Researchers have discovered the oldest known human hair which could explain human evolution from many early human ancestor fossils
Each white, round fossil turd, or coprolite, is roughly 0.8 inch (2 centimeters) across. They were found embedded in sediments 195,000 to 257,000 years old.
The sizes and shapes of the coprolites and their location suggest they came from brown hyenas, which still live in the region's caves today.
Until now, the oldest known human hair was from a 9,000-year-old Chilean mummy.
It's not clear which species the newfound human hairs are from, since the human fossil record for this time span is exceedingly limited, the researchers say.
But, the hairs' age "covers just before when we think modern humans emerged, and overlaps with the existence and end of Homo heidelbergensis," said study co-author Lucinda Backwell, a paleoanthropologist at the University of the Witwatersrand in Johannesburg, South Africa.
"The hairs could belong to either of them, or of course to a species not yet recognized," she added.
Backwell and her colleagues used tweezers to extract 40 fossilized hairs resembling glass needles from one of the hyena coprolites.
Scanning-electron-microscope images revealed wavy bands of scales on the hairs-a pattern typical of modern primates, with human hair being the closest match.
Modern brown hyenas are known to hunt baboons and other large mammals when they are rearing cubs, according to the researchers.
But, for the most part, the animals are scavengers; so the research team thinks the human hair came from a corpse the hyenas stumbled upon.
According to Backwell, the hairs in this particular coprolite did not yield any DNA. But, she noted that there seem to be hundreds of fossil droppings in the one South African cave alone and plenty more in sites across the region.
"The contents of such dung could shed light on the ancient environments where early humans and their ancestors once lived," she said.
"It would be extremely interesting if this work kicked off some concerted effort to go back to sites where fossil dung has been found before," said Pat Shipman, a paleoanthropologist at Pennsylvania State University.
"This could give us more evidence to answer questions being debated these days on how and when and where and why modern humans arose," she added.