The Evolution of a toolkit

There is a consensus that by about 300,000 years ago, there is a distinct shift in stone tool technology that is recognized by scientists as a shift from the late Acheulean to the Middle Stone Age (MSA). The MSA has flakes that are made on prepared cores and shows a shift away from hand axes as the primary tool type. A prepared core is a core where the core is carefully shaped so that it is ready, or prepared, to strike off a flake of a particular shape. One of the classic shapes was a point, and points can be used as projectile tips, knives, scraping tools, etc.

The types of points proliferate and begin to show regional and temporal patterns. Some points are unmodified flakes that have been knocked off, with great skill, from the prepared cores. These become a common flake form around 300,000 years ago. Others are carefully shaped with repeated flaking into a biface, and some appear to have received their final shaping with a technique called pressure flaking where the flakes are pushed off in a highly controlled manner. These bifacial points become common between 110,000 to 70,000 years ago. Some are long and thin and others short and squat. Some have bases that have been modified in ways consistent with hafting. All of this suggests an intense concern with the production of projectile points and knife blades.

A second stone tool form that begins to proliferate is called blades. Blades are very common after about 110,000 years ago. Blades are flakes that are twice as long as they are wide. Many blades are also made on prepared cores, and some of these cores take on regular forms so that they can produce many blades all rather similar in shape and size. Blades are also highly variable, some being long and others short. Evolving out of blade technology is microlithic technology, and in most cases microlithic technology involves the snapping of blades into smaller pieces, and then the blunting of one edge. Ethnographic and archaeological examples show us that the blunted edge was inserted into a groove in wood or bone, glued in along with other microliths, to create projectile point or cutting edges. Overall, there is a pattern of miniaturization over time, and this has been interpreted to be directed at lightening the weight of the projectile. The earliest evidence for microliths comes from a field site at Pinnacle Point, South Africa, dated to about 72,000 years ago.

Heated blade cores dated to 65,000 years ago discovered at Klipdrift Shelter, South Africa, showing how pieces were flaked off to form a single blade (left), variety of flaked blades (right)
Image credit

Points take a dramatic turn around 70,000 years ago when in South Africa hominins begin to make them on bone. Bone points require careful grinding and polishing, and based on ethnographic evidence, they are commonly combined with blades into very effective projectiles. Bone tools appear in other classes, and the earliest now known come from North Africa. This expansion of raw material to bone is paralleled by an expansion of new stone raw materials and an increasing concern with raw material quality. Raw materials are extracted from longer distances, often 50 kilometers, or even up to 200 kilometers away. Raw materials are subjected to a new form of modification called heat treatment. In fact, the oldest evidence in the world for heat treatment, what we can think of as the first raw material pyrotechnology, comes from the field site of Pinnacle Point dated to around 162,000 years ago.

A general pattern is that over time these stone tool forms get smaller and smaller, and this is thought to represent a concern with lightening the weight to increase the distance of a cast projectile. Some scientists think that when these points, once they reach the small size of ethnographically documented atlatl and bow and arrow points, signal that this technology had appeared. This is around 70,000 years ago.

What was an MSA hominin society like?

There is consensus that by 70,000 years ago, just around the time modern human left Africa, all the characteristics typical of modern hunter-gatherers were present. They were cognitively modern. They had that special form of social learning unique to modern humans. And they had an evolved proclivity to cooperate at large scales. They had multiscale society and were organized into tribes. They had the ability to make the entire modern human hunter-gatherer toolkit and rapidly adapted it to local conditions. They had complex symbolic systems and language and institutions to organize society. In other words, they were fully modern humans. But when did this first evolve? Were hominins dating to 200,000 years ago or 100,000 years ago fully modern in the way we have defined them above? Researchers don’t have an answer for this yet, but progress for these questions is rapid, and scientists are close in on the answers.

What did these MSA hominins eat and how did they get it?

There are many sites in Africa that retain rich and well-preserved records of the foraging behavior of these early modern humans. Faunal records show us that early modern humans had flexible hunting strategies that adapted to the local fauna and seemed capable of preying on most of the large mammals. The really big animals like elephants and rhinos and giraffe are rarely preserved in the sites, but this does not mean they were not hunted—among modern hunter-gatherers the bones of these big creatures are rarely transported because they are too heavy. But at many sites the remains of a diverse array of large ungulates (hoofed animals) from buffalo to really small antelope called dik-diks are present, and they show clear patterns of cut marks and hammerstone percussion marks that leave no doubt that humans were the predator. Small animals such as hares, dune mole rats, and reptiles are sometimes present but not always. Zooarchaeologist have struggled to determine if these small animals were accumulated by humans or other predators such as owls and carnivores. This is because when they are consumed it is often the case that they are cooked whole, so cutmarks are lacking.

