Scientists Date a Homo Sapiens Fossil at Ninety-Two Thousand Years

Date 1987-1988

When a team of scientists examined a modern-looking Homo sapiens fossil and determined its age to be ninety-two thousand years, the finding was startling because it doubled the length of time that modern humans had previously been known to exist.

Locale Gif Sur Yvette, France; Qafzeh cave, near Nazareth, Israel

Key Figures

• Hélène Valladas (fl. late twentieth century), French scientist at the Centre des Fables Radioactivités in France and leader of the radiometric team
• Bernard Vandermeersch (fl. late twentieth century), French physical anthropologist and archaeologist who excavated the Qafzeh site in Israel
• Dorothy Annie Elizabeth Garrod (1892-1968), English archaeologist who excavated the caves at Mount Carmel, Israel
• Arthur Keith (1866-1955), Scottish anatomist and physical anthropologist who analyzed the fossil remains from Mount Carmel
• Theodore Doney McCown (1908-1969), American physical archaeologist who assisted Garrod at Mount Carmel and assisted Keith in the analysis of the skeletal material
• René Victor Neuville (1899-1952), French archaeologist who discovered the cave at Qafzeh

Summary of Event

The origin of modern human beings has been a persistent and vexing problem for prehistorians. Part of the difficulty is that there is widespread disagreement over the relationship between modern humans and their closest extinct relative, Neanderthal man. Neanderthals differ from modern and some Archaic humans by the extreme robustness of their skeletons and by their heavy brow ridges, extremely large faces, and long and low skull caps. Neanderthals were once believed to have lived from approximately 100,000 to 50,000 years ago, while modern humans had been thought to have existed for 40,000 to 50,000 years. Although Neanderthals were originally assumed to have been the ancestors of modern humans, prehistorians now agree that they were too localized, too extreme, and too recent to have been forerunners of modern people.

Archaic fossil humans are less robust and make better candidates as ancestors of modern humans. These have been found in sub-Saharan Africa and also in the Middle East, where they overlap in both location and time with Neanderthals. No specimens of this type have been found in Europe.

Arguments regarding the origin of modern humans center on the issue of one ancestral group as opposed to many ancestral groups. One view assumes that modern humans evolved from many local Archaic types, including Neanderthal. A variation of this perspective holds that, while the ancestors of modern humans may have originated in one locality, they interbred with local peoples they met as they spread throughout the world. Both these views hold that this intermixture of genes explains the physical differences between modern populations.

Opposed to this view is the single-origin perspective, which maintains that earlier humans were replaced completely by physically and technologically more advanced members of a new group. The most favored homeland for this new and improved type is sub-Saharan Africa, where there are early examples of possible forerunners of modern humans, but where there is no known example of Neanderthals.

The region called Levant, which includes Israel, has been of considerable interest to holders of both of the theories just described because it forms a land bridge between Africa and the rest of the world. Any population moving from one region to the other had to pass through the Levant. This fact became particularly important when the first Neanderthal found outside Europe was discovered in Galilee in 1925.

Pursuing this lead, the English archaeologist Dorothy Annie Elizabeth Garrod excavated a series of caves on Mount Carmel, now in Israel, between 1929 and 1934. She was assisted by a young American, Theodore Doney McCown. In two of these caves, Tabun and Skhul, McCown discovered human remains with stone tools that had characteristics associated with Neanderthal remains.

Back in England, McCown worked with the eminent Scottish anthropologist Sir Arthur Keith to analyze the bones. The fossils at Skhul, although Archaic, resembled modern humans in most characteristics; those at Tabun resembled Neanderthals, although these skulls’ features were less exaggerated than those of classic Neanderthals.

Overlapping with Garrod’s excavations at Mount Carmel were those by René Victor Neuville from the French consulate at Jerusalem. Neuville excavated the Qafzeh cave between 1933 and 1935, finding the remains of five individuals. Unfortunately, World War II (1939-1945) intervened, followed by the Israeli-Arab conflict of 1947. Neuville died without analyzing his material. From 1965 to 1975, the French archaeologist and physical anthropologist Bernard Vandermeersch continued Neuville’s excavations, finding the remains of eight individuals who resembled the non-Neanderthals from Skhul.

The meaning of these remains was interpreted variously. McCown believed that the Mount Carmel population was in the process of diverging into two groups from a more generalized ancestor and that neither were modern humans. Others thought that the fossils represented a cross between Neanderthals and modern humans. A few others thought that Neanderthals had been caught in the act of evolving into modern humans.

