Early humans knew how to make comfy, pest-free beds, study says

Some of the earliest humans learned to control fire, create comfortable beds and even keep pests out of them 200,000 years ago, according to a new study.

Researchers discovered fossilized grass beds sitting atop layers of ash in Border Cave, an archaeological site in South Africa.

The well-known cave sits on a cliff between eSwatini (formerly Swaziland) and KwaZulu-Natal in South Africa.

Inside, toward the back of the cave, researchers found bundles of panicoid grass, which is found in warm temperate areas. The grass had long since fossilized, and the scientists dated it back to 200,000 years ago.

Previously, the oldest known use of plant bedding by humans from the Stone Age dated to 77,000 years ago.

Plant material is rarely well preserved in the fossil record, which makes understanding the use of comfortable plant-based bedding used by our ancestors difficult to track over time.

The grass was arranged on layers of ash, which serves as a deterrent to pests because insects can't crawl through its fine texture, it dehydrates them and it can also block their breathing and biting.

The researchers also found remains from the camphor bush on top of the grass from the oldest bedding inside the cave. This plant is still used as a way to deter insects in rural areas of East Africa.

The study published last week in the journal Science.

Ash: The key to a cozy bed

"We see the cognitive foundations for later innovations from close to the origin of our species," said Lyn Wadley, lead study author and honorary professor of archaeology at the University of the Witwatersrand in Johannesburg, in an email. "We see people's strategic control of the environment through the deliberate creation and use of fire and its products."

Wadley said she was amazed that fragments of grass could survive for 200,000 years, but their structures were so well preserved that they could identify the type of grass used in the bedding.

Some of the ash that served as the foundation beneath the grass bedding, the researchers determined, was actually the remnants of older bedding that was purposefully burned. Burning old bedding was a way to clean the cave and destroy any pests attracted to it.

There were also layers of wood ash gathered from the nearby fireplace in the cave added to help clean the bedding. Evidence of stacked fireplaces were found throughout the cave, dating from 38,000 to 200,000 years ago.

"Control of fire was an important technological foundation," Wadley said. "Through the use of ash and medicinal plants to repel insects, we realize that they had some pharmacological knowledge."

Within the bedding, the scientists found evidence of tiny grains of red and orange ocher, a natural clay pigment used by early humans. This suggested they were wearing it on their skin or using their beds as workplaces if they were making objects that involved ocher.

These early humans likely lived in hunter-gatherer societies, meaning these prehistoric ancestors of ours moved around often, but using fire and ash to clean their camps would have allowed them to extend their stay in the cave.

After burning old bedding, they would bring in fresh grass to create new, clean beds, Wadley said.

"People seemed to understand the health risks brought by pests and tried to eliminate or repel them from their camps," she said.

"This involved planning as well as technological competence, knowledge of plants and so on. At Border Cave we also found charcoal from burned camphor wood and perhaps medicinal smoke was used to dispel flying insects."

The last of the oldest grass beds they found in the cave had not been burned, meaning the site was eventually abandoned. But there is evidence that the cave was used as an intermittent shelter for humans over the span of 230,000 years.