THE SECRET LIFE OF THE NEANDERTHAL
The band of Neanderthals stopped outside the cave, and a
lone male peered in.
Looking around, he noticed that previous occupants, a taller, more
graceful
group, had left some remnants: smoldering coals, scattered garbage, and a
smooth,
shell-shaped pendant, purpose unknown. Finding no food, the
Neanderthals trekked on,
traversing miles of rocky terrain in less than a day.
By late afternoon, they'd begun to
track a goat. One of the males plunged on
top of the animal, wounding it with his crude
but heavy spear; the animal
thrashed, but the male hung on until the goat died. Uttering a
series of
meaningful grunts, the Neanderthal band settled down tor the night. One of the
females built a fire, while another scraped the hide with a sharpened stone. A
gray-haired
male propped his arthritic leg above a grassy knoll. Devouring the
remains of dinner, this
Neanderthal family had no way of knowing their future:
The rest of their stay on Earth
would be arduous and brief.
A time machine and camcorder top the wish list of every
scientist hoping to
unravel the secret life of the Neanderthals-long viewed as a bumbling
people who
evolved rapidly (and thankfully) into our direct ancestors. But though today's
paleoanthropologists lack the knack of time travel, they have recently acquired
access to
the next best thing: remarkable new dating technology that is slowly
bringing the life and
times of early hominids into bold relief. Based on
state-of-the-art dating techniques such
as thermoluminescence and electron spin
resonance, researchers have come up with an
increasingly detailed picture of the
Neanderthals and how they lived.
No longer viewed as an
evolutionary lout, the Neanderthal depicted today is a
kinder, gentler, more successful
individual with a range of unique cultural
characteristics including sophisticated hunting
practices and an intimate and
elaborate social life.
In addition, paleoanthropologists now
believe that Neanderthals coexisted with
our direct ancestors, early modern humans, for a
longer time span than ever
before suspected. This revelation has thrown a monkey wrench
into the story of
hominid evolution, for if Neanderthals were not our direct ancestors,
then who
were they?
Scientists have been puzzling over this question since 1856, when quarry
workers
in the Neander Valley near Dusseldorf, Germany, found pieces of skull in the
rock.
Considering the way quarry workers go at limestone with picks and shovels
(not at all like
modern archaeologists, who tiptoe about with scalpels and
toothbrushes), it's a wonder that
any fossils remained. As University of
Chicago anthropologist Richard G. Klein tells the
story, the quarry owner
thought the bones came from a bear, but he turned them over to Carl
Fuhlrott, a
local schoolteacher, who pronounced them human, albeit unusual.
Further
discoveries over the next 120 years ensured Neanderthals a place right
next to modern
humans on the evolutionary continuum. According to early
paleoanthropologists, hominid
evolution occurred incrementally, with the
Neanderthal just one of many forms that led to
humans today.
As more Neanderthal remains were unearthed, anthropologists also pieced
together
startling aspects of Neanderthal life. By the 1950's, researchers could cite
definitive
fossil evidence of tool use, fire use, and hunting and gathering
techniques. And in
perhaps the most extraordinary find of that decade,
archaeologist Ralph Solecki unearthed a
Neanderthal skeleton covered with pollen
at the Shanidar site in Iraq. The so-called
flower burial sparked a debate
still unsettled today. The hard-liners argued that
Neanderthals buried their
dead only to discourage scavengers and eliminate odor. The
flower spores, they
held, had drifted into the graves purely by chance. But a new group of
researchers, increasingly convinced of Neanderthals' basic humanity, cited the
pollen as
evidence of a ritual Neanderthal burial in which survivors draped
flowers over the
deceased.
Evidence for the new and improved Neanderthal, one that inhabited the earth for
at least 100,000 years and lived side by side with early modern man, has been
accumulating
since 1980, when archaeologist Eitan Tchernov of Hebrew University
in Jerusalem started
dating the hominid remains found in three Israeli caves.
Since Tchernov could find no
dating techniques appropriate to the task at hand,
he devised a method of his own. By
approximating the dates of rodent bones
found in the same layer as human bones, he created
a biostratigraphy, an
evolutionary time chart based on fossils. Using biostratigraphy,
Tchernov and
Ofer Bar-Yosef, now a professor of anthropology at Harvard University, set the
ages of the Homo sapiens found in the Qafzeh and Skhul caves at 80,000 to
100,000 years
old, about twice as old as anyone suspected. They dated the
Neanderthal-like remains found
in the third cave, Kebara, at 50,000 years.
According to these figures, Neanderthals were
not ancestral to us at all.
Anthropologists immediately protested the accuracy of these
dates, saying the
biostratigraphy did not provide reliable information. However, in the
past few
years, two new techniques have confirmed the Israeli results.
One technique, called
thermoluminescence (TL), is particularly valuable for
dating nonorganic artifacts such as
burnt rocks and tools. The TL technique
works because objects accumulate electrons over
time, yet release electrons
whenever they are burned. An accumulation of electrons may be
measured by the
intensity of light an object emits when it is burned. By heating a
previously
burnt object-for instance, a flint fired in a Neanderthal hearth a hundred
thousand
years ago-and then measuring the energy emitted, researchers can
estimate the time that has
passed since the object was burnt the first time
around.
