Science: Following in Eve's footsteps

IN THE West Coast National Park in South Africa, about 100km north of Cape Town, are three footprints. At a glance, they look quite ordinary in size and shape, like those made by any modern woman walking through soft sand. The difference is that these are embedded - fossilised - in the rock. In fact, they were made 117,000 years ago and are the oldest human footprints ever discovered.

They were found in 1995, by geologist David Roberts. But he held off announcing the discovery, despite its momentous importance, until last year. Even then it was too soon. Now scientists are worried about how many more years these footprints will last, for while they have survived everything nature has thrown at them, tourist interest is literally wiping them away.

The three prints are believed to have been made by a woman, 5ft 3in (1.6m) tall, strolling barefoot in wet sand after a rainstorm. The big toe, ball, arch and heel of the foot are well-defined, making the footprints - which were eventually fossilised - an important clue to understanding when anatomically modern humans emerged.

Roberts found the footprints in September 1995 after uncovering an ancient stone core, the flakes of which were used by early man for scouring and other tasks. "On a hunch" he went looking for traces of its maker. "I scrambled up and down these rock faces for hours finding absolutely nothing," he said on announcing the discovery last year. "Then I looked down and found that footprint there. The chances of finding something like this are a million to one."

Once the prints were made, they were covered very quickly with windblown sand on a slope that eventually turned to sandstone after being buried under pressure for tens of thousands of years. "They had to be buried for a very long time to turn to rock," said Roberts. Set on a pristine lagoon beach, the sandstone rock in which the footprints are embedded is so fragile that it crumbles quite easily. Even running one's hand over the surface causes fine grains of sand to come away.

What is so exciting about the footprints? Theory suggests that all human life - well before the emergence of Homo sapiens - is descended from one common female ancestor, known as "genetic Eve". We do not know whether the prints are hers (the chances of that are incalculably small). But experts say they were made at the right time and place to fit her profile.

"What we do know from other sites in South Africa is that there were anatomically modern humans living here. It's like putting together the pieces of a puzzle," says Janette Deacon, an archaeologist at South Africa's National Monuments Council.

Ms Deacon has noticed growing interest in the site from people who want to share something - anything - with this woman from so long ago. "There's been no tailing off of interest in the site. That's exciting, because it's engendering in people a sense of history."

But the public's fascination with their cultural heritage has become a threat to the footprint trail. In fact, it has ruled out scientists' hopes of preserving them in situ. The effects of the visiting hordes who have beaten a path to see this older trail are clearly visible. There is already graffiti dotting the rocks around the footprints. People visiting the site have been spotted clambering on to the brittle dune rock to stand inside the footprints - prompting fears that if left unchecked, irreparable damage will result.

Conservationists want to keep those people away. But their case is not helped by the fact that the footprints are on a popular beach in a picturesque national park where last Christmas the visitors were arriving in about 200 cars a day. Large numbers are expected this Easter, so no chances are being taken. Guards are already on site to patrol the area and prevent further damage. A transparent Perspex screen will soon also be suspended over the footprints to prevent people putting their feet in them.

The weather is another foe, and one that cannot be controlled. The rock has already slipped slightly from its original position through a combination of wind and wave action, according to Craig Morkel of Corporate Image, one of the organisations involved in the talks about the future of the footprints. "In the long term, the wind and wave action below will undercut that rock and it will slide into the water," Morkel adds. "It is sad for all of us, but removal has been reluctantly accepted. We understand and accept it now."

Ms Deacon agrees that any damage could not be repaired. "There is no way the footprints are going to remain undamaged there," she says. "The rock beneath the surface is very soft and fragile, and if you don't look after it you could end up with just a pile of sand."

Scientists, conservationists and others interested in preserving the footprints have banded together and decided they must be moved temporarily to the South African Museum in Cape Town - if it can be done safely. A host of specialists have been consulted over the best way to move the rock prints, including Briton Keith Taylor, an expert in stone conservation, who has agreed to inspect the site during a visit to the country in May.

Meanwhile, the authorities at the West Coast National Park have bowed to necessity. "Unfortunately, we have to go for second prize at this stage," says the park's warden, Otto von Kaschkepark. As the millennium approaches, he anticipates continuing interest in the footprint trail. "There is a need by modern man to find his roots and his origins. This could be a tremendous draw."

The park plans to build a visitors' site that will measure up to international standards, and then it will attempt to claim back the footprints. "We will try to soften the blow by putting a very good replica in its place and, hopefully, at some time stage we will be able to return the original," says Mr von Kaschkepark.

But this still underlines the troubling question: how do we look after the interests of the past while not cutting it off from the present?