SCIENCE / Gods, Graves and Scholars: From the scattered human remains in a Stone Age pit, scientists are trying to piece together a puzzle that may reveal the dawn of religious belief. David Keys reports

SPANISH SCIENTISTS are trying to solve one of the great riddles of Stone Age archaeology. In a remote cave in the middle of a highland massif in northern Spain, a team of archaeologists and anthropologists is excavating a pit which almost certainly contains up to 100 disarticulated human skeletons that are a quarter of a million years old.

It is the largest, and undoubtedly the most important early Stone Age collection of human bones found anywhere in the world. Last week 50 of the bones went on display at the Natural History Museum, London, as part of an exhibition entitled The First Europeans.

The Spanish team, from Madrid's Complutense University and Natural Sciences Museum and Tarragona University, has so far investigated about a quarter of the pit and has unearthed 700 disarticulated human bones, representing at least 23 individual corpses,

but probably more than 30. By the time the excavation in the Sierra de Atapuerca, near Burgos, is completed, probably well into the next century, thousands of bones are likely to have been found.

Meanwhile anthropologists are piecing the bones together. Complete skeletons of this antiquity - never before discovered - will cast valuable new light on human evolution in the period immediately before the emergence of Neanderthals and modern humans.

These 250,000-year-old prehistoric people, an intermediate stage between ape-men and anatomically modern humans, were descendants of the first tool-using humans, who emerged 2 million years earlier, almost certainly in Africa. They were also probably the ancestors of the Neanderthals, who inhabited Europe before modern humans, our ancestors, arrived. However, detailed scientific examination of the bones from Atapuerca is only just beginning, so no definite conclusions have been reached as to their exact place in human evolution.

Certain facts are known. The Atapuerca individuals had quite large heads with large brains (1300-1500cc), similar in size, but probably not in quality and complexity, to those of modern humans. Their general build was robust, with males standing up to 1.7m tall and weighing, on average, an estimated 65kg. But scientific examination of the reassembled skeletons will for the first time be able to determine the relative sizes of early Stone Age men and women, their adaptation to climatic conditions, their ability to run long distances, and the range of physical types within a single community. These details and the degree of complexity of their society will emerge only after the Spanish team, led by university and museum academics Juan Luis Arsuaga, Eudald Carbonell and Jose Maria Bermudez de Castro, have completed their investigations.

Evidence from Atapuerca and other sites suggests early humans of the same period lived by hunting, scavenging and gathering roots and berries. It is likely that they knew how to make fire, that they wore animal-skin clothes and had a rudimentary language, with a vocabulary of a few hundred words. Most anthropologists think that they probably moved around in small polygamous groups of 10 to 20 individuals - typically perhaps three adult males, five adult females and around seven children.

However, much of what scientists thought - or assumed - about their behaviour and social organisation could well be thrown into considerable disarray by the discoveries being made in Spain. At the heart of the debate is how to explain why dozens - probably 50 to 100 - corpses ended up in a pit in the middle of a hill a quarter of a million years ago. Already it seems these early humans could have lived in much larger social groups than we have hitherto assumed.

One possible explanation for so many skeletons being found in one place is that they were dragged into the cave by hungry carnivores, perhaps jaguars or leopards. However, very few animals would subsist solely on a diet of humans, and no remains of other prey species have been found in or near the pit. Although there is some evidence of teeth-marks on some of the bones, these could well have been inflicted by the occasional carnivore chewing on corpses which were already there.

In slightly less ancient deposits above the human bones, scientists have found the remains of hundreds of cave bears, who presumably used the cave for hibernating after it was used by humans. Perhaps significantly, cave bears seem to have avoided the place while it was being used to receive dead humans, which tends to counter the idea that the human skeletons were dragged there by animals.

Another suggestion invokes a natural disaster. Some archaeologists have floated the idea that the entire group of 50 to 100 individuals all perished in a single catastrophe - a flash flood or the collapse of the cave entrance. Opponents of this hypothesis, however, point out that no artefacts have been found in or near the pit, and that it is extremely unlikely that so many individuals would have been gathered together inside a cave at one time.

