The following is taken from Rick Potts' Humanity's Descent:
Technology. The oldest human technology we know of is captured in stones of lava and quartz and is as simple as one could imagine. Hitting one rock on the edge of another makes a sliver of stone fly off. Its acute edge is sufficiently sharp to cut with. The larger piece of rock, or core, has a scar whose end is also useful for cutting and provides a platform for knocking off more sharp flakes. As this basic action is repeated, a core begins to exhibit multiple scars, as if a pattern were being made.
The hammerstone eventually shows signs of battering. Other rocks also reveal indentations and crushing. In the oldest known technology, Oldowan toolmaking, rocks were made sharp by percussion flaking, or were dulled and shattered by direct use. Superb collections of this oldest lithic technology have been studied for over thirty years, and the plethora of observations boils down to the question, What did stone toolmaking signify to the hominids who first tried it?
We've already seen one ramification: Stone toolmakers could start the process of digestionchopping, slicing, and grindingwithout being limited to the mouth's dental machinery. Compared to wooden implements peeled and broken by hand, tools could open even the toughest containers of food. And as the range of accessible foods grew larger, the same chipped rocks opened new channels to the diverse mosaic of savanna resources. Tooth-mimicking was the centerpiece of the first stone technology.
Rocks are heavy and have no caloric or nutritional value, so the time and energy spent finding suitable stones added a sizeable burden to the process of getting food. The new teeth were made a regular part of the food search only by bringing the stones and the foods together. Oldowan toolmakers solved this problem by moving resources from one place to another. The accumulation of stone tools on the landscape greatly extended the simple toolmaking practices known more widely among the primates.
Certain groups of chimpanzees face a similar problem today. In parts of West Africa, chimpanzees visit oil-palm trees to harvest edible nuts. In one study area, the chimps sometimes use locally available rocks as hammers and anvils to crack the tough outer casings. At certain trees they may require only a single stone in order to break nutshells against an exposed, anvillike root.
The chimps abandon these rocks at the bases of trees, revisiting and reusing them until nuts are ripe at a different tree. Based on studies by Christoph and Helwig Boesch, chimpanzees develop a mental map of where nut trees are located. They also remember where a stone hammer was last used. These places are visited, and if the hammer is still there, the returning chimp carries it to the next target tree, typically within one hundred meters. When fellow chimps have already taken the rocks to a different tree, the disappointed chimp continues to scour the places where nut-cracking stones might have been left, until one is found.
The chimpanzee nut-crackers' solution to the issue of getting the tool and the food together is to bring rocks directly to the food source. Nut trees do not change their location, so the hammers and the sources of food overlap precisely.
But what about the most ancient sites in the eastern part of the continent, where the only apes present were the bipedal variety? Only a few such sites, more than 2 million years old, have been excavated. The Gona sites of Hadar, Ethiopia, nearly 2.6 million years, are among the oldest known. Chipped stone tools have been found in and adjacent to the ancient streambeds. At the 2.4-million-year site of Lokalelei, West Turkana, early toolmakers used lava cobbles, some with very poor flaking qualities, retrieved from the streams that flowed near the site. It may be that as stone tools were first brought into the foraging process, they were used only in the immediate vicinity of the rock sources.
By about 2 million years ago, hominid toolmakers demonstrated a different solution to the problem of transport, seen at a series of wellstudied sites excavated by Mary Leakey in the Olduvai Gorge. Various kinds of chipped implements and raw material, carried from places as far as one to six miles away, were discovered at the sites. Accumulations of animal bones, including fractured limbs and other body parts taken from animals that had died some distance away, were also found there. Cut marks made by stone tools, demonstrated in 1981 by Pat Shipman, Henry Bunn, and myself, linked the two types of transported remains. Over a period of time, the toolmakers had broken and deposited the bones in the places where rocks had been carried. The oldest sites that give evidence of extensive stone transport, numerous parts of animals, and definite cut marks on bones are about 1.9 million years old.
