Hominids as meat-eaters
Hiking in the Okavango Delta in the Southern African country
of Botswana some years ago, two friends and I came across
a badly-injured buffalo bull. The animal’s stomach and
testicles had been raked open, and a short length of intestine
was looped over one of his horns. (That loop might, we decided,
have come from the lion which had inflicted the buffalo’s
wounds.) It’s easy to let nature take its course when
you’re at a decent remove, but this animal was dragging
the contents of his abdominal cavity over the grass right
in front of us. After a short debate on ethics, and on the
rules of the Moremi Game Reserve, the ranger-guide accompanying
us acceded to our request to shoot it. Like a subway passenger
surprised by a lurching start, the bull stumbled sideways
as the bullet hit his shoulder. He regained his footing, however,
and stood there looking just as distressed as he had before.
I asked the ranger if he was going to give the animal another
round, but was told that the ammunition was expensive, and
that one was going to be enough. Sure enough, the buffalo
started relaxing and looking sleepy. After a minute or so,
he lay down on his side. We let a decent interval go by before
throwing stones at him to make sure he was dead.
After a further debate on ethics and the rules of the Moremi
Game Reserve, I took a knife out of my backpack and cut a
chunk of steak from next to the animal’s spine. I had
to give the handle of that knife several hard punches with
the heel of my hand to get its point through the buffalo’s
tough, sparsely-haired skin, and wonder, as I write this,
whether the crystalline edge of a freshly-struck Oldowan flake
might not have done a better job.
Muscle-fibers on the cut edges of the meat were still twisting
as I wrapped it in newspaper and stowed it in my backpack.
We resumed our hike, and set up camp about four miles further
on. It was getting dark by this time, and we made a fire,
barbecuing the meat on a bed of thornwood embers. In a restaurant
those steaks might have been sent back for being too tough,
but their taste and flavor were so marvelous that a general
realization dawned that we hadn’t taken enough. As we
walked back to the carcass at five o’ clock the next
morning to see what had become of to it, wishful thinking
was telling me that I might be able to get some more.
There was, however, almost literally nothing left of the
buffalo. All we could see was a greasy stretch of flattened
grass where it had been lying, a dark patch where its blood
had soaked into the earth, and a few small fragments of bone.
The animal’s head itself, with its massive horns, was
gone, as were the spine, and all the other large bones. The
bush was dense at that spot, so some of those big body-parts
could have been hidden close by, but it’s as likely
that they’d actually been eaten. Here’s what Richard
Estes’ Safari Companion tells us about the
way the spotted hyena Crocuta crocuta deals with
bones:
Utilizes carcasses of large vertebrates
more efficiently than other carnivores, which waste up to
40% of their kills. Eats everything but rumen contents and
horn-bosses of the biggest antelopes.... Bones, horns, hooves,
even teeth are digested completely within 24 hours.
* * *
In the same layers as those which contain the earliest stone
cutting-tools found to date, cutmarked bones show, as we saw
in the previous chapter, that hominids were using those tools
to butcher the carcasses of medium- to large-sized ungulates.
We’ll deal, presently, with the issue of whether hominids
gained access to those carcasses by scavenging, or by doing
the killing themselves. For now we can content ourselves with
the non-controversial fact that, by 2.5 million years ago,
at least some hominids were eating the meat of large animals.
Antelopes aren’t generally meat-eaters, but some duikers
augment their fruit-centered vegetarian diets with the flesh
of small vertebrates. The order of which humans are members,
the primates, is not, in general, a meat-eating group either,
but some of its members have the same kind of “anomalous”
liking for meat as duikers do. These include humans, chimpanzees
and baboons on the “catarrhine” or Old World side
of the family, and capuchin monkeys on the “platyrhine”
or New World side. The fact that meat-eating is an exceptional
and relatively recent practice in the primate order, is reflected
in the fact that primate body-structures aren’t adapted
to it in any obvious way. Even though humans eat a relatively
large amount of meat, they still have the comparatively broad,
flat cheek-teeth that were evolved to process a diet dominated
by fibrous plant material, rather than the “carnassial”
or meat-cutting ones possessed by true carnivores like cats.
In the nineteen-fifties and early sixties it was still widely
assumed that the closest relatives of our species –
gorillas and chimpanzees – were pure vegetarians. It
was generally accepted, therefore, that the human family must
have started eating meat after it had split off from the gorilla-chimpanzee
line. That “post-split” incorporation of meat
into the human diet was thought, at the time, to have been
a revolutionary and momentous innovation – one that
had, in the words of a 1963 conference paper, “triggered
human evolution, and propelled man to the creature he is today.”
It was then discovered that chimpanzees are also meat-eaters.
When Jane Goodall first reported this fact, it was thought
that she’d witnessed an aberrant phenomenon –
one which was peculiar, perhaps, to the Gombe Stream area
in which her observations were made. It only sank in gradually
that all bands of the species Pan troglodytes contain
individuals who hunt animals and eat their flesh on a regular
basis. Troglodytes’ close relative, Pan
paniscus, the bonobo, still thought of as a vegetarian
long after the meat-eating ways of the former became known,
is now known to kill and eat flying squirrels and infant duikers.
