Hairs that likely belonged to humans living 195,000 to 257,000 years ago in Africa have been identified in fossilized brown hyena dung, according to a new study that describes the first non-bony material in the early human fossil record.
Until now, the oldest known human hairs were from a 9,000-year-old Chinchorro mummy from Arica, northern Chile. This latest discovery, made at Gladysvale cave, South Africa, exceeds the mummy's age by about 200,000 years.
The findings, which have been accepted for publication in the Journal of Archaeological Science, further suggest that early humans faced tough competition from carnivores that either attacked the individuals outright, or scavenged on their dead.
From an archaeological standpoint, however, the toothy animal's meal was a scientific windfall, since meat-eater dung can make an effective hair preservative.
"The oldest known hairs (for all mammals) are found in carnivore feces, permafrost and amber," Lucinda Backwell, who led the study, told Discovery News.
"It is the high calcium content in hyena coprolites (fossilized dung), together with the calcium-rich drip from the cave roof, which facilitated the fossilization process at Gladysvale," added Backwell, a University of Witwatersrand paleontologist.
She and her team removed a 9.8-inch block of calcified hyena waste from a brown hyena latrine found in the cave. Such latrines are only used by one animal and are typically demarcated areas that measure about 6 feet round in size.
The researchers then extracted 40 hairs from a single coprolite using fine tweezers. Although amino acid analysis detected no protein, and DNA sampling was not possible, very high magnification revealed that the size and shape of the hairs, along with their distinct cuticular scale patterns, best matched those of human hair.
Ten fossils that tell the human taleBackwell said the date of the hyena waste "encompasses the known temporal range in Africa of archaic human species, such as Homo heidelbergensis and the emergence of the first anatomically modern humans."
"The hairs could belong to either of them or, of course, to someone not yet recognized," she added.
Since the hair's chemistry was transformed by the animal's digestive process, its natural pigmentation, and whether or not it was originally wavy or straight, cannot be determined at present.
Nevertheless, Randy Susman, a professor in the Department of Anatomical Sciences at Stony Brook University, told Discovery News that the new study "is very interesting for a number of reasons."
"First of all, the hair casts left in coprolites not only represent a very early occurrence of human hair, but they also document the fact that hominins were being consumed by hyenas," explained Susman.
Bernard Wood, a George Washington University anthropologist, echoed Susman's view, adding that the discovery plays out like a great mystery with surprising clues.
Wood said that, "in the spirit of Cluedo (a mystery crime fiction board game), the Backwell study shows that hyenas must be taken seriously as a possible perpetrator of this 'crime.'"
He added, "But instead of 'blood on their hands, they have been found guilty of having 'hair in their poop!'"
Backwell hopes future technological advances may shed greater light on what the person represented by the hair looked like, what the individual's overall state of health was before the hyena incident, and more.
© 2012 Discovery Channel