Homo Heidelbergensis replaced Homo Habilis about 1.5 million years ago.
Homo Neanderthalensis replaced Homo Heidelbergensis about 0.5 million years ago.
Modern humans overlapped with Homo Neanderthalensis for about 100,000 years.
Bruce Hardy counters the caricatures of Neanderthals by analyzing microscopic residues on stone tools - and making remarkable discoveries.
Story by Dan Laskin, photos by Jodi Miller
Bruce Hardy knows his way around a prehistoric stone scraper as well as a state-of-the-art digital microscope — and both are key tools in his research on humanity’s mysterious, often maligned cousins, the Neanderthals.
The Kenyon professor of anthropology is one of perhaps a hundred researchers worldwide who, working with scant evidence from archaeological sites mainly in Europe, try to deduce how the Neanderthals lived and why they vanished around 35,000 years ago, when modern humans appeared on the continent. Hardy himself has emerged as a leading expert in the painstaking technique of analyzing microscopic residues on stone tools.
It’s highly significant work. Based on residue analysis along with the wear patterns on tools, he and his collaborators have shown that Neanderthals — long considered slow-witted hunters who couldn’t do much more than bring down big game — were, in fact, skilled, adaptable foragers who likely had the ability to capture fish, birds and rabbits, who ate plants as well as meat, who worked with wood, and who may well have known how to make string, opening the possibility that they had snares, nets and traps.
For Hardy, the questions surrounding Neanderthals have provided not only an endlessly fascinating research agenda but also a field for passionate advocacy. The persistent image of Neanderthals as clumsy “losers” in the evolutionary game, he feels, offers a widely relevant lesson in one of the nastier aspects of human nature.
“Neanderthals are kind of the ultimate other,” Hardy said. In his view, too many scientists have ignored, distorted or simply failed to look for evidence that would undercut their assumption of modern humans’ superiority. It’s the kind of close-mindedness, he contends, that “plays out over and over again in prejudice and discrimination” through human history. Caricatures of Neanderthals, for example, unnervingly resemble the stereotypes of African Americans that justified slavery and lasted well into the 20th century.
Neanderthals are often defined by their extinction. Because they went extinct, they must have been doing something wrong."
Hardy’s personal evolution took him from a boyhood interest in archaeology to Emory University, where he majored in anthropology and French. By the time he started graduate school at Indiana University in 1988, he had studied early human fossils at the prominent Koobi Fora Field School in northern Kenya and spent a summer excavating at La Quina, a Neanderthal site not far from Bordeaux, France.
Hardy received his doctorate in paleoanthropology, the study of the origins and development of early humans, using fossils and other remains. At Indiana, he intended to focus on humanity’s earliest ancestors in East Africa, but funding problems led him back to the Neanderthals, and he wrote his dissertation about La Quina.
Neanderthals, who flourished for some 200,000 years, get their name from the Neander Valley, near Düsseldorf, Germany, where their first skeletal remains were found in 1856. Remains and artifacts have since been unearthed at thousands of sites in western and central Europe and parts of northern and western Asia. Scientists have found bones from more than 400 individuals.
The Neanderthals were shorter and stockier than modern humans, with large eye sockets, big noses and larger craniums: Their brains were just as large as ours, often larger. They share more than 99.5 percent of their DNA with modern humans. And while some scientists consider them a distinct species — Homo neanderthalensis — others point to evidence of interbreeding, with fertile offspring, making them a subspecies, Homo sapiens neanderthalensis.
The latest DNA evidence shows that “there’s been interbreeding in multiple places, at multiple times, between modern humans and Neanderthals,” Hardy said. “By most estimates right now, if you’re not from Africa originally, you’ve probably got between 2 and 5 percent Neanderthal DNA.”
Many of the debates in the field — the issues that rile Hardy — involve how these people lived and what they were actually capable of doing. The idea that Neanderthals were big game hunters who ate almost nothing but meat, and who lacked the ability to exploit a wider range of resources, reflects the fact that the most conspicuous food-related artifacts discovered at Neanderthal sites are the bones of animals like bison and deer, with cut marks indicating they were butchered. Since no other food artifacts appear, they must not have eaten anything else.
Similarly, the lack of bone needles at these sites has led some to conclude that Neanderthals could drape furs over their bodies but couldn’t make clothes.
What exasperates Hardy about this reasoning is its failure to consider evidence that is not as conspicuous or that has disappeared because it was more perishable than bones. And in the absence of evidence, preconceptions take over. “Neanderthals are often defined by their extinction,” he and a co-author wrote in a journal article in 2011. “Because they went extinct, they must have been doing something wrong.”
