Monday, 27 January 2014


Neandertals or Neanderthals, prehistoric humans who lived in Europe, the Middle East, and western Asia from about 200,000 to 28,000 years ago. Scientifically, they are usually classified as a separate species, Homo neanderthalensis. Although closely related to modern humans (Homo sapiens), Neandertals were physically distinct. Short and stocky in build, they had large, protruding faces, prominent brows, and low, sloping foreheads. Their brains, however, were fully as big as those of modern humans. The typical lifespan of Neandertals was much shorter than that of people today, with few individuals living beyond 40 years.
Neandertals have often been caricatured as clumsy, dim-witted brutes who walked with a slouch. This misconception emerged from faulty conclusions by the anthropologists who first studied Neandertal fossils. In fact, Neandertals walked completely upright without bent knees. Moreover, in recent years scientists have come to appreciate that Neandertals were remarkable in their achievements and sophistication. They used fire, made complex stone tools and weapons, wore clothing, and buried their dead. They successfully adapted to harsh, cold climates of the late Ice Age and survived as a species for more than 150,000 years—longer than modern humans have existed.
Neandertals were apparently the sole humans in Europe when the first members of Homo sapiens arrived there, probably from the Middle East, about 40,000 years ago. Just over 10,000 years after this event, Neandertals became extinct. Some scientists theorize that competition or conflict with modern humans played a role in the extinction of Neandertals, but this is a subject of debate. The exact reason for their disappearance remains a mystery.
The term Neandertal comes from the discovery in 1856 of human fossils in the Little Feldhofer Cave of the Neander Valley, near Düsseldorf in western Germany (tal means “valley” in German). These bones were the first to be recognized as an early type of human. Since then, archaeologists have discovered more fossils of Neandertals than of any other early human species. Because of this abundance of evidence, Neandertals are among the best understood of all our fossil relatives.
Neandertals were built on exactly the same basic body plan as modern humans are, but their skulls and skeletons reveal some significant differences. Their large brains were housed in long skulls (as measured front-to-back) with low foreheads and bulging rears, in contrast to the short skulls and high foreheads of modern humans. The brains of Neandertals were, on average, as large as those of modern humans, and all were within the Homo sapiens size range. In front, the face was quite forwardly positioned compared to the flatter face of modern humans. Neandertals had prominent brow ridges with a bony arch over each eye, and the cheekbones retreated sharply from a large nasal cavity (indicating a large nose). They had long and powerful jaws but no chin.
Neandertal skeletons show numerous differences from those of modern humans, notably in the pelvis and in the limb joints, which were large and robust. Most Neandertals were relatively short, with males standing about 1 m 60 cm (5 ft 3 in) tall, but some topped 1 m 83 cm (6 ft). Their short limbs and stocky bodies tended to minimize heat loss from the head and extremities and suggest an adaptation to extreme cold. The limb bones of Neandertals were rather thick-walled in comparison to our own, and joint surfaces were large. Just as we do, Neandertals differed a bit from place to place in stature and features.
In their heyday some 75,000 years ago, Neandertal groups occupied a vast region encompassing Europe and southwestern Asia, from the Atlantic coast to western Asia and the eastern Mediterranean. They adjusted with considerable success to the climatic extremes of the late Ice Age, when bitterly cold glacial periods alternated with warmer periods known as interglacials. During glacial periods, much of Europe was covered with thick ice sheets and the European plains were treeless steppes and tundra. But even in milder interglacial periods, Neandertals had to survive cold winters and long periods of food scarcity.
Most European Neandertal groups flourished in the sheltered valleys of northern Spain, southwestern France, and elsewhere in southern Europe, where caves and rock shelters often provided good winter homes. In southwestern Asia, other Neandertal groups adapted to arid, chilly conditions, where constant mobility was the key to survival. Some of these populations were more lightly built than their European relatives.
Most Neandertal fossils have been discovered in rock shelters or cave mouths, but this does not mean Neandertals did not camp in the open. Caves and rock shelters are simply more likely to preserve evidence of occupation than sites in the open. There are indications that Neandertals rigged up artificial shelters where required.
Like other human species before them, Neandertals were hunters and gatherers, living off the resources provided by nature. They almost certainly lived and hunted in small, nomadic groups that roamed over large territories. By all indications, Neandertals were expert hunters who relied on exceptional stalking skills to get close to animals of all sizes. Animal bones found at Neandertal sites suggest that they hunted most of the animals in their environment, including wild cattle, deer, horses, and reindeer. Many Neandertal skeletons display signs of healed broken limbs and other traumatic injuries resulting from hunting accidents or other mishaps.
Analyses of Neandertal bone chemistry suggest that Neandertals lived mostly on meat, but they did not depend on hunting alone. Scavenging of dead carcasses, rather than active hunting, might account for a proportion of the animal bones found at Neandertal living sites. Seeds and other plant remains found at Neandertal sites demonstrate that wild plant foods were an important part of their diet.
