Our Hominid Ancestors Made and Used Tools
Pre-human artifacts: William & Mary archaeologist Neil Norman discusses a set of remarkably ancient stone tools that he brought back from a site on the Horn of Africa. Photo by Stephen Salpukas
by Joseph McClain
Neil Norman found the tools when he and Bruce Larson were walking down the local wadi, a usually dry watercourse that hadn’t moved much in a long, long time.
Seasonal rains would flood the usually dry stream, drowning animals and washing them downstream, creating what Norman calls “a buffet of rancid carrion.” Scavengers converged on the wadi, butchering the drowned animals with stone tools they constructed on the spot.
Norman found two of those tools on that one short walk, likely near where they were dropped by their makers as long as two and a half million years ago. The individuals who made and used those tools were hominids, primate ancestors of modern humans. Back in his lab at William & Mary, Norman holds up one of the artifacts he brought back from Africa.
“This is what is known as an Oldowan chopper. You can see that it is very crude,” he explained. “The toolmaker selected a river-rounded cobble and hit it with another rock around 14 times to make a cutting tool. Feel the sharpness of the edge!”
The edge is keen enough to make you handle it carefully. The worked piece of stone is astoundingly businesslike, considering how long the chopper was lying around what now is the nation of Djibouti, on the horn of Africa.
They’re Old... But How Old?
And there is some question about exactly how old the tools actually are. Norman identifies the two oldest pieces, both choppers, as Oldowan – up to 2.5 million years old. Larson doesn’t challenge Norman’s identification. In fact, he says he hopes the choppers could be proved to be Oldowan, but he waits for further research to bear out Norman’s interpretation.
Norman and Larson were working on a U.S. military institution in Djibouti. Norman is an associate professor of anthropology at W&M. Larson, a 2003 M.A. graduate of the department, is an anthropologist working with the U.S. Naval Facilities Engineering Command.
Larson explained that his job is to make sure that construction at military installations doesn’t destroy any material that might be important to a nation’s culture, history and people.
“Whenever the Navy does any kind of work on shore installations, stateside or outside the continental United States, I have been charged with making sure that we take into account historic resources, both above and below ground,” he said.
Larson had been working the installation for 12 years. As the base was formulating plans for expansion, he went out to do a pedestrian survey of the expansion site.
Reves Center Support
His pedestrian survey prompted Larson to invite Norman and two Ph.D. students in anthropology, Maddy Gunter and Hayden Bassett, to Djibouti to do more extensive work in the area slated for expansion. A faculty fellowship from W&M’s Reves Center for International Studies allowed Norman and the grad students to make the trip and to bring home some of the oldest tools in the world.
The context of the discovery makes dating these artifacts challenging. Carbon dating doesn’t work on rock, so stone artifacts are dated by the age of items found in the same matrix.
“If I found these with hominid fossils, they would be in The New York Times the next day,” Norman said. He added that very few museums have such tools in their collections. If Norman’s choppers are indeed Oldowan, they’re among the oldest manufactured items known.
“There are no stone tools that we know of that are older than Oldowan tools,” Norman said. “There is some speculation that wood might have been used before that, or bone. But those things don’t survive in the archaeological record.”
Archaeologists use the term “provenience” to describe the circumstances of an artifact’s location and situation at discovery. Norman’s finds had plusses and minuses in the provenience category. On the plus side, the choppers were found in a region rich in prehuman discoveries – just 700 miles from where the australopithecine Lucy was found.
But, Norman picked the choppers up right from the surface of the ground. The site was savannah long ago, but now is a rocky desert. The archaeologists found the area littered with artifacts representing the entire time span of humanity and pre-humanity.
“Immediately we started finding artifacts that dated from a million years ago, all the way up to the present,” Norman said. “There were Neolithic stone structures. There are pharaonic materials; this area had a trading relationship with Egypt. There are amphorae from the Mediterranean. This really was the crossroads of the world for quite some time.”
Norman returned to W&M with a number of stone tools representing various ages. In addition to the choppers, he found two Achulean hand axes, which were made 100,000 to a million years ago. He also brought back an awl and a scraper, each 500,000 to a million years old.
In the absence of dateable matrix, archaeologists rely on the style of manufacture to assign a tentative age to each piece, much as an appraiser does with an unprovenanced attic find on the Antiques Road Show.
“If you pull a pair of jeans from a drawer, and they have bell bottoms and a high waist, you start thinking about the Seventies,” Norman explained.
Norman explained that the tools were made on the spot, as needed. Over the millennia, tools show advancements in quality. Tool manufacture is a learned skill and archaeologists believe these choppers and hand axes are tangible evidence of the first glimmerings of culture.
The toolmakers were not thinking about culture. Norman says the tools gave our remote ancestors distinct advantages over their non-primate competitors in the nasty, brutish and short existence that was daily life eons ago. He picked up one of the choppers again to demonstrate.
“One of the parts of the animal that we can exploit – and that most others couldn’t – is the marrow, what’s inside the long bones,” he said. “It’s difficult, even for lions.”
Norman is holding the tools in trust for the government of Djibouti. The artifacts will be returned to Djibouti, but first Norman will run some tests, notably microscopic examination of the wear pattern on the edges.
The tests can provide insights on what the tools were used on, but are of little use in identifying the species of prehuman that used them. Not all hominids used tools. For instance, Norman notes that Lucy was probably not a tool user; her species, Australopithecus afarensis, predates the Oldowan-era hominids.
“Once you get into the Homo line, you are talking about people – well, individuals, let’s say – who are physically and genetically much closer to us than are australopithecenes,” he said.
Norman added that the appearance of Homo habilis – the hominid who knew how to make tools – is widely regarded as one of the real watershed moments in human evolution as well as stone tool use.
“Quite possibly, those are the individuals who made these tools,” he said. “There’s some debate about that.”
The site of the dig was popular real estate for a long time, as made evident by the timeline of artifacts found on the scene. Norman says they found the remains of a stone-age workshop that probably dates to 30- to 40,000 years ago, in the early days of behavioral modernity among modern humans.
“Someone had sat cross-legged near a hearth and made a stone tool,” he said. “And all the flakes from that tool were right there. It is really humbling to be surrounded by the residue of intelligent life, material that vastly predates the oldest artifacts in North America.”