The main study-group of chimps in Gombe Stream National Park
in Tanzania, consisting of about 45 individuals, is estimated
to eat over 1,000 lb. of meat per year – i.e. just over
20 lb. of meat per chimp. As much as half of this annual intake
is consumed during the two dry-season months of August and
September, a time when plant-food becomes relatively scarce,
and chimpanzee body-weights go down.
Most but not all hunting is done by male chimpanzees. Chimps
have larger canine teeth than early hominids had, but they
seldom if ever use those teeth to kill their prey. They get
a firm hold on the animal, rather, – usually by the
back legs – and flail it to death against the ground
or a tree trunk. Chimpanzees who end up in control of a carcass,
sometimes share pieces of it with hunting participants, political
allies and/or potential sexual partners. Craig Stanford of
the University of Southern California reports that most prey
animals are caught by co-operative action at Gombe Stream.
Some two thousand miles north-west of Tanzania’s Gombe
Stream, in the Ivory Coast’s Tai forest, Christophe
Boesch has observed an equally high degree of co-operation
in chimpanzee hunts.
To date, chimpanzees have been seen to eat the meat of between
thirty and forty vertebrate species. At Gombe Stream the young
of bushbucks, duikers and bush pigs appear on their menu.
When her baby son was living with her at Gombe, Jane Goodall
took special precautions to protect him, because, even though
it had happened a considerable time before her arrival, chimpanzees
were reliably reported to have killed at least two human infants
in that area for food. The Gombe chimps also kill young baboons,
but colobus monkeys are by far their most commonly-taken prey.
Most of their mammalian prey consists of immature individuals,
but some 25% of the colobuses they kill are adults. Craig
Stanford estimates that Gombe’s main study-group of
chimps kills an astonishing 20% of the colobus monkeys living
in their eighteen-square-kilometer hunting range in an average
year. “...[C]himpanzees,” he concludes, “may
be among the most important predators of certain prey species
in the African ecosystems in which they live.”
* * *
While the anthropological world was absorbing this “chimps
are effective predators” revelation, comparisons of
blood proteins were establishing another new realization:
chimpanzees and humans are each other’s closest relatives.
(The chimp-human line had, in other words, split off from
the ancestors of gorillas before it had split into its separate
human and chimp branches.)
These two insights– that chimps and humans are each
other’s closest relatives and that both species eat
meat – put the origin of human meat-eating in a new
light. It’s still thinkable that the human
family “invented” meat-eating after its split
from the chimp family, (and that chimps had thereafter “invented”
it independently of us) but the simpler and more likely explanation
is that the common ancestor of humans and chimps originated
meat-eating before the split, and then passed that adaptation
on to its descendant species. If this is the way things happened,
then the species from which chimpanzees and humans are descended,
would almost certainly have started its meat-eating career
by hunting small animals the way chimpanzees still do, rather
than as scavengers.
The earliest direct evidence of meat-eating by our family
comes, as we saw in the previous chapter, from the butchered
bones of medium-to-large-sized ungulates in the 2.5-2.6 million-year-old
horizon at Bouri and Gona. The hominid remains found at different
localities within that horizon at Bouri, have been assigned
to be a single species which its discoverers named Australopithecus
garhi. You may recall that the tool-scratched lower jaw
of a “medium-sized alcelaphine antelope” was one
of the cut-marked remains found at that horizon. (Alcelaphines
are, as we’ve seen, antelopes in the hartebeest-wildebeest
family.) A medium-sized alcelaphine like the hirola or “Hunter’s
antelope” weighs around 160 lb. The cutmarked femur
of a hipparion or three-toed horse found in close proximity
to the jaw, represented a species that would probably have
been as least as big as a hirola. The butchered “large
bovid” tibia found some 200 yards from the alcelaphine
jaw represents, presumably, a still larger animal. (Oryxes,
by no means the largest of the bovids, can weigh 400 lb.)
Back in the 1960s, stone tools had been discovered in association
with the bones of even larger animals at Olduvai gorge in
Tanzania in layers just under two million years old. Together
with rodent, tortoise, catfish and mollusk remains, 1.8 million-year
old deposits at Olduvai contain the butchered bones of not
only antelopes and buffaloes, but of mammals as large as rhinos,
hippos and elephants.
Raymond Dart was convinced that his little australopithecines
could kill Africa’s largest animals. “The animals
slain by this man-ape were,” he insisted, “neither
all small or slow; they were huge and active.” Dart’s
idea that australopithecine hominids hunted and ate other
animals was, as I’ll try to show in this chapter, correct.
