Earliest Human Bedding Didn't Let The Bed Bugs Bite

NewScientist.com
Thursday, December 8, 2011

After a hard day hunting and gathering, humans 77,000 years ago could count on a good night's mosquito-free sleep on a comfy bed of grass and leaves. Archaeologists have discovered the oldest evidence of humans using plant bedding, 50,000 years before it appears anywhere else.

Many animals make beds for themselves, says lead author Lyn Wadley of the University of the Witwatersrand in Johannesburg, South Africa, but what's interesting in the new find is the way the owners managed their bedding. To keep it clean and pest-free, they burned it.

Wadley's team has spent the past decade excavating a rock shelter called Sibudu, situated high in a cliff surrounded by forest and near the Uthongathi river in South Africa. People lived there on and off between 80,000 and 38,000 years ago, in a complex society that used stone tools and even madeglueand  simple ornaments.

Wadley found layers of plant material on the cave floor that date from 77,000 years ago onwards - mostly grasses, sedges and rushes. These could not have grown in the dry shelter, so people probably collected them near the river.

BURNING THE BEDS

Wadley thinks the bedding was used to make a clean area for sitting, working, eating and sleeping. Tools and other artefacts were found buried within it.

Intriguingly, all the layers of bedding that are 73,000 years old or younger show signs of burning, which Wadley suggests may have been the result of routine cleaning. Burning the plants would have killed pests and diseases. That the cave's occupants needed to do this, he says, may suggest they spent extended periods of time in the shelter, so had to keep it clean.

It seems the bed-makers were selective about the plants they would sleep on. A range of trees grow in the region, but only the Cape laurel (Cryptocarya woodii) was used.

Cape laurel leaves give off insecticidal chemicals, so they would have repelled insects and their larvae - including malarial mosquitoes. That would make the cave bedding the earliest evidence of humans using medicinal plants, although other animals have similar tricks: common starlings oftenuse insecticidal plants in their nests to repel blood-sucking insects.

OLD KNOWLEDGE

The behaviours may have started sooner than this site shows. "I would guess that right back until the earliest anatomically modern humans, people would have known which plant to choose," says Wadley.

Chimpanzees also build nests, and there is some evidence that they too include insecticidal plants. Fiona Stewart of the University of Cambridge, UK, spent several nights sleeping in chimp nests, and found that insects bit her less than when she slept on the ground.

"Perhaps this purpose of bedding has been continuous throughout human evolution," Stewart suggests.