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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