Experienced with TL, French
physicist Helene Valladas of the French National
Center for Scientific Research decided to
help the Israelis out. Dating
prehistoric flints from the three caves with the help of this
precise technique,
Valladas's findings were clear: Flints used by prehistoric Homo sapiens
at
Qafzeh were about 92,000 years old, while flints used by Neanderthals at Kebara
were much
younger-50,000 to 60,000 years old, at most.
The dates were also confirmed for organic
materials such as tooth enamel, bone,
or fossilized pieces of grain, thanks to another
high-tech method known as
electron spin resonance, or ESR. In ESR dating,
paleoanthropologists send a
sliver of material to the laboratory, where physicists grind it
up and expose it
to a strong magnetic field. The magnetic field reacts in direct
proportion to
the number of trapped electrons that a sample contains. The older the
fossil,
the more upset the magnetic field becomes.
To Tchernov and Bar-Yosef's delight, ESR
dating provided further support for
their dates. Their conclusion: Neanderthals did not
lead to early modern humans
but, rather, were their counterparts. "Modern-looking hominids
were
contemporary with the Neanderthals," says Bar-Yosef, "in the same way we are
contemporary
with people in Paris."
Because Neanderthals and humans are not directly related, it makes
sense that
their fossils seem distinct, even to the untrained eye. According to Lewis
Binford,
professor of anthropology at Southern Methodist University, the
Neanderthal skeleton looks
as though someone took a human skeleton and compacted
it into a shorter, broader frame. A
skull with a jutting brow topped this
stocky body, obviously built to maximize endurance
and resist bone damage. "Our
anatomy is that of a walker; the Neanderthals' was that of a
gymnast," says
Binford. "Their whole way of coping with the world was action, not tools."
Adds
Robert Franciscus, a doctoral student in anthropology at the University of New
Mexico,
"Neanderthals Were really using their bodies. Compared to them, modern
humans are
basically wimps."
But new theories and research techniques now go beyond the merely
obvious,
helping researchers flesh out some of the Neanderthals' best-kept physical
secrets
as well. According to Franciscus, for instance, the robust Neanderthal
body may have
served as a blanket of warmth against the cold, obviating any need
for fitted clothing.
Instead, Neanderthals probably relied on animal hides and
their truncated limbs and broad
noses to protect them from the frigid weather of
the Ice Age.
In fact, Franciscus has shown
in a recent study, Neanderthals living in colder
climates had abbreviated limbs. To reach
this conclusion, he measured the
brachial indices of their arms-the relative length of the
forearm to the rest of
the limb-and found that as warmth increased, limb length increased,
Interestingly enough, notes Franciscus, legs did not show as much regional
disparity as
arms. "Perhaps with their legs, the Neanderthals were responding
less to climatic stresses
than biomechanical ones," Franciscus says.
The Neanderthals' diminutive bodies suggest that
they may have suffered not just
from climatic stress, but also from nutritional stress,
according to Mary Ursula
Brennan, an anthropologist at New York University. Originally
trained as a
nurse, Brennan drew on modern nutritional knowledge to recreate the health of
early hominids from their dental remains.
If people do not receive sufficient nutrients in
the first seven years of their
lives, Brennan explains, their teeth do not develop fully, a
condition known as
hypoplasia. Aware that this health problem might show up in our
prehistoric
predecessors, Brennan wound up toting an X-ray machine the size of a bread box
throughout France. Her mission: X-raying hominid dental remains in museum
storage areas to
check for hypoplasia. Of the more than 300 Neanderthals she
has tested, 40 percent
suffered from hypoplasia, a good indication that
resources were scarce. The early moderns
showed a hypoplasia rate of only about
30 percent. Further evidence came from a small
sample of Neanderthals she
studied who were on average about four inches shorter than their
successors.
"Neanderthals' short stature may have been an adaptation to low nutrient
availability,"
Brennan concludes. "If they were living in areas where there was
not enough food, people
who needed fewer calories would survive because they
were receiving sufficient nutrition.
People born with genes for tallness would
require more calories and die. So within a few
generations, everyone's
shorter."
While resources may have been scarce, bones found near
Neanderthal remains
indicate that these individuals did manage to find some sustenance.
Based on the
diets of modern hunter-gatherer societies, paleoanthropologists believe the
Neanderthals would have subsisted on plant foods supplemented with meat. Some
anthropologists
speculate that Neanderthals were "hunter-blunderers" who
scavenged the landscape. But
according to the latest research, Neanderthals
were persistent hunters who downed their
prey by brute force, This conclusion
comes from University of Michigan anthropologist
Loring Brace, who has done a
detailed study of skeletal and muscular stress in both
Neanderthals and Homo
sapiens to see which areas would be most likely to break in an
encounter. He
discovered the Neanderthal skeleton is adapted to resist such injuries as
broken
bones or dislocated shoulders, which would help them triumph in a battle of
strength.
Brace concluded that Neanderthals wrestled their prey to death. "The
Neanderthals were
put together on a heroic scale," Brace says. "For that to
have been maintained, there have
to have been hunting stresses. They must have
literally come to grips with the family
dinner."