It’s only his assumption that australopithecines hunted
Africa’s biggest animals – its elephants,
hippos and rhinos – that requires qualification. When
Dart made that assumption, it wasn’t yet known that
one of the australopithecine hominids was, by the beginning
of the Pleistocene, undergoing an increase in body-size that
was transforming it into Homo erectus – a species
that was, by about 1.7 million years ago, to supplant both
the australopithecine species which gave rise to it and any
other gracile australopithecine species that may have been
around at that time. As we’ll see presently, therefore,
the hominids who were hunting elephant-sized animals near
the beginning of the Pleistocene may no longer have been australopithecines.
* * *
By the 1980s a reaction had, as we’ve seen, set in
against Dart’s view that the australopithecines could
have hunted other animals. It began in 1981 when Bob Brain’s
book, The Hunters or the Hunted? An introduction to African
Cave Taphonomy, demonstrated, as we saw in Chapter 8,
that the fossilized bone fragments at Makapansgat were not
(as Dart thought they were) selected and modified for use
as tools and weapons. The “modifications” which
had, in Dart’s mind, turned them into daggers, blades,
scrapers, clubs and axes were, Brain demonstrated, consistent
with the effects of chewing by animals such as hyenas and
porcupines.
Lewis Binford’s Ancient Bones and Modern Myths,
which appeared in the same year as Brain’s book, struck
another blow against the idea that early members of the human
family could have hunted other animals. It suggested that
the stone tools and the animal bones which had been found
together at places like Olduvai, might have brought together
coincidentally by, say, the action of flowing water.
The mere fact of spatial proximity did not, in Binford’s
view, amount to proof that such tools had been used to butcher
the bones they were found with. The proof that Binford was
demanding was to emerge, however, soon after the appearance
of Ancient Bones. Henry Bunn of the University of Wisconsin
identified cut-marks on bones found on the Karari escarpment
in Northern Kenya’s Koobi Fora district – cuts
that could only have been made by hominids using stone tools
to slice through the ligaments attached those bones, and carve
flesh off them. Soon afterward, Pat Shipman and Richard Potts
found similar marks on bones from other sites in Kenya and
in Tanzania.
Did the discovery of these cut-marks turn things around,
and convince the anthropological community that early hominids
did, after all, have the capability of hunting large
animals? The answer to that question is “no.”
From about 1980 until very recently, it has been, as Robin
Dennell put it in a 1997 comment in Science, “profoundly
unfashionable” to talk about big game hunting, or indeed
any kind of hunting, by early humans. “Nowadays,”
Ian Tattersall could still tell us in his 1998 Becoming
Human, “the notion of active, early human hunting
of sizeable mammals has largely been discarded...”
The “early humans couldn’t hunt” theory
espoused by people like Tattersall and Binford didn’t
only deny that the australopithecine hominids could
hunt – almost everybody accepted that until the 2.5
million-year-old butchered bones we talked about in the previous
chapter came to light at Bouri in 1999. Binford et al were
arguing, rather, that later-developing, larger hominids like
Homo erectus, H. neanderthalensis and, indeed,
early members of sapiens itself, could not have been
effective hunters.
Not everyone bought the “early humans didn’t
hunt” theory. “I suspect,” Richard Leakey
wrote in 1994, “that the recent intellectual revolution
in archeology has gone too far, as often happens in science.
The rejection of hunting in early Homo has been too
assiduous.”
* * *
If it’s true that humans only became effective hunters
very recently, i.e. within in the last fifty thousand years,
then how do paleoanthropologists explain the fact that animal
bones clearly butchered by human-made tools are already present
in 2.5-million-year-old deposits? Hominids got hold of such
bones, the “humans didn’t hunt until recently”
school explained, by scavenging. The adherents of that school
sold scavenging as an “objective” or “dispassionate”
explanation for early hominid meat-eating. Initially, they
explained, we’d resisted the idea that hominids had
scavenged to feed themselves, because scavenging was an “undignified”
and “unromantic” pursuit. Now, however, (their
explanation continued) we were getting out of denial and accepting
the “unflattering” notion that our ancestors had
lived on the remains of hunter-predators’ kills.
The idea that it’s “unflattering” to be
thought of as a scavenger rests, however, on the erroneous
assumption that scavenging is a less demanding way
of getting hold of meat than hunting. That misconception is
related to the classic 1950s myth that scavengers like hyenas
and jackals are “cowardly,” “skulking”
creatures, while “hunters” like lions are “noble”
and “brave.” There’s no denying that the
spotted hyena, Crocuta crocuta is well-equipped for
scavenging – it’s able, as Richard Estes informed
us at the beginning of this chapter, to chew and digest bones
that are not chewable or digestible by other carnivores. Crocuta
is, however, just as eager to get hold of fresh, meaty
carcasses as lions or leopards are, and just as able to satisfy
that desire by hunting. Single spotted hyenas kill fully-grown
wildebeest bulls, and groups of them successfully take on
even larger prey.
Africa’s wild savannas are divided among perpetually-warring
clans of these fierce, aggressive animals. Competition for
food between, and within, spotted-hyena clans is ferocious.
