Border Cave is a deep gash in a cliff face, high in the Lebombo Mountains of South Africa. Sheltered from the elements, the spot has yielded bones, tools, and preserved plant material that paint a detailed picture of the lives of human inhabitants for more than 200,000 years. Now, there’s a new sketch emerging: Plant remains point to evidence that the cave’s occupants used grass bedding about 200,000 years ago. Researchers speculate that the cave’s occupants laid their bedding on ash to repel insects.