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John J. Shea Anthropology Department, State University of New York, Stony Brook
The origin
of modern humans and the fate of the Neanderthals are two of the most hotly
debated topics in paleoanthropology (Stringer 1996). Recent developments
in the archaeology of the Middle Paleolithic Levant, part of the East
Mediterranean including southern Turkey, Syria, Lebanon, Israel, Palestine,
Jordan, and northern Egypt (fig.1), are dramatically changing our perception
of Neanderthals. Once seen as dull-witted cavemen, new evidence suggests
Neanderthals were intelligent, adaptable, and highly effective predators.
Although many see Neanderthals as our possible ancestors, it is increasingly
clear that they competed with early modern humans for tens of thousands of
years in Europe and the Near East.
New research in Africa, Europe, and Asia suggests that the abrupt disappearance
of the Neanderthals and the sudden appearance of early anatomically-modern
humans throughout much of Western Eurasia after 47,000 BP is more than a
coincidence. The last fifteen years in particular have seen flourishing
scientific advances in areas such as improved radiometric dating techniques
and the recent recovery of Neanderthal DNA. These are making it increasingly
clear that the Levantine Neanderthals and early modern humans were probably
different species, indirectly competing with each other in the same ecological
niche. Further, the Levant appears to have shifted hands repeatedly between
Neanderthal and early modern human occupations until around 47,000 BP, after
which Neanderthal populations dwindled, culminating in their extinction by
28,000 BP. Concurrently, modern humans were expanding into western Eurasia,
replacing Neanderthals along the way.
Background: Neanderthal Fossils and Archaeology. “Neanderthal”
refers to a group of morphologically distinct human fossils found throughout
Western Eurasia dating to ca. 130,000-30,000 BP. They app ear to have evolved
in Europe from Homo heidelbergensis populations, such as those from
Sima de los Huesos (Atapuerca, Spain), Steinheim (Germany) and Petralona
(Greece). The principal Neanderthal fossils of the Levant come from the cave
sites of Tabun, Amud, Kebara, and Dederiyeh (fig.1), as well as Shanidar Cave in
northern Iraq (Trinkaus 1996). Neanderthals were ruggedly built, with thick
chests and relatively short limbs, a body shape today found among arctic
populations (Stringer and Gamble 1993). In comparison, early modern human
fossils older than 47,000 BP are found mainly in Africa, but also at two
cave sites in northern Israel, Skhul and Qafzeh (Bar-Yosef and Vandermeersch
1993). These fossils are also robust, but have thinner chests and relatively
long limbs, like those of modern-day humans in the tropics (Holliday 2000).
Fig.1: Map of the Levant, showing important sites mentioned
in the text (J. Shea)
Paleoanthropological models of Neanderthal-early modern human evolutionary
relationships vary substantively. At one extreme, proponents of
“multiregional continuity” regard Neanderthals as a geographically
distinct subspecies of Homo sapiens, one that was absorbed into expanding
modern human populations by interbreeding (Frayer et al. 1993). At the other
extreme are proponents of “replacement” who view Homo sapiens
as having originated in only one region, expanding from that region by
competitively displacing the Neanderthals without interbreeding (Stringer
1992). Some researchers hold intermediate positions, arguing for replacement
in some regions and continuity in others (Smith 1994). The crucial question,
though, of whether Neanderthals and early modern humans could have interbred
and produced both viable and fertile children (the definition of a species)
remains unanswered, and perhaps unanswerable. However, strands of DNA have
been recovered from Neanderthal fossils which suggest a lack of direct ancestry
between the two species (Höss 2000; Ovchinnikov et al. 2000, and this
issue). Conversely, recent claims argue that fossils of an Upper Paleolithic
child from Lagar Velho reflect a hybrid Neanderthal-modern human ancestor
(Duarte et al. 1999;
Zilhao
this issue).
Changing Models
of Levantine Middle Paleolithic Human Evolution: Until recently, the
Levant was seen as furnishing the strongest evidence for a biocultural transition
between the Neanderthals and early modern human populations. In the mid-1980s,
geophysicists had developed several methods, thermoluminescence, electron-spin
resonance, and uranium-series, for dating sites older than 40,000 BP that
provided revolutionary results. While estimated ages for the Levantine
Neanderthals were broadly comparable to those from Europe, between 65,000-47,000
BP, the new dating methods showed that the early modern humans from Skhul
and Qafzeh date to 130,000-80,000 BP, older than the Neanderthals who were
supposedly their ancestors (Valladas et al. 1998). Minimally, these new dates
call for a reinterpretation of Neanderthal vs. early modern human biological
and behavioral contrasts.