A major problem in making sense of the Levant fields lies in the inaccuracy of dates. Radiocarbon dating methods do not help because they are inaccurate for sites as old as Qafzeh, Tabun, or Skhul. Until recently, all that could be known was that humans of some sort had been in the Levant more than sixty thousand years ago and had lived there for an undetermined time.

Another method of dating, thermoluminescence, helped to clarify the dates. Thermoluminescent dating is used on objects such as pottery that were “fired” or heated during the time that they were used. When such objects are heated again in the laboratory, photons are released, producing thermoluminescence, or glow. The longer ago the object was fired, the more glow results. The greater the glow, the older the object. Thermoluminescence can be used to date much older material than can radiocarbon methods; unfortunately, it is not as accurate as radiocarbon.

The first objects to be dated by thermoluminescence in the Levant were burnt flints from the Neanderthal sites at Kebara. The dating was done by a French-Israeli team headed by Hélène Valladas, with results being published in 1987. The Neanderthal site was dated at sixty thousand years; if the date is correct, Neanderthals were in the Middle East much later than had been thought.

In 1988, a team led by Valladas published a thermoluminescence date of ninety-two thousand years from Qafzeh. If this date is correct, then there were forerunners of modern humans living in the Levant twice as long ago as had been suspected. Furthermore, these individuals were there either before or at the same time as the Neanderthals.

Significance

Because thermoluminescence gives only a rough estimate, confirmation by another form of dating is desirable. In the meantime, there have been two dominant reactions by scientists. Those subscribing to the single-origin, out-of-Africa model see the Qafzeh date as confirmation of this hypothesis. Others, such as the American Milford Wolpoff, dispute this assessment. Wolpoff believes that Neanderthals contributed to the genetic makeup of modern Europeans. He points out that the late Neanderthals in Europe are more like modern Europeans in some respects than are the more modern-looking fossils from Skhul or Qafzeh.

The dates from Qafzeh have been adjusted and continue to raises many questions—particularly between those paleoanthropologists who believe that Neanderthals were basically replaced by modern humans and those who think the relationship between the species is more complex and may involve genetic exchange. Paleoanthropologists such as Richard Klein argue against genetic exchange; Wolpoff and his colleagues cite evidence for a more nuanced interpretation of the evidence that allows for an intermingling of gene pools.

Bibliography

Finlayson, Clive. Neanderthals and Modern Humans: An Ecological and Evolutionary Perspective. New York: Cambridge University Press, 2004. Argues that Neanderthals went extinct because of their inability to adapt to changing environmental conditions rather than as the result of direct competition with Homo sapiens. Includes bibliographic references and index.

Garrod, D. A. E., and Dorothea Bate. The Stone Age of Mount Carmel. Vol. 1. Oxford, England: Clarendon Press, 1937. Very detailed work provides information on the ecology of the Mount Carmel archaeological site, the excavation methods, and the findings. Garrod’s work was outstanding for its time. Includes illustrations.

Holloway, Ralph L. “The Poor Brain of Homo sapiens neanderthalensis: See What You Please.” In Ancestors: The Hard Evidence, edited by Eric Delson. New York: Alan R. Liss, 1985. Amusing article expresses sympathy toward Neanderthal man. This and other contributions to the volume cover the general issue of the place of the Neanderthal in human evolution.

Jordan, Paul. Neanderthal: Neanderthal Man and the Story of Human Origins. Stroud, Gloucestershire, England: Sutton, 2001. Explores the evidence to present a picture of the world in which Neanderthals lived and their relationship to Homo sapiens. Includes illustrations and index.

Tattersall, Ian. The Last Neanderthal: The Rise, Success, and Mysterious Extinction of Our Closest Human Relatives. Rev. ed. Boulder, Colo.: Westview Press, 1999. Focuses on the relationship between Neanderthals and modern humans. Provides information on fossil dating and other background for lay readers. Illustrated.

Valladas, H., et al. “Thermoluminescence Dating of Mousterian ’Proto-Cro-Magnon’ Remains from Israel and the Origin of Modern Man.” Nature 331 (February 18, 1988): 614-616. This is the article that first announced the early date at Qafzeh. Presents the data in a technical manner, but the conclusions are easily understandable. Includes charts and bibliography.