Each clan patrols the boundaries of its “property”
regularly, using force whenever necessary to assert its exclusive
rights to occupy that territory. Crocuta’s
most effective “enforcers” or “soldiers”
are its females. “Females,” Estes tell us, “not
only dominate males at kills and other favored sites, but
also lead clan members on pack hunts, boundary patrols and
into battle.”
Many of those battles are with lions. When they have a substantial
numerical advantage, hyena packs can force groups of lions
– especially those unaccompanied by adult males –
to retreat. Male lions have been seen, in their turn, to single
out, pursue and kill their enemies’ big, aggressive
female leaders. It’s no exaggeration to say that wars
of varying levels of intensity are fought on a permanent basis
between groups of these two species. Because lions have the
upper hand in most direct confrontations, some lion prides
actually obtain most of the meat they eat by stealing
hyenas’ kills.
Scavenging is not, therefore, something which “noble”
animals like lions leave to “undignified” creatures
like hyenas or hominids. It is, in fact, often a more desirable
option than hunting, and the privilege, accordingly, of the
most powerful carnivores. “Carnivores scavenge when
they can,” Pat Shipman tells us, “and hunt when
they must.” Why should a predator expend its energy
on the chancy business of chasing and killing prey, when it
can take an already-killed animal from a competitor who will
retreat when challenged? Lions and hyenas rob leopards and
cheetahs (and each other) at every opportunity. Always on
the lookout for “easy meat,” these two top predators
pay close attention to the movements of vultures, using those
birds as “eyes in the sky” to get early information
about kills made in their territory.
This vigilance means that the remains of animals which meet
their death in a wilderness ecology will usually be located
and devoured quickly. It’s silly to suggest,
therefore, as Ian Tattersall does in his Becoming Human,
that the tool-marked bones found in association with some
Neanderthal living areas could have been obtained from “older
individuals who might have died naturally.” In wilderness
ecologies, “dying naturally” almost invariably
means being dispatched by a predator or predators, and then
being consumed without delay by your killer(s), and an eager
retinue of mammalian, avian, and invertebrate scavengers.
It simply isn’t possible that bodies of animals who
had died of old age would have been available frequently enough
to supply hominids with a regular source of meat. There’s
no question that Neanderthals would occasionally have chanced
upon seriously-injured animals like the buffalo my friends
and I came upon in the Okavango, or found helpless young deer.
In the overwhelming majority of cases they would, however,
have had to hunt the animals whose meat they wanted to eat,
or get to a kill quickly, and drive its “owners”
away with a phalanx of spears and a hail of stones before
the latter had a chance to consume too much of their property.
* * *
Stealing a predator’s kill before its “owner”
has eaten enough of it to satisfy its own needs, is referred
to, for obvious reasons, as “aggressive” or “confrontational”
scavenging. Aggressive scavenging can shade off into the “aggressive
begging” we see when a group of spotted hyenas harasses
lions who’ve eaten their fill, until the latter finally
leave the kill to get away from the annoyance.
At the opposite end of the scavenging continuum, we find
“passive scavenging.” That’s where the food-seeker
waits for the hunters and/or aggressive scavengers to go away,
and then walks into the kill-site unopposed, to look for whatever
edible scraps they may have left. This, Lewis Binford thought,
was the only kind of scavenging early humans indulged in.
He acknowledged that carcasses utilized in this way would
not usually have any meat left on them. “The major,
or in many cases, the only usable or edible parts consisted,”
Binford wrote, “of bone marrow.”
The hominid-butchered bone-fragments discovered at Bouri
confirm that early hominids did break open bones to get at
their marrow, but the cutmarks found on many if not most of
the Bouri bones or bone-fragments prove that the bones in
question were defleshed before they were smashed
open. The position of the cuts on one of them shows, in addition,
that it was “disarticulated,” i.e. cut off from
a larger fragment or from a whole carcass.
The only kind of “nonconfrontational” scavenging
which might have allowed our species regular access to flesh-covered
carcasses, is (as I see it) the theft of the gazelle-sized
carcasses which leopards often store in trees. Given the fact
that australopithecines were agile trees-climbers, I imagine
that “larcenous” scavenging of this kind must
have taken place relatively often. That possibility does not,
however, solve the mystery of how hominids living in the Pliocene
and early Pleistocene came into possession of the flesh-covered
limbs of mammals larger than gazelles. The medium-sized alcelaphine,
the three-toed horse, and the “large bovid” whose
remains were butchered by Bouri hominids, are outside the
size-range of animals normally killed by leopards, and the
human-butchered buffaloes, hippos and elephants found at the
early-Pleistocene sites we’ll discuss later, are of
course, clearly so.
Shortly after the Bouri bones were discovered, further sets
of cutmarked bones were discovered in 2.6 - 2.3 million-year-old
layers about sixty miles away, at a locality called Gona.
Manuel Domínguez-Rodrigo et al. spell out some of the
implications of these finds in the following abstract of a
contribution to a Paleoanthropological Society conference
published in April, 2003:
Newly discovered archaeological sites at
Gona (Ethiopia) preserve both stone and faunal remains.