Other recent studies have attempted to trace the life cycle of Neanderthals,
following
individuals from birth to death. Erik Trinkaus, professor of
anthropology at the
University of New Mexico, for instance, has analyzed about
20 complete Neanderthal
skeletons as well as fragments from other skeletons.
Using a technique known as
histomorphic metric analysis, Trinkaus ground up thin
slices of Neanderthal bone and placed
the resulting powder on slides under a
microscope. Trinkaus checked the bone powder for
signs of maturity. By
comparing the maturity of the Neanderthal bones with that of mammals
alive
today, Trinkaus estimated the age of each skeleton upon death. A definitive
pattern
emerged: Neanderthals rarely lived more than 40 years, with both sexes
dying at the end of
the female's reproductive cycle.
"What you have, then, is no postmenopausal survival,"
Franciscus says. "Most of
all, there would have been no grandparenting." In modern
hunter-gatherer
societies, grandparents lend a much-needed hand with child rearing.
Without
grandparents to help care for them, Neanderthal children might have been more
precocious
than their early modern counterparts, Franciscus suggests.
The absence of grandparents, say
other researchers, would have ramifications for
the society as a whole. In modern
hunter-gatherer societies the elderly are
responsible for passing on knowledge of the
environment and religious lore, says
anthropologist Randall White of New York University.
"The idea that you have a
Neanderthal group composed of people only to age forty means you
have a group of
a radically different social fabric. You're missing an entire generation."
But the overriding question when it comes to Neanderthal relationships for many
people
remains where they should hang on our family tree. Two years ago a group
of Berkeley
scientists thought they had shown we still had Neanderthal genes.
Today anthropologists
are not sure. Did the Neanderthals interbreed with the
early modern humans who shared
their land for at least 10,000 years? Or did
Neanderthals have no interaction with modern
humans until, ultimately, the
humans wiped them out?
Physical distinctions would have been a
sufficient obstacle to interbreeding
between humans and Neanderthals, says NYU's White.
Modern baboon species-which
never interbreed-show fewer skeletal differences than
Neanderthals and Homo
sapiens, he points out. This comparison supports the hypothesis that
Neanderthals did not become integrated into our gene pool.
Adds Tchernov, "Perhaps early
modern humans and Neanderthals were separated by
such profound cultural differences they
did not interbreed at all."
Even if there was no genetic crossover, no interbreeding, adds
Bar-Yosef, we
still don't need bloody scenarios to account for the Neanderthals' demise.
"Simple inability to compete with modern humans in terms of finding food and
shelter and
reproducing could have finished Neanderthals off once and for all."
Yet because no
clear-cut answers exist, researchers in the field may allow their
biases to color their
perception. Bar-Yosef charges that some of his colleagues
are "Westerncentric," preventing
them from accepting that Neanderthals and our
ancestors belonged to the same species. "Our
image of early Homo sapiens, based
on the concept of a man painting in a cave, is too
limited," he says. "It's
only particular to certain parts of Europe. What was happening
in the rest of
the world?"
Bar-Yosef contends that Western anthropologists may be all too
quick to assume
that Neanderthals contributed nothing to our gene pool, mostly because they
do
not want to admit a relationship with somewhat unsavory hominids.
Milford H, Wolpoff of
the University of Michigan at Ann Arbor takes an even
harder line, vehemently insisting
that Neanderthal genes did flow into the
evolutionary mainstream. Part of the proof, he
says, is as plain as the noses
on the faces of Charles de Gaulle, Jimmy Durante, or any
number of British
knights. "These large noses are Neanderthal features," Wolpoff asserts.
"If all
modern humans descended from a group of Africans who began migrating northward
between
one hundred and two hundred thousand years ago, as some anthropologists
claim, I am
hard-pressed to explain the origin of these noses. No African,
ancient or modern, has a
nose like that."
Perhaps it is the subtle familiarity of the Neanderthal face that
continues to
enthrall us today. Scientists are not the only ones to let emotions dictate
their view of Neanderthals. Erik Trinkaus, who once wrote what he refers to as
a
.,pedestrian" dissertation on the structure of Neanderthal feet, says the
general public
also reads the evolutionary record selectively.
"People really seem to want to claim the
Neanderthals as relatives," Trinkaus
says. "Their fossils have been known for almost one
hundred fifty years, but
our picture of them changes with the times: In the 1930's very few
people
thought the Neanderthals were cannibals, though there was some evidence for that
belief.
Then, in the 1940's, in the wake of World War 11, without any new fossil
evidence,
Neanderthals were turned into cannibals to explain the nastiness of
the Nuremberg trials.
Hollywood in the 1950's perpetuated a brutish caricature
of Neanderthals. And during the
1960's and 1970's, Neanderthals became flower
children after the Shanidar Cave discovery."
But no matter who the Neanderthals were and where they went, one thing is for
sure: Their
impact on the environment was minimal. Says White, "They were never
milking the
environment for more than it would give them. In some ways you can
argue they were more
successful than their successors in the Upper Paleolithic
or ourselves."