Tsamkxao Ciqae was on a track so old an ice age separated the human tracks from the present. He and two fellow Namibian San trackers, C/wi G/aqo De!u and C/wi /Kunta, were tracking spoor left 17000 years ago and in doing so providing some insight into why Stone Age people were hanging out in caves all those millennia ago.The trackers come from the town of Tsumkwe in Namibia and were invited to visit several caves in the Pyrenees by German archaeologists Andreas Pastoors and Tilman Lenssen-Erz.The Germans had studied the rock art but felt that to obtain a better understanding of what early humans were doing in these caves they would need someone to interpret the footprints found in the more remote recesses of the sites."We wanted to do more than just measure the footprints," said Lenssen-Erz.The academics located the three San trackers, who work as hunting guides in Namibia, and invited them to Europe.Lenssen-Erz said he was amazed at what the three were able to pick up from the spoor."They were able to identify 28 individual tracks, identifying sex and age." The oldest set of tracks were from a 60-year-old man, the youngest from a three-year-old.For the first time researchers had an idea of who had been going into the caves: it wasn't one group of the population, it was a cross-section.In the Tuc d'Audoubert cave the trackers were able to solve a 100-year-old riddle. Researchers were puzzled by prints that appeared to have been left by people walking on their heels."It has been thought that they were involved in some sort of ritual," said Lenssen-Erz, suggesting it could have been a dance.After an hour of studying the tracks, the San came to their own conclusion. A man aged 38 and a boy 15 had come to collect clay. Why they were walking on their heels, they couldn't say."Later they said it might be that they were trying to hide their identity for some reason, because you recognise someone by their toes," said Lenssen-Erz.The archaeologists want to continue with the project, finding more trackers and taking them to other caves in Europe.