Organic preservation is less common, but there are some sites that have stunning preservation of plant remains even as far back as 80,000 years ago. Studies of the remains show that these early modern humans had a diverse plant diet sampling the wide range of plants that are typically present in these environments. The modern hunter-gatherer in Africa typically uses a very wide diversity of plants, and so did these early modern humans.

Many sites show outstanding examples of repeated hearth construction inside caves/rock shelters, and these hearths have the form of both single-event to multiple-event usage. The ashes of these hearths have been studied and show the combined presence of plant foods and animal remains, documenting a typical diet of meat and plants.

Interior of Pinnacle Point cave showing layers of charcoal sediments from fires. More than 50,000 years of human habitation has been uncovered at this site, including evidence of the use of fire to harden silcrete into stone tools and blades, shells and beads from gathering seafoods, and red ochre.
Image credit Donald Johanson

In an earlier section, researchers are careful to make a distinction between terrestrial hunter-gatherers and aquatic hunter-gatherers. Aquatic hunter-gatherers, as documented from the ethnographic record, are significantly different from terrestrial hunter-gatherers. Aquatic hunter-gatherers, as the name implies, get much or most of their sustenance from aquatic sources. These tend to be high-quality foods and are particularly rich in omega-3 fatty acids.

Africa has some rich coastlines and rivers and lakes, and these of course may have drawn hunter-gatherers to them. We have a rich archaeological record from these areas. Our ethnographic record in Africa for these “aquatic adaptations” is unfortunately very sparse, and almost absent. However, elsewhere in the world there is a rich record for this type of adaptation, and it paints a remarkably different picture compared to terrestrial hunter-gatherers. Aquatic hunter-gatherers, as the name implies, have broadened their diet to significant quantities of food from the water—shellfish and fish primarily. Aquatic hunter-gatherers often have very low levels of residential mobility—they may even never move and sometimes form permanent villages. The size of their bands can be large, even numbering over a hundred or hundreds of individuals. They often store food for long periods of time and have complex heavy technologies that cannot be moved easily. Importantly, they have the highest levels of intergroup conflict recorded for hunter-gatherers.

Some researchers have argued that these aquatic adaptations create an entirely new selection regime for human evolution, placing humans in a different world of social and technological behavior, and thus this would have had dramatic impacts on human evolution. In 2007, the earliest evidence for humans moving into the aquatic niche from a site was documented on the far southern tip of South Africa called Pinnacle Point. Since that discovery, and the interpretations of it, were presented, paleoanthropology has become very interested in when aquatic adaptations first arose.

A shift to the sea has many downstream impacts. Aquatic hunter-gatherers rely more on storage. For example, fish are stored for long periods through drying or special forms of controlled rotting. They have heavier technology in that it is made of more parts, more diverse raw materials, and thus is less subject to being carried around with ease. They are more sedentary and less mobile. Terrestrial hunter-gatherers tend to make many residential moves, sometimes 20 to 30 a year or more, while aquatic hunters-gatherers have reduced residential mobility, often parking themselves near where the water-based foods are concentrated and/or where they have stored the food taken from water. Their bands are often larger, and since they are more sedentary, take on the form of villages that resemble what we see with food producers. They have smaller territories, at both scales of sociality. So, the annual round of a band, and the size of the territory of the ethnolinguistic group, are smaller than terrestrial hunter-gatherers, and they often live at higher population densities. Aquatic hunter-gatherers often have higher levels of economic and social differentiation, and thus the egalitarian ethic so common among terrestrial hunter-gatherers is relaxed. They have greater levels of intergroup conflict and territoriality.

Pinnacle Point, South Africa. The bottom image is a closer view of the cave openings below the cliffs.
Image credit Erich Fisher.

An important addition to the diet

So, a shift to the sea has a big impact on all aspects of hunter-gatherer life, so much so that one researcher has called the evolution of aquatic lifeways the “fourth dietary revolution,” joining the evolution of the human predatory pattern, the broad-spectrum revolution, and the origins of food production. When did this occur? The earliest evidence is found at the field site of Pinnacle Point 13B dating to 162,000 years ago, and by 110,000 years ago in South Africa, there are several sites that document a strong commitment to aquatic lifeways. On the Atlantic coast of North Africa around 110,000 years ago, there are also several sites with evidence for coastal living. In our record for the evolution of the hunter-gatherer toolkit, South Africa regularly displays a rich record very early. This could be due to this coastal adaptation.

Written by Curtis Marean PhD

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