A team working in South Africa claims to have found the earliest known sleeping mats, made of plant material and dated up to 77,000 years ago - 50,000 years earlier than previous.
     Early Homo sapiens were nomads who lived by hunting and gathering, often creating temporary camps. One of the best studied of these is Sibudu Cave, a rock shelter in a cliff face above South Africa's Tongati River, about 40 kilometres north of Durban. Sibudu was first occupied by modern humans at least 77,000 years ago, and continued a favoured gathering place over the following 40,000 years. A team led by Lyn Wadley, an archaeologist at the University of the Witwatersrand, Johannesburg, has been excavating at Sibudu since 1998, uncovering evidence for complex behaviours, including the earliest known use of bows and arrows.
     Many of the layers featured large, 1-centimetre thick swaths of plant stems and leaves,  most covering at least three square metres. The team suspected that these were the remains of bedding, but the earliest previous evidence for sleeping mats is only between 20,000 and 30,000 years old, at sites in Spain, South Africa, and Israel, where similar but more fragmentary arrangements have been found.
     The swaths, which dated from 77,000 to 58,000 years ago, were made from sedges, rushes, and grasses that grow by the river. Under the microscope, the material showed signs of compression and repeated trampling. In the earliest layer the team found the leaves of Cryptocarya woodii, also known as Cape laurel, or the 'bastard camphor tree,' an aromatic plant whose leaves are used in traditional medicines even today. The leaves contain several chemical compounds that can kill insects.
     Microscopic analysis also suggests that the bedding had been burned, perhaps to eliminate insect pests and get rid of accumulated garbage, so that new layers of bedding could be laid down.
     Among the plant remains, Wadley's team also found tiny fragments of chipped stone and crushed, burnt bone - evidence that these were also work surfaces, where tools were fashioned and food was prepared.

Edited from Science, Popular Archaeology (8 December 2011)