Hardy regularly has students in his “Neanderthals” course read a polemical article by John D. Speth, an emeritus anthropology professor and museum curator at the University of Michigan. “We have convicted Neanderthals of ‘gross mental incompetence,’” Speth wrote, “almost entirely on the basis of negative or missing evidence.” Hardy likes to point out: “The absence of evidence is not evidence of absence.”
It is in this realm — of invisible, or nearly invisible, evidence — that Hardy has made his biggest contribution. Two years after joining the Kenyon faculty in 2004, a conference presentation that he gave drew the attention of Marie-Hélène Moncel, an archaeologist with the National Museum of Natural History in Paris. She was overseeing excavations in Payre, a Neanderthal site in the Rhône Valley of France where artifacts date from 125,000 to 250,000 years ago.
She invited Hardy to collaborate, and he has been working with her and a network of other European scientists ever since, analyzing artifacts from Payre and elsewhere. When he travels to France, as he did this past summer, he often spends 10 hours a day at the microscope, peering at prehistoric stone tools.
Hardy has done some work in use-wear analysis, noting wear patterns on the tools that indicate they were used for scraping hide, processing meat, or working on reeds, grasses or wood, for example. He has also found evidence of hafting — the use of handles or straps with the tools.
But he devotes most of his research to residue analysis. In this area, “Bruce is a leading figure,” wrote his Kenyon anthropology colleague Edward Schortman, “and the results he has produced are truly astounding.”
Hardy and his collaborators have found the remains of hair, feathers, starch grains, plant tissue and animals including fish, ducks and rabbits. They’ve also found bits of wood along with twisted fibers — the latter suggest the making of string.
These discoveries support a picture of Neanderthals as people with detailed knowledge of their surroundings who, adapting to different environments, captured agile small prey, exploited a range of plant species, and made tool handles and string. They caught both fish and birds — activities that are “often used as markers of modern human behavior,” as one of Hardy’s co-authored articles puts it.
Hardy’s work has brought new attention to perishable materials and what they might reveal. Although he uses automated microscopes that create 3-D images and, sometimes, scanning electron microscopes, he still relies extensively on reflective light microscopy — old technology that earlier researchers could easily have used to examine residues. But most scientists simply weren’t interested. In fact, until the 1980s, archaeologists routinely washed newly discovered tools in chemical solutions so that they could eliminate the organic materials and more easily see the wear patterns.
Few people have expertise in residue analysis because, as Hardy said, “you have to know the microscopic anatomy of a whole bunch of different plants and animals, roots and tubers; you’ve got to know how to identify hair and feathers and fish scales.” He studied for a summer in Australia under Thomas Loy, a pioneer in the field (who died in 2005), and then continued to experiment and learn on his own.
Part of the learning process is play of a sort: You use facsimile stone tools as a Neanderthal might, see what the residues look like and compare them to what appears on tools from actual prehistoric sites. Hardy has worked with Kenyon student researchers to “build up a larger comparative collection of modern material that I can then look for archaeologically,” he said.
The results [Hardy] has produced are truly astounding."
Edward Schortman, J. Kenneth Smail Professor of Anthropology
Rebecca Stewart ’09 (formerly Rebecca Warren), for example, completed an honors project in which she butchered fish with stone tools and described the microscopic residues in detail. Hardy actually discovered prehistoric residues matching Warren’s, and in a 2011 journal article, he and Moncel cited Warren’s thesis as providing “new criteria for recognizing fish exploitation in the archaeological record.”
This past summer, Clay Whiteheart ’18 worked with Hardy as a summer science scholar, investigating the possibility that Neanderthals could have made more complex clothing by “sewing” with perishable materials like thorns. The research goes to a vital issue: Sewn clothing, as opposed to draped fur, is considered essential for thermal regulation and thus survival, so if the Neanderthals couldn’t sew clothing (because they didn’t make bone needles), how did they survive for 200,000 years?
How indeed? And why did they become extinct? Theories on the group’s disappearance abound. Maybe modern humans occupied the same niche and outcompeted them, or introduced diseases that the Neanderthals couldn’t handle. Maybe climate change killed them off.
Dissatisfied with single-cause explanations, Hardy surmises that multiple factors played a role. “You can have something relatively benign, like a slight difference in fertility over time. Modern humans are having more kids and you get demographic swamping; one out-populates the other.”
But the shared DNA and evidence for interbreeding suggests something else. “At some level, we’re not really talking about an extinction,” Hardy said. “We’re talking about an assimilation, where part of the Neanderthal genome is brought into the modern human.”
The ultimate other may not be so different after all.