Evidence suggests that Neandertals might at least occasionally have practiced cannibalism, a behavior documented among the earliest humans in Europe 780,000 years ago. Neandertal bones from a cave in southeastern France show cut marks indicating they were scraped of flesh with stone knives.
The Neandertals made stone tools quite skillfully and relied on them for their survival. Triangular spear points may have been hafted (attached to a wooden handle or shaft) to make hunting weapons. Scrapers, hand axes, and backed knives (sharp flakes with one side dulled to fit comfortably in the hand) would have been highly effective for butchering animals and scraping hides for clothing or shelter. Sharp-edged chopper stones were probably used for cracking open animal bones to get at marrow. The cutting surfaces of Neandertal tools also show wear consistent with woodworking. Wood does not preserve well, and only a handful of wooden artifacts have been recovered from Neandertal sites. However, a pre-Neandertal find in Germany of finely-shaped throwing spears suggests that Neandertals would have made these too and thus have been quite sophisticated ambush-hunters.
Neandertals made stone tools by striking flakes from rock “cores.” The cores were carefully selected and prepared so that only a single blow was normally required to detach a flake. A number of relatively standardized flakes were sometimes produced from a single core. These sharp flakes served as “blanks” that were further worked and shaped into the desired tools. Suitable stone was sometimes rare, and often tools were sharpened and resharpened to make new tools, yielding a whole variety of shapes and sizes. Unlike the Cro-Magnons, their modern human successors, Neandertals rarely used bone or antler as materials for tool making.
Neandertals used this same basic toolmaking technology, termed Mousterian by archaeologists, for most of their existence. However, they later acquired a more advanced toolmaking technology, called Châtelperronian after where it occurred in France, characterized by long, thin stone “blades” and greater use of antler and bone. At one site, personal decorations made from teeth have been found. Scientists have debated the earliest dates for Châtelperronian culture. Most archaeological work has indicated a date of about 35,000 years ago for Châtelperronian artifacts—shortly after the arrival of modern humans in Europe. This date for Châtelperronian culture led some experts to suggest that Neandertals somehow learned how to make these tools from modern humans, who had a similar technology during this era. A study published in 2006, however, redated the main site in France to 44,000 years ago—thousands of years before modern humans are thought to have reached Europe. This revised date would imply that Neandertals likely invented Châtelperronian toolmaking technology independently.
Most experts believe that the Neandertals must have had clothing of some sort in order to survive the climate in Europe, which was at times severely cold. However, little is known about what type of clothing they wore. They could have easily made simple skin cloaks by scraping animal hides with stone tools, and they did make bone awls that would have served to pierce hides for binding. Neandertals never developed perforated bone needles, which would have allowed them to fashion tailored, layered clothing.
Neandertals also controlled fire. At some Neandertal sites, thick piles of ash and burned rocks attest to years of campfires burning. No evidence exists that reveals how Neandertals used fire, but it would have provided them with heat, light, and a way to cook food.
Neandertals were the first humans known to have buried their dead. Numerous burial pits have been discovered in the floors of caves and rock shelters, sometimes accompanied by stone tools or a few animal bones. At one Neandertal grave, in Shānīdār Cave in Iraq, large amounts of pollen were discovered, perhaps suggesting a burial with flowers. A Neandertal child skeleton from Teshik-Tash in the western foothills of the Himalayas lay in a pit surrounded by six pairs of mountain goat horns. At many other burial sites, Neandertal skeletons have their knees and arms drawn close to the chest in a fetal position, possibly but not necessarily indicating a ritual burial position.
To some authorities, these burials and grave items represent evidence that Neandertals practiced religious rituals, believed in the afterlife, and had the ability to think symbolically. Other experts challenge such interpretations as overly enthusiastic, and offer more mundane explanations. For example, stone tools and animal bones were common objects in Neandertal living sites and could have been buried in graves unintentionally, as part of the filling process. Neandertals may have buried their dead simply to avoid attracting unwelcome scavengers to their settlements, not because burials held symbolic importance. The flower pollen found in the Shānīdār grave could have been deposited by burrowing rodents.
The possibility that Neandertals used language, a hallmark of symbolic thought, has intrigued researchers for decades. Some scholars believe the Neandertals had fully articulate speech. Some support for this claim comes from a Neandertal skeleton discovered in Kebara, Israel. The skeleton still possesses its hyoid bone, a bone situated at the base of the tongue that affects the movement of the larynx, where speech originates. The Kebara Neandertal hyoid is identical to that of modern humans, suggesting these people were physically capable of articulate speech. While some studies of the base of the Neandertal skull suggest the larynx may have been positioned too high in the throat to produce articulate speech, the bending of the cranial base in earlier fossils suggests that the ability to produce the sounds of speech may have been present in human precursors well before Neandertal times.
