The Dawn of Human Culture (19 page)

spear 2

(redrawn after H. Thieme

Schöningen

1996,
Archäologisches

Korrespondenzblatt
26,

fig. 9).

05 Humanity Branches Out.r.qxd 1/29/02 5:05 PM Page 160

160

| THE DAWN OF HUMAN CULTURE

had produced a 30-centimeter (1-foot) long pointed wooden object that could be a spear tip. The other was Lehringen, Germany, where deposits that are probably about 125,000 years old had provided a complete spear from among the ribs of an elephant.

In his description of the Schöningen spears, Thieme emphasized that they were heavier towards the business end and tapered towards the back, like modern javelins. From this he argued that they were designed for throwing. Archeologist John Shea of Stony Brook University, who has investigated the evolution of projectile weapons, agrees that they were more aerodynamic than the much younger Lehringen spear, on which the center of gravity was too far back to facilitate throwing. However, he doubts that the Schöningen spears could have been thrown far or that they would have been especially lethal. “Picture yourself with an oversized toothpick trying to subdue an enraged wild bull,” he says. “These weapons may have been used for hunting—it’s hard to think of other uses for something like the Schöningen javelins—but they weren’t very effective.”

Another expert on stone-age projectile technology, biological anthropologist Steven Churchill of Duke University, doubts that the Schöningen people ever deliberately let their spears go. Churchill has scoured journals and early ethnographic reports for evidence of spear use by historic hunter-gatherers. Among 96 groups for which he found details on hunting, many employed thrusting spears, and they sometimes threw them short distances. However, he found only two groups who regularly threw spears more than a few meters. These were the aboriginal inhabitants of Melville Island, Australia, and some native Tasmanians. In both cases, the spears that the people threw were much thinner and lighter than the Schöningen javelins, and the targets were much smaller than horses.

05 Humanity Branches Out.r.qxd 1/29/02 5:05 PM Page 161

Humanity Branches Out | 161

Some historic groups, including Australian aborigines and the Aztecs of central Mexico, had spears that could injure a large animal from a distance, but for this purpose, the spears had to be supplemented by the “spear-thrower” or atlatl. This is a wooden or bone rod that is hooked at one end to accommodate a dimple or notch in the dull end of a spear. The spear shaft is laid along the rod and the rod is extended from the hand to lengthen the arm. The resulting mechanical advantage allows the spear to be thrown much harder and farther than it could be otherwise. The Schöningen spears are too large and inappropriately shaped to be atlatl darts, and atlatls are known only from much younger sites, after 20,000 years ago.

* * *

The broken and cut-marked horse bones found at Schöningen demonstrate that the people obtained large animals, even if their spears were relatively ineffective. Cut-marked or bashed bones permit the same conclusion at other 500,000- to 400,000-year-old sites, including Torralba and Ambrona in north-central Spain, Boxgrove in southern England, and Elandsfontein in the Western Cape Province of South Africa. Still, by themselves, the tool-marked bones don’t reveal how often the people obtained animals, that is, how successful they were. To address this, we must consider not just the tool-marked bones, but also their abundance relative to bones that lack tool marks or to bones that were damaged by carnivore teeth. Such observations are available from only a handful of sites, but where they exist, they suggest that late Acheulean people did not obtain large mammals very often.

This point is illustrated from the site of Duinefontein 2, on the Atlantic coast of South Africa, about 50 kilometers (30 miles) north of Cape Town.