These sites have also yielded the largest sample of cutmarked
bones known from the time interval 2.6 - 2.3 million years
ago (Ma). Most of the cutmarks on the Gona fauna possess
obvious macroscopic (e.g. deep, V-shaped cross-sections)
and microscopic (e.g. internal microstriations, Herzinian
cones, shoulder effects) features, that allow us to identify
them confidently as instances of tool-imparted damage caused
by hominid butchery. In addition, the anatomical placement
of the cutmarks on several of the recovered bone specimens
suggests that Gona hominids eviscerated carcasses, and defleshed
fully muscled upper and intermediate limb bones of ungulates
– activity which further suggest hominids gained early
access to large animal carcasses. These observations support
the hypothesis that the earliest stone artifacts functioned
primarily as butchery tools and also imply that hunting
and/or aggressive scavenging of large ungulate carcasses
may have been part of the behavioral repertoire of hominids
by c. 2.6 - 2.5 Ma, although a larger sample of cutmarked
bone specimens is necessary to support the latter inference.
The cautious note on which this abstract closes is restricted,
of course, to the 2.6 to 2.3 million-year-ago time-frame –
we’ve accumulated so much evidence of hominid butchery
of large animals of the Late Pliocene and early Pleistocene,
and accumulated it, moreover, in so many different parts of
Africa, that such butchery can no longer be regarded as a
fluky or aberrant occurrence. In addition to the Pliocene
sites we’ve just been talking about, cutmarked bones
have been found at early-Pleistocene sites including Kenya’s
Koobi Fora region, Olduvai Gorge in Tanzania, and South Africa’s
Sterkfontein Valley. The cumulative message sent to us by
these finds, is that the hominids of that time were somehow
getting access – on a fairly regular basis – to
animal carcasses that had flesh on their bones. As I’ve
already argued, it doesn’t ring true that those hominids
would, in the normal course of events, have gained possession
of flesh-covered bones or carcasses by passive scavenging.
Regular access to valuable resources of that kind could, in
my view, only have been obtained by hunting or by confronting
other meat-eaters.
When we consider the “other meat-eaters” that
existed in Late Pliocene-Early Pleistocene Africa, confrontational
scavenging begins, however, to look like an even more unlikely
alternative than hunting. In addition to lions, leopards and
cheetahs, the Africa of that time was inhabited by three species
of “machairodont” cat: the scimitar-tooth Homotherium,
the “classic” sabertooth Megantereon,
and the dirk-tooth Dinofelis. Early-Pleistocene Africa
was, as we’ve seen, also inhabited by the enormous Pachycrocuta
hyena.
It’s difficult to see how the australopithecine hominids
who butchered the Bouri and Gona bones could have defended
their kills against – let alone stolen meat from –
a beast like Pachycrocuta. This giant hyena lived
throughout Africa up until about 1.4 million years ago (and
stayed in existence a good half-million years longer outside
that continent.) It occupied an immense stretch of territory
between Spain, South Africa and China, and occurred, as one
might expect from such a widely-spread genus, in a variety
of forms. Paleontologists distinguish P. pyrenica, P.
bellax, P. robusta and P. brevirostrus. Pachycrocuta’s
largest forms were as big as a present-day lion, and the structure
of its teeth and jaws shows that it was, like its close relative
the still-existing spotted-hyena Crocuta, specially
adapted to the business of crushing and eating bones.
Just as we were tempted, therefore, in the late Twentieth
Century, to say “early hominids must have scavenged
because they couldn’t possibly have hunted,” reflection
on the formidable size and power of Pachycrocuta,
and on the big cats which existed along with it, could drive
us to the opposite conclusion: that the hominids of 2.5 million
years ago must have obtained the carcasses they butchered
by hunting, because they couldn’t possibly have scavenged!
I’ll argue presently that the late-Pliocene australopithecines
who processed the cut-marked bones found and Bouri and Gona
did obtain many or most of the carcasses they butchered by
hunting. We can surmise that the hominid hunters of 2.6 million
years ago, might only have been able to defend those carcasses
against relatively manageable challengers such as cursorial,
striped and brown hyenas, surrendering them, perhaps, only
to more frightening ones like Pachycrocuta hyenas
and big cats. Gaining the ability to drive off even some
kinds of predator-scavengers, would have meant, however, that
they had also gained the ability to steal meat from those
species. It seems reasonable to assume, therefore, that late-Pliocene
australopithecines of the kind that butchered the bones found
at Bouri and Gona, might have augmented their hunting activities
with both larcenous and confrontational scavenging.
* * *
Adjectives like “crude” and “simple”
aren’t used as frequently as they used to be to describe
Oldowan cutting flakes, since we’ve become aware of
how much knowledge and skill was required to make those tools.