There are many similarities in the Neanderthals’ and early modern
humans’ a rchaeological records. Both lived in similar Mediterranean
woodland habitats and occupied karstic caves. Both hunted and gathered the
same range of animal species, such as aurochs (wild cattle) fallow deer,
wild boar, ibex, and mountain gazelle. Both made Middle Paleolithic stone
tools in similar ways. Such similarities are to be expected between closely
related hominids, but they do not necessarily imply a close social or cultural
relationship. Instead, evidence for evolutionarily significant behavioral
differences between Neanderthals and early modern humans is likely to be
subtle, reflected in the different strategies these humans used to accomplish
their settlement, subsistence, and social goals.
Fig.2: Neanderthal skull from Amud, Israel
Seasonality, Settlement and Mobility Strategies: Seasonality studies
indicate that Neanderthals and early modern humans used different
mobility strategies (Lieberman 1998). Cementum, the continuously growing
tissue that secures teeth in the skulls of herbivores, can tell us the season
of an animal’s death and hence, in archaeological contexts, the time
of year that humans hunted it and occupied the site (for a more detailed
explanation of how researchers use cementum, see Shea's article in Athena
Review Vol.2, no.4; pp.24-25). The teeth of herbivores (mainly gazelle)
associated with early modern remains at Skhul, Qafzeh, and Tabun Level C
preserved evidence for single-seasons of occupation (typically only during
winter). Teeth associated with Neanderthals at Tabun B a nd Kebara provided
evidence for multiseasonal occupations. Early modern humans appear to have
shifted their camp sites seasonally, perhaps moving as different resources
became available in different parts of the landscape. Neanderthals pursued
a different strategy, one in which optimal habitation sites were occupied
continuously for prolonged periods (or frequently re-occupied) and provisioned
by shifting emphasis among various local food sources. That these two strategies
were pursued in the same Mediterranean woodland habitat suggests that they
were not spurred on by environmental differences, but instead by behavioral
variations between Neanderthals and early modern humans.
Fig.3: Anatomically Modern Human skull from Skhul at
Mt. Carmel, Israel.
Lithic Artifacts and Hunting Strategies: Microscopic wear patterns
on Levantine Middle Paleolithic triangular flakes, especially “Levallois
points,” show they were used as armatures for thrusting spears (Shea
1988, 1997). At Umm el Tlel, Syria, a fragment of one such point was recently
found embedded in a neck vertebra of a wild ass (Boeda et al. 1999). Thrusting
spears are heavy weapons, and their brittle stone points would have to be
replaced often. It seems reasonable to expect that groups specializing in
partiucular larger game hunting, i.e., Neanderthals, used these and would
have assembled larger numbers of suitable replacement points at their habitation
sites than those (Homo sapiens) who used lighter weapons, such as
sharpened wooden spears and clubs, against a wider range of prey species
(Bleed 1986). And the archaeological record of the Middle Paleolithic Levant
seems to show this.
Burial and Mortuary Ritual: Contrasts between Neanderthal and early
modern human burials from the Levant provide a third line of evidence for
behavioral differences. Burial of the dead is often associated with ritual,
but it may have been practiced in the past for the more practical purpose
of minimizing carnivore visits to habitation sites. If burial was for the
latter reason alone, then there is no reason to expect objects immediately
near the skeleton to differ significantly from those in the surrounding
sediments. This seems to be true of all of the claimed Neanderthal
burials from the Levant. Even the famous “flower burial” from Shanidar,
long a mainstay of claims for Neanderthal mortuary ritual, may have been
caused by rodents (Meriones persica) storing flowers in their burrows
(Sommer 1999). Most of the early modern human skeletons from Skhul and Qafzeh
are also simple burials, but two notable exceptions, where skeletons were
found with unusual animal bones, may indicate that early modern humans practiced
different social strategies from those of Neanderthals.