Research has shown the cave complex consists of up to 11km (7 miles) of caverns and passages - and Spanish archaeologists have discovered three large campsites near the cave entrance which they believe to have been used by communities living at roughly the same time as the individuals unearthed in the pit. Hundreds of stone tools and animal bones - food debris - have been unearthed in a series of excavations.

The most likely explanation of how the bodies came to be in the pit is also the most revolutionary. Much of the available evidence suggests that the pit - or the cave floor adjacent to it - was used by early humans as a mortuary area. If this is correct, then humans would probably have brought their dead into the cave as some sort of funerary procedure. This has immense implications for how we modern humans view the thought processes of our non-modern early human predecessors.

If, by 250,000 years ago, early humans had developed special traditions for keeping their dead relatives together in one secure place, then this hints at a concern for the welfare of the dead, perhaps even a concept of an afterlife - and, if true, this in turn suggests the beginnings of religious belief.

Until now, the earliest evidence for pre- modern human funerary procedures has come from Neanderthal sites much later than the Atapuerca site. Deliberately excavated graves have been found in France, at La Chapelle aux Saints and at La Ferrassie (both around 50,000BC), Le Moustier (c 40,000BC) and Roc de Marsal (c 90,000BC). At a place called Teshik-Tash in Uzbekistan, in central Asia (before 50,000BC) archaeologists found a Neanderthal grave, apparently surrounded by ibex horns; while at Shanidar in Iraq (70,000BC), flowers may even have been placed by Neanderthals on their relatives' graves. At Krapina in Croatia (70,000BC) dozens of corpses appear to have been gathered in one place.

Juan Luis Arsuaga, one of the leaders of the excavations, takes the view that the corpses were probably thrown into the pit by other humans: 'I believe that there is a possibility that this pit and its contents are evidence of some sort of embryonic religious belief.'

If the gathering together of a community's dead in a single place - perhaps over several generations - indeed represents a concern about what happens after death, then it implies that these pre-modern humans did possess a need, and an ability, to envisage the future. It suggests that they were able to think forward and to plan in abstract terms - one of the key qualities that separates humans from other animals.

If, in turn, this concern about death represented an embryonic religious belief, then it would cast important additional light on the origins of religion. Certainly, recent hunter- gatherer societies have had a powerful belief in a spirit world. And it may be that religion had a dual origin - an attempt to cope with grief,

by disposing of the dead in ritualised ways, as well as a search for an answer to the eternal question that haunts mankind: what happens after death?

Although at Atapuerca most of the information gathered so far points towards the deliberate disposal by humans of their community's dead, there is, however, one important piece of evidence which at first sight, at least, does not fit in with this mortuary hypothesis.

Anthropologists have now succeeded in determining the age at which 21 of the individuals died. Most perished in their teens with almost 40 per cent of them dying between 17 and 21. Less than a quarter lived beyond their very early twenties.

It is virtually impossible for this to be the typical 'age at death' profile of a community - because if it was, then the community could not have survived. People would simply not be surviving long enough to wean and bring up more than one or two children, and, given the inevitably high infant mortality rate, the community would have died out very quickly.

The only other explanations would be that only the most active members of the community were being accorded a proper funeral, or that older individuals were disposed of elsewhere, or that the assemblage of skeletons is atypical - and perhaps represents the results of a battle between two rival communities. If the latter is correct, then it seems that young women of child-bearing age were killed alongside their menfolk. This is somewhat at odds with the way anthropologists suspect conflicts were conducted, with females usually being captured and spared, making that theory unlikely.

Answers to the riddle of Atapuerca will only come after all the available evidence is assembled. But anthropologists are convinced that the fact that these questions are now being raised makes the site one of the greatest Stone Age discoveries ever.-

(Photographs omitted)