Their makers would have to had to know, firstly, how to identify
the “isotropic” rocks required for their manufacture
– i.e. those that split in any direction, rather than
along a single preferred plane like slate. Pliocene tool-makers
must, therefore, have been able to identify high-quality tool-making
materials like obsidian, flint and chert, and passable ones
like fine-grained quartzite. They would, it seems, assay the
qualities of likely-looking rocks in the same way a modern
geologist does – by hitting them with a hammer (except
of course that their hammers would have been stones). “You
could tell,” relates Craig Feibel, a geologist-anthropologist
who investigated the 2.3 million-year-old Lokalalei 2C tool-making
site west of Lake Turkana, “that they would pick up
a cobble that was coarse grained, hit it a couple of times,
and see it wasn’t good. Then they would pick up a fine-grained
rock, see it was the right quality, and keep chipping, and
knock thirty flakes off a single core.”
A considerable degree of technical skill would have been
required to produce those flakes. By teaching himself to reproduce
tools of the Oldowan pattern, Nick Toth has found out that
their manufacture involves a great deal more that just banging
two rocks together. You have to find a “shelf”
forming an “acute” or less-that-90 degree angle
in the rock you’ve selected for flaking – or make
one – and then deliver an accurate blow about a half
an inch from its edge with your “hammerstone,”
making sure that the force of your blow travels through the
right area of the “core” rock to detach a usable
flake.
The late-Pliocene hunter-foragers we’ve been talking
about didn’t sit around at a home base making the tools
which they would take with them on tomorrow’s or next
week’s hunting expedition. Later hominids often did
things that way, but Oldowan tools were typically made at
the butchery site where they were used. We know this because
flakes produced in the course of the manufacturing process
are liberally scattered around many kill sites, and because
“manuports” – raw material in the form of
non-local rocks – are also sometimes found at such sites.
We know it, too, because archeologists have repeatedly managed
to re-assemble the original cobbles from which flakes were
struck, at the places where those tools were used.
The fact that the butchers of the late Pliocene made their
“meat cutters” at the places where they used them,
shouldn’t lead us to believe, however, that they would
only have sought out and collected the raw materials needed
to make those cutters after a carcass had been secured.
Many or most butchery-sites would have been situated miles
away from outcrops of workable rock. Gona is, as I’ve
mentioned, the nearest source of tool-making rock to Bouri
where the carcass-processing we’ve been talking about
was done. If the hominids who gained control of the Bouri
carcasses had to walk the sixty miles to Gona to fetch tool-making
rocks after they’d secured the carcasses in
question, and then walk and sixty miles back, the meat would,
of course, have been long gone by the time they got back.
It’s generally accepted, therefore, that the Oldowan
tool-makers of the late Pliocene and early Pleistocene would,
in many cases, have taken their tool-making cobbles with them
on their hunting-foraging expeditions, carrying them as unopened
packages of fresh blades, so to speak, in anticipation of
securing a carcass that would require butchery.
How did those tool-makers carry the cobbles they
took with them on those expeditions? Chimpanzees have been
seen to carry the rock “hammers” they use for
opening certain kinds of nuts for a little over 500 meters,
but the hominid toolmakers of the Pliocene carried their “unopened
packages of blades” for many miles. It’s highly
unlikely that they would have carried those rocks in their
hands. One of their hands would have been employed, as I’ll
argue presently, in carrying a spear, club or staff. My own
experience of walking in the African savanna tells me that
the other would have been in constant use, steadying their
passage over a rocky outcrop here, and gingerly pushing a
thorny branch out of their way there. It would also have been
used to pick the berries and other fruits they would have
been passing, to shade their eyes, to feel the temperature
of fresh dung, and to chase off flies. That “free”
hand might have been used for signaling, too, at times when
it was critical to maintain silence, and to work with the
other hand in the manipulation of weapons.
It’s just not realistic, in short, to assume that the
late Pliocene hunter-foragers we’ve been talking about
would have carried their tool-making rocks in their hands.
Could they have suspended them from their shoulders or necks
in animal-skin slings or bags? Hominids may well have “invented”
bags of that kind for gathering vegetable foods in the late
Pliocene, but hunting and aggressive scavenging would have
involved trotting, running at full tilt, and executing all
the demanding body-movements that would have been part of
the business of bluff, attack, evasion and retreat. A heavy,
loose object hanging from the neck or shoulder would interfere
with those kinds of movements. It seems likely to me, therefore,
that the Oldowan tool-makers may have bound their rock-carrying
“bags” snugly against their bodies in a rough
kind of “fanny pack.” Tying the simple knots required
for this kind of device need not, in my view, have been beyond
the capabilities of a hominid who’d acquired the demanding
skills required to create stone cutting-tools.
* * *
Now for the matter of weapons. I’ve argued that the
hominids who butchered the cutmarked bones found at Gona,
Bouri and elsewhere must have obtained the majority those
bones either by hunting or by confrontational scavenging.
Since late-Pliocene hominids weren’t nearly as big or
as powerful as Africa’s largest predators, and since
they weren’t equipped with the kind of teeth or claws
that those carnivores possess, they could not have hunted
animals as big as, or bigger than themselves (or have confronted
the big meat-eaters which would have been competing with them)
without hand-held weapons like wooden staffs, clubs, or spears,
or “distance weapons” like thrown rocks.
