Even more than 200,000 years ago, people apparently liked to lie comfortably and hygienically: In the South African Border Cave, researchers discovered traces of grass beds that had layers of ash as a base. The powdery material probably served to ward off parasitic insects, say the scientists. They also discovered remains of the camphor bush in the layers, which also speaks for a targeted suppression of ticks and the like.
Not only humans like to be comfortable when resting – in addition to other animal species, great apes are also known to make sleeping nests from parts of plants. It is therefore obvious that similar behaviors are also deeply rooted in the history of human development. Since the organic matter is easily transient, there is generally little evidence of the use of plant materials. The oldest known traces of the use of plants as litter in human habitat are 77,000 years old and come from the Sibudu Cave in South Africa. The current finds are now much older evidence of these practices.
Oldest evidence of litter material
The finds come from the so-called Border Cave in South Africa, which according to previous discoveries served as a shelter for people over 200,000 years ago. As the researchers working with Lyn Wadley from the University of the Witwatersrand in Johannesburg report, they encountered unusual deposits in the back of the cave in very old layers of the soil, which they then examined more closely in the laboratory.
The electron microscopic and chemical analyzes of the material and the inclusions in the deposits showed that they contained remains of broad-leaved grasses from the Panicoideae family. The researchers report that they can still be found in the area in front of the cave today. The location and the amount of grasses suggest that they were deliberately brought into the interior of the cave over 200,000 years ago. “We assume that people both worked and slept on the grass surface because debris from stone tool making is mixed with the grass debris. We also found tiny remnants of red and orange ocher grains in the plant material that people might use to color their skin, ”says Wadley.
Ash against ticks and co
Investigations of the deposits also showed that the grass material was apparently placed on layers of ash. The evidence from the analyzes suggests that the ash underlay of the plant material sometimes came from older grass litter that was burned to clean the cave. In other cases, however, it is also becoming apparent that wood ash from fireplaces was used as a clean base for a new layer of bedding, the scientists report.
“We suspect that moving grass litter to ash was a deliberate strategy to ward off parasites,” says Wadley. According to the scientists, well-known human practices speak for this reason. The use of ash as an insect repellent is known from various cultures, because the fine powder represents a barrier for these animals: ash blocks the insects’ breathing and biting apparatus and dehydrates them, which is why they avoid the material. Another finding from the analyzes of the deposits speaks in favor of the targeted use of strategies for defense against parasites: The researchers found remains of the camphor bush (Tarchonanthus camphoratus). This plant is still used in rural East Africa to deter insects.
Although the hunters and gatherers of the time probably did not live in the cave permanently, the method at least had the potential to extend the occupancy time, say the researchers. “Such strategies likely had health benefits that benefited these early communities,” says Wadley. “Our results show that 200,000 years ago, near the origin of our species, people could create fire at will and use it wisely: They used fire, ashes and medicinal plants to ensure clean, pest-free storage,” the anthropologist sums up .
Source: University of the Witwatersrand, Technical article: Science: 10.1126 / science.abc7239