05 Humanity Branches Out.r.qxd 1/29/02 5:05 PM Page 162

162

| THE DAWN OF HUMAN CULTURE

Like so many other buried sites, Duinefontein 2 owes its discovery mainly to commercial activity. The Electricity Supply Commission of South Africa owns the land, and in 1973, they were planning to build a nuclear power plant nearby. They brought in a bulldozer for subsoil testing, and by luck, a few days later one of the authors of this book (Klein) was hiking nearby with friends. They encountered a bulldozer trench, and on the spoil heap at one end, they saw numerous animal bones, including a broken elephant tusk. When they entered the trench, they noticed a line of bones and stone artifacts protruding from the walls about 60 centimeters (2 feet) below the surface. Two days later, a small test excavation showed that the objects lay on an ancient land surface. The excavation was enlarged in 1975, but power plant construction then made the site inaccessible for more than a decade. The contractors carefully marked the location on their maps, and in the mid-1990s, the author and his colleagues established that the site was still intact. In five seasons between 1997

and 2001, they then exposed the ancient surface over more than 490

square meters (5340 square feet), and they carefully plotted the position of every artifact and bone they uncovered.

The large excavation showed that the bones tend to occur in clusters that probably mark individual carcasses. The most common species are wildebeest, kudu, and a large extinct relative of the African buffalo. Occasional bones of hippopotamus, reedbuck, and other water-dependent creatures show that a marsh or large pond stood nearby. The artifacts include whole and broken Acheulean hand axes, well-made flake tools, and the cores from which they were struck. Tools and bones often occur immediately alongside one another, and their contemporaneity is not in doubt (Figure 5.8). There is no way to estimate how 05 Humanity Branches Out.r.qxd 1/29/02 5:05 PM Page 163

Humanity Branches Out | 163

0

T

T

10

A

T

T

20

T

A

A

30

T

40

T

V4

T

T

50

T

T

T

60

70

T

80

90

100 cm E

T A

T

A

S

T

A

T

A = artifact

T

T = tortoise fragment

V5

A

SOUTH

T

AFRICA

A

T

A

Duinefontein 2

FIGURE 5.8

Artifacts, buffalo vertebrae and other bones, and fragments of tortoise carapace scattered across the surface of excavation squares V4 and V5 at Duinefontein 2.

05 Humanity Branches Out.r.qxd 1/29/02 5:05 PM Page 164

164

| THE DAWN OF HUMAN CULTURE

long the accumulation took to form, but decades or centuries are more likely than months or years.

The Duinefontein deposits are dune sands that can be dated by luminescence, a cousin of the Electron Spin Resonance method. The luminescence technique employs heat or light to release electrons that are trapped in crystal flaws within individual sand grains. As the electrons are released, the sand grains glow and the intensity of the glow (luminescence) is directly proportional to the number of released electrons. Sunlight will also empty the traps, which means that the released electrons must all have accumulated since the sand grains were last exposed at the surface, that is, just before they were buried. The rate of accumulation is directly proportional to natural, low-level, background radioactivity in the soil, and this can be measured in the field today.

Measurements conducted over a year at Duinefontein provided the local annual radiation dose, and reassuringly, they suggested nothing unusual, such as leakage from the power plant. In practice, luminescence dating often faces some daunting challenges, including the possibility that the annual radiation dose has varied through time as ground water circulation added or subtracted uranium or other radioactive elements. If potential problems can be overcome or placed aside, the calculation of a luminescence date can be visualized as the number that results when the total number or released electrons is divided by the assumed yearly rate at which they accumulated.

Application of luminescence dating at the level of the ancient Duinefontein surface indicates that the sands—and the associated artifacts and bones—were buried about 300,000 years ago. Since the bones mostly lack the superficial cracking that comes from exposure to the elements, it is unlikely that they lay on the surface long before burial, 05 Humanity Branches Out.r.qxd 1/29/02 5:05 PM Page 165

Humanity Branches Out | 165

and 300,000 years must closely approximate their geologic age. The site thus formed near the end of the Acheulean era.

So far, Duinefontein 2 has provided no human remains, but if it had produced a skull, this would probably resemble one found at the Florisbad spring site in the South African interior. The Florisbad skull has been tentatively dated by Electron Spin Resonance to about 260,000

years ago, and it is nicely intermediate between the skulls of
Homo heidelbergensis
of 500,000 years ago and those of near-modern Africans after 130,000 years ago. Thus, like
heidelbergensis,
it had thick walls and a broad, massive face, but like much later people, it had a relatively steep and convex forehead and a flat, non-projecting face. It anticipates modern skulls in broadly the same way and to about the same degree that the skulls from the Sima de los Huesos anticipate those of the Neanderthals, and it thus provides direct proof that the modern human and Neanderthal lines had diverged by at least 250,000 years ago.