Their spears would not have been tipped by stone
points. The development of composite weapons of that kind
lay more than a million years into the future. Their spear-points
were made by simply sharpening wooden shafts. Oldowan cutting-tools
weren’t only used for butchery: they were also used
for working wood. A 1981 Nature article by Lawrence
Keeley and Nicholas Toth reports that the authors established
the existence of microscopically distinct wear polishes on
products of the so-called Karari Industry, a more recent variant
of the Oldowan Industrial Complex (the implements in question
date from a about 1.5 million years ago). Nine of the fifty-four
implements examined showed wear traces. On three of those
nine, the traces were of the same kind as those the authors
produced experimentally by working wood with stone tools they
had made themselves. One of the three wood-marked tools displayed
the kind of crescent-shaped damage scars that the authors
produced experimentally by using stone flakes as saws.
It seems likely, therefore, that stone cutting-tools might
have been used from their inception to shape spears, and sharpen
their wooden points. Hominids may, in fact, have been sharpening
sticks and bones by rubbing them against abrasive rock before
the advent of stone cutting-tools. Adrienne Zihlmann has underlined
the importance that the gathering, transportation and sharing
of plant foods must have had for the development of hominid
technology. It’s likely, in this view of things, that
digging sticks were used before the advent of manufactured
stone tools, and the technological distance between a digging
stick and a spear is a short one.
I’ll have more to say about the development of tools
and weapons presently. Let’s step back, first, however,
and take a look at the hominids who processed the 2.5-year-old
cutmarked bones that we’ve been talking about. If they’re
Homo habilis, or something like that species, then
the tops of their heads are probably round, like those of
chimps or humans. If they’re Australopithecus garhi,
then humps of muscle and fat on top of their heads might have
given them a gorilla-like look. (Some of Garhi’s
big chewing muscles were, like those of gorillas, anchored
to a bony crest running across the top of its skull.) The
bodies of such hominids probably look more human-like than
their heads, but their forearms remain disconcertingly long
and ape-like. Garhi’s thighs are, however,
probably longer than those of those of a typical australopithecine.
Garhi is, for this reason, taller than the other
hominids of that time, but still shorter than modern humans.
If we could travel back in time, and habituate a group of
late-Pliocene hominids to ourselves the way Diane Fossey and
Jane Goodall did with gorilla and chimp groups, we’d
probably come to regard some of them with the affection and
respect Fossey felt for Digit, and Goodall had for Flo. We’d
like and respect them, though, as fellow-creatures rather
than fellow-humans. The sexual and emotional parts of our
minds would probably insist loudly that beings like Australopithecus
garhi and “Homo” habilis are animals.
Chimps, gorillas and orangutans are, however, already disconcertingly
human-like animals, so the late australopithecines would,
no doubt, have been even more disconcerting in this
regard.
Imagine such “animals,” walking upright like
humans through the Pliocene bushveld. About a million years
will go by before the family of which they are members will
learn to use fire, but these beings do not exist in a state
of technological naivety. They could be carrying digging,
fruit-hooking and hunting sticks, and one or more of them
might, as I’ve suggested, be wearing pouches containing
raw materials for the manufacture of stone tools and, perhaps,
a favorite hammerstone. Those pouches might also contain non-utilitarian
but “interesting” objects like shells or stones
that caught the eye of their finder. A remarkable jasperite
manuport from Makapansgat in South Africa, brought to that
site by a hominid between 2.5 and 3 million years ago, has
two holes representing eyes, and another representing a mouth.
These features weren’t carved into that flat, oval stone
– the stone’s resemblance to a hominid face is
accidental, but almost certainly the reason why it was noticed
and picked up.
Pouches carried by these upright-walking “animals,”
might contain food and even water stored in naturally-formed
containers like hard-shelled fruits or animal bladders. Infants,
too, might be tied against, or suspended from, their mothers’
bodies in animal-skin holders.
* * *
It’s central to Darwin and Wallace’s theory of
evolution by natural selection that the bodies and behaviors
of living beings change relatively gradually, over thousands
of generations. The fact that such change takes place at a
slow rate, does not mean, however, (as Richard Dawkins
explained with such persuasive clarity in his Blind Watchmaker)
that it takes place at a constant rate. It probably
proceeds, on the contrary, by what Darwin himself described
as “slow and interrupted steps.”
Let’s consider, for a moment, the “slow and interrupted
steps” which might have led from the killing and eating
of squirrels and infant monkeys by our ancestors, to the hunting
and butchering of large antelopes. It’s probable, as
we’ve seen, that those ancestors started hunting before
they started walking upright. At this stage they would, like
present-day chimps, have been killing their prey without hunting
weapons, “butchering” it – i.e. tearing
it apart – with their hands and their teeth.