Evolutionary Changes in Modern Human Behavior: Current fossil evidence
shows that only early modern humans were present in the Levant between
130,000-80,000 BP, and re-appear again after the Middle-Upper Paleolithic
Transition, around 47,000-40,000 BP. Only Neanderthal fossils appear in the
intervening period, 75,000-47,000 BP. Bar-Yosef (1988) has suggested that
the rapid onset of glacial conditions around 75,000 BP caused Neanderthal
populations to migrate south from montane western Asia into the Levant
corridor.Far from displaying a “transitional” population, the early
modern human fossils from the Levant seen to possess Neanderthal affinities
(Skhul and Qafzeh) date to before the first occurrence of Neanderthal fossils
in this region while human fossils from adjacent parts of Northeast Africa,
such as Tamrasa Hill I, that are contemporaneous with Levantine Neanderthals
preserve no trace of Neanderthal morphology (Vermeersch et al. 1998). Then,
around 45,000-35,000 BP, Neanderthal fossils cease to occur in the Levant
at exactly the point when Upper Paleolithic industries first appear in Israeli
and Lebanese cave sites (Bar-Yosef 1996). By 30,000 BP, Neanderthals continued
to practice Middle Paleolithic adaptations in a few isolated refuges, such
as southern Spain and western Asia. Shortly thereafter, Neanderthals became
extinct, replaced by Upper Paleolithic modern humans.
By contrasting the archaeological records of the Skhul/Qazfeh humans with
those of early Upper Paleolithic humans, it may be possible to identify those
behaviors that may have enabled the Upper Paleolithic humans to displace
the Neanderthals. Two prominent differences are the use of exosomatic symbols
and the use of projectile weapons.
Symbolic Culture: “Exosomatic symbols” allow modern humans
to creatively construct social and cultural identities that transcend actual
biological kinship (Wobst 1977). The best-documented early examples of symbolic
artifacts are bone, ivory and stone beads from “Aurignacian” early
Upper Paleolithic sites in Europe (White 1993), but perforated shells have
also been recovered from early Upper Paleolithic sites in the Levant (Gilead
1995). Although Middle Paleolithic Neanderthals and early modern humans are
associated with symbolic items such as red ochre pigment, tooth pendants,
exotic shells, and carved bones and stones, the use of these symbols appears
to have been on a relatively restricted geographic scale. Upper Paleolithic
symbolic artifacts, in contrast, occur at numerous sites within much larger
regions (Mellars 1995). This clearly implies a much larger potential audience
than that for Middle Paleolithic symbolic messages.
Subsistence Tools: The use of high-speed, low-mass projectile weapons,
such as javelins, spearthrower darts, and arrows, is an important component
of the Upper Paleolithic economic “revolution” (Knecht 1994) and
appear in the early Upper Paleolithic of the Levant in the form of aerodynamic
stone and bone points from Ksar Akil, Lebanon (Bergman 1981; Newcomer
1987).Weapons of this kind allow their users to kill targets from a safe
distance, minimizing the risk of attacking large, dangerous mammals. Because
these weapons depend more on throwing speed and aim than sheer physical force,
juveniles and females can use them as effectively as adult males, allowing
for a larger proportion of their population to participate in the large animal
food quest. If early Upper Paleolithic modern humans migrating out of the
African tropics were more experienced at using projectile weapons than
Neanderthals or the Skhul/Qafzeh humans, then they would have had a crucial
adaptive advantage.
Conclusion: The most interesting thing about the Levantine record
is that until 47,000 BP, there is no objective basis for predicting whether
Neanderthals or early modern humans would ultimately be the most successful,
and certainly no way to predict that modern humans would permanently replace
the Neanderthals. Because we know the Neanderthal fossil record so well,
relative to other hominid fossils, and because we know they became extinct,
there is a tendency to see Neanderthals as inevitable evolutionary
“losers.” However, studies of their fossils and their archaeological
record point to no obvious defects in their adaptations. Neanderthals and
their Homo heidelbergensis ancestors evolved and thrived between
300,000-30,000 years ago, nearly a quarter of a million years, in some of
the harshest and least hospitable habitats ever occupied by hominids. The
picture of the Neanderthals emerging from recent research is one of formidable
competitors, humans every bit as worthy of our interest and admiration as
our own direct ancestors.
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This is an abridged version of the article appearing on pp. 21-32 in Vol.2, No.4 of Athena
Review.
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