Ancient egg inscriptions

According to the BBC ancient ostrich shell fragments found in South Africa are among the earliest examples of the use of symbolism by humans. Etched shells from Diepkloof Rock Shelter in Western Cape have been dated to about 60,000 years ago.

The researchers, who have investigated the material since 1999, argue that the markings are almost certainly a form of messaging - of graphic communication.

"The motif is two parallel lines, which we suppose were circular, but we do not have a complete refit of the eggs," explained Dr Pierre-Jean Texier from the University of Bordeaux, Talence, France. "The lines are crossed at right angles or oblique angles by hatching. By the repetition of this motif, early humans were trying to communicate something. Perhaps they were trying to express the identity of the individual or the group," he told BBC News.

Possibly the earliest examples of human conceptual thought are the pieces of shell jewellery discovered at Skhul Cave in Israel and from Oued Djebbana in Algeria. These artefacts are 90,000-100,000 years old.

Shell beading from 75,000 years ago is also found at Blombos Cave in South Africa, as well as a number of ochre blocks that have engravings not dissimilar to those at Diepkloof. However, the significance of the Diepkloof finds may lie in their number, which proves such markings could not have been simple doodlings.

The team's experiments suggest that the colouration of the fragments is natural and not the result of the application of pigments. The group was able to reproduce similar hues by baking pieces of shell near a fire. Professor Chris Stringer, of London's Natural History Museum, said the find was important.

"Here we've got something that we can compare with later material that clearly does have important signalling value in the populations," he told BBC News. "It's a very nice link between the Middle Stone Age, the later Stone Age and even recent population in South Africa. One question now is whether this is a special site, or as we excavate more sites will we find this material is more widespread?"

More fascinating stuff. What more to say?