Saturday, 10 December 2011

Early Humans Had A Good Grasp Of Botany

Dr Chris Miller, an archaeologist from the University of
Tubingen, excavates the layers of ash and plant bedding
Some of the most significant evidence for the lifestyle of the early members of our species come from the series of limestone caves which line the coast of South Africa. Over the years, archaeologists have found the remains of our ancestors' food, their possessions, and through ancient cave art, a glimpse into the inner workings of their mind. Now anthropologists working at the Sibudu rock shelter in the KwaZulu province, South Africa, have found evidence to suggest that they were able to use plants in their industries.

The team, led by Lyn Wadley of the University of Wiltwatersrand in Johannesburg, were excavating an ancient cave, when they uncovered a series of strange layers within the sediments which made up the cave's floor. Closer examination revealed that the compacted layers were composed of organic material, specifically sedges and rushes, and showed that they were actually mats of plant material between one and three metres squared.

Such mats have been discovered before, indeed at the same cave. Yet the date of these artefacts makes them special: they were at least 50,000 years older than the oldest reed beds previously discovered, dating them between 70,000 and 38,000 years old. The 15 layers were incredibly well preserved. Each individual mat was composed of two parts: a compacted bed of reeds and sedges, over-layed by a tissue paper-thin covering of flat, wide leaves.

Close analysis showed that they were of the species Cryptocarya woodii, whose leaves have insecticidal properties. This suggests that our ancestors had an intimate knowledge of the plants around them. Layers of ash found between the mats after 73,000 years, showed that the old ones were burnt. It is likely that this would have helped pest and parasite control within the cave. The old mats would have been very dry, making a conveniently placed fuel-source for fires.

The discovery was well-timed as it has halted the plans for housing developments near the archaeological site, preserving vital evidence and potential future discoveries into the way our ancestors lived. It is studies such as these which provide perhaps the greatest insight into early human existence. As large projects such as mapping human migration give us the bigger picture, the insight gleaned from the Sibudu cave is of a smaller scale, yet it is a picture of perfect clarity.