The transport of acquired items was a turning point in the behavior of early toolmakers. At least two kinds of resources were involved stone tools and foods that needed to be processed. Both were taken from their sources on the landscape and brought to common ground. The connection had been made at Olduvai, and probably earlier. Once the link was established, any movable item could be taken to a place where suitable rocks could be found. A stone flake, a core, and a hammerstone were surely carried around. But the advantage of tools was having them available whenever required. The solution was to drop lava cobbles and slabs of quartzite in various parts of the foraging range. It merely required the toolmakers to recall the places where these rocks had been temporarily discarded.
Chimpanzee nut-crackers suggest how this system got started. A stone or two was deposited at a favored tree. Perhaps a few other tools and rocks were left at a carcass, near water, or next to another favored resource. Over time, toolmakers were repeatedly attracted to these places. If food that required the use of tools was found, it meant a visit to a remembered location. Wherever stones were dropped, chances were raised that hominids would return. More visits meant more stones from distant places, the basic recipe for making an archeological site. This is one scenario that fits nicely with the archeological evidence from Olduvai. But however it was actually carried out, the dual transport of resources was a key marker in our ecological genesis that amplified the simple act of making tools out of rock.
Trash. By acquiring and carrying things to certain spots, early humans created zones of waste and clutters of objects both useful and useless. Besides giving jobs to archeologists, this behavior marked the beginning of a trait peculiar to human beings, which Glynn Isaac, who stimulated tremendous interest in the archeology of human origin, once referred to as the start of the human proclivity for making garbage.
The places visited again and again by Oldowan toolmakers were the first waste disposal sites, and they have stayed around for a couple of million yearswhich may give us pause about our artifacts and current pilings of refuse. Hitting rocks together and making clusters of debris formed the tiny apex of the enormous taproot that nourishes our deep propensity to amass wastes.
Any innovation has its costs. What was it about toolmaking that financed its inherent costs? What advantages urged certain groups of hominids to seek heavy rocks and cart them from place to place?
If these primordial roots of human energy use were a Pandora's box, the box had to be cracked, sliced, and chopped in order to open it. And simple things emanated out of this boxseeds from a hard fruit, marrow from a large bone, pith from a tough stem. Simple stones wielded in a simple manner allowed a wider range of food sources than ever before.
Startling new forms of technology obtain a foothold in modern society when they reap new gains in energy or assist in securing some vital resource. These patterns of advantage may have been established by the oldest stone flaking. But we cannot yet compute the energy advantages of ancient toolmaking or be sure of the new sources of food that could be exploited. Because animal bones are readily preserved as fossils, and because of entrenched biases in our thinking, anthropologists often presume that meat was the first dietary breakthrough. According to this view, animals provided a new source of nutrition, underwriting the earliest toolmaking attempts. At present, however, there is no compelling reason to overlook the broad range of plant foods that could also have been reached by flashing those external lithic teeth.
Archeologists Nicholas Toth and Lawrence
Keeley have searched for microscopic polish on the edges of stone tools.
The only pieces to show microwear were small, sharp-edged flakes. The original
materials on which these flakes were used included wood, soft plants (stems
or grass), and meat. Even though their study focused on implements around
1.6 million years oldabout a million years after the advent of stone flakingToth
and Keeley have shown that access to meat was not necessarily the only motive
for chipping a sharp stone.
Oldowan toolmakers eventually availed themselves of a strange new optionthe nutrition locked up in large animals. Literally thousands of bone fragments, representing dozens of individual animals, have been unearthed in even small excavations. The sizes of the animals these represent are considerably larger than the occasional monkey or tiny antelope eaten by a chimpanzee or a baboon. While all higher primates eat an eclectic diet, none except human beings regularly seeks out animals the size of impalas, gnus, or even larger creatures. By the 2 million-year mark, human toolmakers had raided a totally new source of energy and nutrition, once the exclusive domain of large carnivores.
