The World Heritage Cradle of Humankind site has yielded another important archaeological find, with the discovery of what is very probably strands of ancient human hair in a fossilised piece of hyena dung - dating back to around 200 000 years ago.
The strands are the oldest examples of their kind, surpassing the previous oldest known specimens of human hair by 191 000 years. The latter were found on a 9 000-year-old Chinchorro mummy from Arica, Chile.
The Chinchorro culture was prevalent in northern Chile and southern Peru between 5 000 and 3 000 BC. Mummies from this epoch are the oldest examples of mummified human remains, much older than even the Egyptian mummies. However, the new find makes the hair from the Chinchorro mummies seem positively youthful.
The strands were found in a hyena latrine - typically used by a single animal - embedded within a fossilised clump of dung known as a coprolite. Appearing to the untrained eye to be nothing more than a group of round white rocks, the coprolites each measured roughly 2 cm in diameter.
The high calcium content in such biological objects, and the calcium-imbued drip from the cave roof, facilitated the fossilisation and preservation of the hairs. After carefully extracting the delicate specimens with tweezers, researchers placed them under an electron microscope. Scans revealed external wavy scale patterns that are characteristic of primates - these, and the size and shape of the hairs suggest that they are human in origin.
The hyena species in question is the brown hyena (Parahyaena brunnea), a canny opportunist that derives most of its nourishment from scavenging, although it has been known to occasionally hunt small mammals.
Although they consider it most likely that the animal stumbled upon its last meal, scientists have not ruled out the possibility that a hyena attack was the cause of death. Brown hyenas are found in the area still today.
The exciting discovery was made at Gladysvale Cave in Gauteng, located about 45km north-west of Johannesburg. The cave, which sits in the John Nash Nature Reserve within the boundaries of the Cradle of Humankind, has been a prolific source of fossilised specimens since the first fossil, that of a baboon, was found in 1946.
The complex consists of three underground caves containing a substantial amount of breccia - that is, a clastic (fragmentary) rock composed of angular gravel-size fragments in a matrix or cementing material. Sediments in the cave date from as ancient as three million years to as recent as 250 years ago.
Since 1946, thousands of fossils have been recovered from the Gladysvale deposits, both inside and outside the cave, including rare remains of hominids. The first hominid remains - two teeth of the early human species Australopithecus africanus - were discovered in 1991.
The famous fossils of the Taung Child and Mrs Ples are both fine examples of A. africanus. The good news for the scientific community is that there are still millions of ancient bones in place in the cave, waiting to be unearthed.
Paleoanthropologist Dr Lucinda Backwell of the School of Geosciences at the University of the Witwatersrand headed the study, together with a team of South African and international colleagues from Switzerland and the UK.
Their findings are due to be published shortly in the print version of the Journal of Archaeological Science, but for those who can't wait, the article has been available on the journal's website since 31 January 2009.
The owner of the hair has not yet been established but, said Backwell, the hyena dung falls within the period of existence in Africa of early species of humans such as Homo heidelbergensis. This period, which spans 195 000 to 257 000 years in the past, also saw the emergence of the first anatomically modern humans.
"The hairs could belong to either of them or, of course, to a species not yet recognised," explained Backwell.
Although there are no hairs from early human species to use for comparison, and DNA sampling from the hairs was not possible, there is a plethora of coprolite material in the cave. Further analysis of the fossilised dung may well lead to a better understanding of the environment in which our ancestors lived, and their interactions with the creatures around them.
The hairs are significant in a number of ways. They represent a soft tissue find from a period, said Backwell, which rarely even yields skeletal material.
Furthermore, commented biological anthropologist Pat Shipman of Penn State, "The hair is an especially exciting find because it raises the possibility that there are other coprolites with other hairs, which would give us a new and quite accurate means of looking at the composition of ancient animal communities."
Hyenas search for food in their immediate surroundings, she added, so at that time a human lived, or at least died, close to Gladysvale cave.
This also raises the possibility that at that time humans were preyed upon or scavenged by hyenas, or that they competed with them for food resources.