Objects with possible symbolic connotations have been discovered at a few Neandertal sites, including pierced animal teeth that may have been used as pendants, incised bone fragments, and a polished plaque made from a mammoth tooth. Bone and tooth ornaments, including an elegant bone pendant, were found with Neandertal remains at Arcy-sur-Cure in central France. But the extreme rarity of these objects contrasts sharply with the remarkable abundance of symbolic and decorative artifacts—such as cave paintings, figurines, carvings, and beads—produced by the Cro-Magnons, the Neandertals’ successors in Europe. Thus, it seems likely that Neandertals did not have symbolic thought or language as we know it today, though their intuitive intelligence was probably highly developed.
The earliest fossil evidence for the human occupation of Europe comes from Ceprano in Italy, where a skullcap has been found that is thought to be around 900,000 years old. In the mid-1990s at the Gran Dolina site in the Atapuerca hills of northern Spain, archaeologists unearthed human fossils dated to 780,000 years ago. The Ceprano specimen has been assigned to its own species Homo cepranensis, and those from the Gran Dolina to the species Homo antecessor or Homo mauritanicus.
Between around 400,000 and 200,000 years ago, some human fossils in Europe show some of the features of Neandertals, but not all of them. The earliest of these fossils, dated to around 400,000 years ago, are from the Sima de los Huesos (“Pit of Bones”) cave site at Atapuerca near the much earlier Gran Dolina site. Thousands of human bones have been found in a pit in the cave, representing around 30 individuals—more ancient hominid bones collected in one place than found anywhere else in the world. These human fossils are contemporaneous with other fossils classified as Homo heidelbergensis. The Sima hominids are best regarded as the closest known relatives of the Neandertals, and are possibly their ancestors.
The Cro-Magnons, a group of early Homo sapiens, entered Europe about 40,000 years ago, a time when Neandertals were the region’s only human inhabitants. Neandertals and modern humans thus coexisted in Europe for more than 10,000 years. Did Neandertals interbreed with modern humans? Why did the Neandertals die out around 28,000 years ago while modern humans thrived?
Scientists disagree about whether Neandertals were a distinct species from modern humans. Largely because Neandertals were big-brained, some paleoanthropologists continue to regard them as a version of ourselves. They classify Neandertals as a subspecies of Homo sapiensHomo sapiens neanderthalensis—and anatomically modern humans as Homo sapiens sapiens. According to this school of thought, Neandertals and Cro-Magnons interbred, and anatomically distinctive Neandertal features were simply “swamped” genetically by waves of Cro-Magnons intruding into the Neandertals’ homeland. If true, some Neandertal genes probably survive today in modern humans of European descent.
Supporters of interbreeding between Neandertals and modern humans turn to fossil evidence; some late Neandertal fossils are said to look more “modern” than earlier ones, and some early moderns are said to have some “Neandertal-like” features. The claim that these fossils represent evidence of interbreeding is controversial and remains unproven. At a few sites there is evidence of a short-lived culture that combined Neandertal and Cro-Magnon elements, but this was probably achieved without biological intermixing.
The more we learn about Neandertals, the clearer it becomes that they deserve recognition as a species in their own right, Homo neanderthalensis. In a dramatic series of studies begun in the mid-1990s, scientists extracted fragments of deoxyribonucleic acid (DNA, the basic unit of heredity) from several Neandertal specimens and compared them to DNA from living humans. The early studies showed that Neandertal DNA is genetically distant from modern human DNA, falling well outside the range of variation seen among humans today.
In 2005 researchers announced plans to sequence the entire Neandertal genome. This project would allow scientists to compare the full set of chromosomes found in Neandertals with those present in modern humans. Genes associated with speech or other behavior characteristic of modern humans could be targeted for possible matches among Neandertals. New laboratory techniques can amplify small bits of DNA and identify individual genes much more rapidly than in the past. Both nuclear DNA and mitochondrial DNA from Neandertals are under study.
The first major results of the genome project were published in 2006, based on DNA extracted from a 38,000-year-old Neandertal bone found in Croatia. Two research teams used different techniques to analyze the ancient DNA, comparing it with DNA from modern humans and chimpanzees. One study concluded that the modern human and Neandertal lineages split around 500,000 years ago. The other gave a range of between 700,000 to 370,000 years ago for the separation. Both results are in line with estimates from earlier genetic work.
These large differences in genetic structure indicate that Neandertals could not have been ancestral to modern humans. Taken together, these genetic studies offered powerful evidence that Homo neanderthalensis was a fully individuated species.
If Neandertals and modern humans in Europe were indeed different species, it is difficult to see how they could have interbred. No biologically significant exchange of genes should have been possible. Nonetheless, some researchers have proposed that a least two genes that appeared in modern humans in the past 37,000 years might have resulted from interbreeding with Neandertals. Limited genetic exchange among different humans species cannot be totally excluded, but the issue will require much more study.
Recognition of Neandertals and modern humans as distinct also suggests that the two species competed for the same territory. How this competition played itself out is unknown, but the general pattern in Europe seems to have been one of abrupt replacement of Neandertals by moderns at site after site. The end result was the extinction of the Neandertals. Whether this extinction occurred because of direct conflict or indirect economic competition is not known, but a combination of these factors seems likely.
See also Human Evolution; Stone Age.

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