It is now widely accepted that this breakthrough was conducted in part by scavenging animals already dead. According to studies by archeologist Rob Blumenschine, marrow and meat can readily be scavenged in modern habitats of East Africa at certain times of year. While nothing rules out the idea that hominids occasionally dispatched an animal by hand or modest projectile, systematic hunting of large animals, clearly signaled at much later sites, is not apparent in the archeological record as far back as Oldowan toolmaking.
We can only imagine the first dashes into the realm of large predators and scavengers. Perhaps those initial eventsstolen opportunities for innards and beast tartarewere spread out over thousands of years, an individual or a group here and there braving a hyena, a lion, or a sabertooth.
Spotting an unattended carcass, a biped seizes the moment, smallteeth ripping at flesh already opened the night before, perhaps by a sharp-toothed cat. Hunger is sated by the moist, chewy tissues of a creature larger than any she had dared consider before. In that instant, neither the size of the animal nor the future importance of this activity means a thing. It's just that this large, unmoving, smelly thing has impenetrable bones layered with nutrition. You see these things standing together in the distance; now here is one on the ground, and it offers something to eat.
In this situation, the advantage of having a sharp sliver of lava, capable of slicing thick hide, is pretty obvious. It takes dozens of such slivers to get much meat from a large animal, and to extract nutritious marrow by cracking the bones demands a far heavier stone. A carcass may offer more than food; hide and ligaments also have uses in otheraspects of life. Once again, bringing carcass parts and tools together in the same place at the same time seems crucial. Death sites of animals are far less predictable than plant- food sources. So knowing where stone tools had previously been dropped becomes an important fact of life.
When tense conflict occurs between large carnivores, it is usually around the death sites of their prey. The tensions translate into a kind of sharp-toothed pecking order as hungry scavengers wait their turn. Even in the face of such orderly conflict, dangerous motivations seethe around any carcass encountered by more than one meat eater. With the exception of vultures and perhaps the cheetah, all such scavengers were potential predators of the smallish toolmakers.
A surprising finding occurred some years back as I inspected several thousand fossilized animal bones unearthed from the oldest prehistoric sites of Olduvai Gorge, approximately 1.8 million years old. The diversity of animals, concentration of remains, and mix of skeletal parts made it quite evident that hominids had accumulated these bones some distance away from the original places where the animals had died. Long ago, somethingor someonehad transferred bones from many different carcasses to specific spots on the landscape. At some sites, cut marks and the abundance of tools implied that human toolmakers were responsible. At others, tools were largely absent, and the gnaw marks on the bones matched those engraved by bone-eating hyenas.
A remarkable pattern emerged as I perused the sites where stone tools and fossilized bones coincided. Wherever hominids were active, the carnivores were there too. Large and small carnivores left distinctive glyphs in the same bony accumulations where toolmakers registered theirown telltale e marks. Both were drawn to the attached meat and marrow within the bones. These places were not the original kill sites, so scavengers must have followed the scent to the very places where hominids left their vital new dentures. This led me and a growing number of other researchers to believe that these sites were simple foodprocessing areas, lacking the social complexity of a modern home base. The benefits of fire, the safety of the family, and the swirling interactions of social life centered at the home were yet to come.
Still, these early toolmakers held in their hands a seed of no small destiny. They took one kind of object and, by transforming it, could open new sources of energy for their use. On two legs they initiated the transport of resources, and with no eye on future elaborations, they left behind the oldest piles of decayed and discarded artifacts.
We have yet to explore the environments in which these new facets of the human enterprise evolved. Since any novel behavior depends on surrounding conditions, we may wonder about the habitats in stone toolmaking arose, and why this odd experiment by early humans endured. Toolmaking, transport, and trash collecting were not conceived for the sake of our present dominion. They were born in relation to environments of that ancient time, environments of uncertainty, prone to change.