our Closest Human Relatives. Boulder, CO: Westview Press, 1999.
Appendix a Timeline of human evolution: 7 million years to present (source: Christian at 138)