Oldest Human Hair Found in Hyena Poop Fossil?

Charles Q. Choi
for National Geographic News
February 6, 2009
The oldest known human hairs could be the strands discovered in fossil hyena poop found in a South African cave, a new study hints.

Researchers discovered the rock-hard hyena dung near the Sterkfontein caves, where many early human ancestor fossils have been found.

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.

Until now, the oldest known human hair was from a 9,000-year-old Chilean mummy.

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.

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," added Backwell, whose findings appeared online January 31 in the Journal of Archaeological Science.

Not King of the Hill

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.

(Related photos: "Best Microscopic Images of 2008 Announced" [October 15, 2008].)

Modern brown hyenas are known to hunt baboons and other large mammals when they are rearing cubs, the researchers note.

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.

The finding is a reminder that humans and our relatives were "lower on the food chain than we are at present," paleoanthropologist Randall Susman of Stony Brook University in New York State said in an email.

"Our early progenitors 200,000 years ago were just another element of the fauna, rather than the king of the hill," said Susman, who was not involved in the new study.

(See a human evolution time line.)

The hairs in this particular coprolite did not yield any DNA, Backwell said. 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.

Pat Shipman, a paleoanthropologist at Pennsylvania State University who did not participate in this study, agreed.

"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," she said.

"This could give us more evidence to answer questions being debated these days on how and when and where and why modern humans arose."

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