Chimps can, as we’ve seen, catch, kill and dismember
animals the size of a 25 lb. colobus monkey with their bare
hands. It’s quite possible, therefore, that hominids
may also have been able to kill and butcher animals of this
size without using weapons or tools. It’s less likely,
but still possible, that they could have used their bare hands
to catch, kill and dismember animals as big as the 50-70 lb
ground-dwelling Paracolobus monkeys which lived in
the late Pliocene and early Pleistocene. It begins to look
highly unlikely, though, that they could have killed and dismembered
100 lb. animals like, say, gerenuk antelopes in this way.
By the time hominids were eating the meat of antelopes weighing
150 lb or more, we know for sure (from the archeological evidence
we’ve been discussing in this and the previous chapter)
that they were butchering those animals with stone blades
and scrapers. If they gained control of many of those big
antelopes by either killing them or stealing them from their
killers, – an unavoidable conclusion in my view –
then it’s a practical certainty that they used weapons
for both those purposes.
* * *
The development of weapons was, in Charles Darwin’s
opinion, intimately linked with our species’ bipedality.
“The hands and arms,” he wrote in his Descent
of Man, “could hardly have become perfect enough
to have manufactured weapons, or to have hurled stones and
spears with true aim, as long as they were habitually used
for supporting the whole weight of the body...”
“Darwin was arguing,” Richard Leakey comments
on this passage, “that the evolution of our unusual
mode of locomotion was directly linked to the manufacture
of stone weapons.” Since manufactured stone implements
only came into use about 2.5 million years ago, Leakey reasoned,
and humans have been walking on two legs since at least six
million years ago, the two phenomena could not have been related.
“Whatever the evolutionary force that produced the bipedal
ape,” Leakey concluded, “it was not linked with
the ability to make and use tools.”
It’s true that Darwin linked the development of bipedality
with the manufacture of weapons, but he didn’t, as Leakey
suggested he did, link it to the manufacture of stone weapons.
The modification of stone to make tools or weapons must, (as
Darwin himself pointed out in The Descent) have been
preceded by a long period during which unmodified stones were
used for those purposes. Contemporary observations that chimpanzees
sometimes throw stones at competitors and predators, and that
some chimps use stones to break open nuts, underscores the
reasonableness – and, in fact, the obviousness
– of this commonsense assumption.
The use of sticks by chimps to expel birds and mammals from
in holes in trees, to dig honey out of bees’ nests,
and to intimidate competitors and predators also adds credibility
to the idea that hominids must have used sticks as tools and
weapons for a very long period of time before they learned
to make stone tools.
In a very real sense chimpanzees already “manufacture”
tools – they pluck, strip and trim the twigs they use
for termite “fishing,” prepare the branches that
they use to hook fruit-bearing branches into reach, and process
the leaf-masses that they use to sponge water out of hollow
trees by chewing them. The same logic that tells us that the
chimp and human families probably inherited their meat-eating
ways from their common ancestor, suggests that that the two
families derived their tool-using abilities from the same
source. It’s by no means unlikely, therefore, that hominids
were using a variety of objects as tools and/or “weapons”
(in both modified and unmodified states) before they started
walking upright.
Darwin’s guess that the development of “weapons”
and upright walking could have stimulated each other’s
development remains, therefore, in my view, a good one.
Darwin believed, in addition, that the positive feedback
loop which linked upright walking and the use of implements,
included the development of our species’ extraordinary
level of intelligence. Richard Dawkins questions that linkage.
“...[T]his is a rare instance,” he argues, “where
Darwin’s tentative guess has turned out wrong. The fossils
give a satisfyingly clear and decisive answer. Bipedality
came first, and its evolution was more or less complete before
the brain started to swell.”
The fact that the Pliocene butchers of the middle Awash had
small brains need not, however, invalidate Darwin’s
hypothesis that the development of tool-use and bipedalism
were linked to an increase in hominid intelligence. Dawkins’
argument against it rests on the assumption that there’s
a strict correlation between a primate’s brain-size
and its intelligence: if australopithecines had chimpanzee-sized
brains, then their mental capacities must also have been on
more or less the same level as that of a chimpanzee. Hominids
could not, ergo, have become smarter than chimps until their
brains got bigger, and, since that only happened millions
of years after they learned to walk upright, the “beyond
chimpanzee” level of intelligence could not have developed
in concert with the development of upright walking (and tool-making)
as Darwin thought it might have.
It’s clear, though, that the small-brained australopithecine
butchers of Gona and Bouri made stone cutting-flakes, gained
control of the body-parts of large ungulates, and used their
cutters to disarticulate and deflesh those body-parts. These
achievements are very far beyond the intellectual abilities
of chimpanzees. The intelligence of at least one hominid species
had, therefore, already exceeded that of chimpanzees to a
very significant extent while the size of its brain was still
close to that of a chimp. The superior intelligence which
characterizes our species may well have gotten its start,
therefore – as Darwin suspected it did – by stimulating,
and being stimulated by, our species’ development of
bipedality and its use of tools and weapons.
CHAPTER 11–
A
radically different kind of faculty