Archeologist Richard Milo of Chicago State University has carefully scrutinized every Duinefontein 2 animal bone for damage, and he has found stone tool marks like those at Schöningen. However, his research also shows that tool marks are far rarer than carnivore tooth marks and that the tooth marks are about as common as they are on bones at the Langebaanweg paleontological site, 60 kilometers (36 miles) north of Duinefontein. At Langebaanweg, the bones also occur in clusters that represent carcasses scattered on an ancient land surface, and they come from broadly the same range of animals as at Duinefontein 2.

However, Langebaanweg dates from about 5.5 million years ago, 3 million years before the oldest stone tools, and it understandably lacks artifacts and tool-marked bones. Duinefontein 2 provides nothing to determine whether people 300,000 years ago mainly hunted or 05 Humanity Branches Out.r.qxd 1/29/02 5:05 PM Page 166

166

| THE DAWN OF HUMAN CULTURE

scavenged, but the similarity in bone damage to Langebaanweg implies that whatever they did, their impact on other large mammals was negli-gible, and they obtained few carcasses overall. The rarity of tool-marked bones at Ambrona, Torralba, Elandsfontein, and a handful of other like-aged sites provisionally supports the same conclusion.

Why then are bones and artifacts so numerous and so closely associated at each site? The answer is probably that each occurred near a water source that attracted both people and animals over a long interval. The people may have only rarely interacted with other animals when they came to drink, and they might not even have seen many of the bones, which could have been previously trampled into the subsoil or obscured by vegetation. From our perspective, 300,000

or more years later, it may appear that the bones and artifacts were deposited at the same time, and in a geologic sense they were.

However, they could easily have arrived weeks, months, or even years apart, and we would have no way of knowing.

If we are correct that Acheulean people rarely obtained large animals, the reason was probably their limited technology, and a key consequence was small human population size. Duinefontein 2 provides a way to test this independently, using bones of the angulate tortoise which occur abundantly on the ancient land surface. Tortoise collection requires no special knowledge or technology, and local stone age people have engaged in it for tens of thousands of years. Almost certainly, they always took the largest specimens first, since these are the most visible and the most meaty, and when the number of collectors increased, average tortoise size declined. The Duinefontein 2 tortoises represent natural deaths on the ancient land surface, but their average size must still reflect the intensity of contemporaneous human collection, and on aver-05 Humanity Branches Out.r.qxd 1/29/02 5:05 PM Page 167

Humanity Branches Out | 167

age, they were about as big as angulate tortoises can get. Tortoises at sites associated with early anatomically modern humans, dated between 130,000 and 60,000 to 50,000 years ago, average significantly smaller, and those from sites that postdate 50,000 years ago are smaller yet. The implication is that human populations were especially small in late Acheulean times, that they increased later on, and that they reached historic levels only after the dawn of human culture.

* * *

Like other African late Acheulean sites, Duinefontein 2 differs from its European counterparts in the species of animals represented, in the kinds of stone used to make tools, and in other details. In addition, the Africans and Europeans surely belonged to different evolutionary lineages. Yet, there is nothing at the various sites to suggest a significant behavioral difference, and on each continent, behavior appears to have been equally primitive by modern standards. Africans and Europeans remained behaviorally similar—and still primitive—until about 50,000 years ago, when the Africans added modern behavior to modern anatomy. For a brief period, Africans and Europeans then differed sharply in behavior, but the modern behavioral mode gave the Africans a competitive advantage, and they soon spread it throughout Eurasia. By 30,000 years ago, people everywhere were modern in appearance and they were once again similar in behavior.

06 Neanderthals.r.qxd 1/29/02 5:05 PM Page 168

* * *