Solving the mysteries of prehistoric blades

Ancient weapons are found to have specific functions in hunting

​ Cristen Jansson

Source - http://www.dailyuw.com/science/article_3edf2704-2287-11e8-b5d1-fb7fa957ae56.html

Ten thousand years ago, when humans went hunting, they had a multitude of tools and weapons at their disposal. The question is, which one did they use on what animal? Archaeologists have pondered the question for a long time and a recent study by UW alumna Janice Wood sought to answer that very question.

The remains of prehistoric weapons, primarily blades and arrowheads, found at archaeological sites in Alaska can be divided into three different classes. There are teardrop-shaped stone blades, bone blades, and a composite microblade, which is a mix of the two. 

“Archeologists for a long time, and to some extent still, imagine that these two different styles of hunting implements, the stone point versus the microblade point, are indicative of different groups of people,” said Ben Fitzhugh, a professor of anthropology at the UW and a co-author of the study. “Some people, including me, have wondered, ‘Could it be that these different technologies are used for different things?’”

Ben Marwick, an associate professor of anthropology at the UW who was not involved in the study, says that the archaeologists based their conclusions about the origins of these blades purely on logic. 

“A bone is a round, thin object, and if you sharpen it, you can penetrate very deeply into something,” Marwick said. “The stone point will have a different property because it’s wide and flat and so it can tear the flesh more, and the composite tool [microblade] is kind of jagged and bulky.”

The microblade may have come into existence as a better means of conserving stone, but another idea researchers proposed is that it might have made a more lethal wound, which means it was created specifically for hunting.

“Using a composite tool is much less risky, because if you [miss the animal]  or something bad happens, you can repair it, but if you just have a single stone point, the risk [of irreparable damage] is quite high,” Marwick said.

Microblades also require the use of less stone than a stone blade, and this would be especially helpful if the area the hunter-gatherers dwelled had very limited resources of these specific stones. 

“Stone is often hard to find especially if you have to move around a lot, so it’s good if you don’t have to use lots of stone,” Fitzhugh said.

However, the specific uses of the blades in hunting was not known for sure until Wood completed her experiment.

Old weapons in the modern age

For Janice Wood, pondering the specific uses of these two blade types all began when she took Ben Fitzhugh’s arctic archaeology class in Spring 2013. The unsolved historical puzzle intrigued her so much that she set out to answer the question once and for all. 

“Alaska is a mystery and no one can seem to figure out if there were different people using different tools, or if the same people were using the same tools only for different prey,” Wood said. “My question was, ‘How were these points different?’”

Since no studies have been conducted that focused solely on the wound ballistics of those certain points, archeologists just rely on their best educated guesses. Thus far, these have been less than satisfying for Fitzhugh and Wood.

“[Fitzhugh] said, ‘It’s time for an experiment,’ as a joke, not knowing that I kind of took that seriously,” Wood said. “I was enthralled with it; I had to do it.”

While she was an undergraduate, Wood spent two summers at Rimrock Draw Rockshelter in Oregon, where she conducted her initial pilot study. Since there was not enough data to make any definite conclusions, she redid the experiment after her graduation, moving to Fairbanks, Alaska, where the real work began.

For the study, Wood created ten of each type of blade — a stone blade, a composite microblade, and a bone point — all from scratch. She used obsidian to make the stone points, antler and obsidian for the composite points, and cow bones for the bone points.

She also had to acquire targets to aim her blades at. One target was a substance called ballistic jelly, which was used to gauge wound severity and penetration. The second was a reindeer carcass which was used to test the wound characteristics of the different points. 

In subzero temperatures, Wood used a maple recurve bow to shoot the points at the targets. 

However, setting up the study wasn’t without its challenges. It took many hours for Wood to create the 30 points and acquiring all the materials she need for the study. Finding a fresh reindeer carcass through the legal channels was no easy task either.

“Finding a reindeer for the carcass side of the experiment was difficult, and it almost didn’t happen,” Wood said. “At least ten times this project should have stopped, but you have to find other ways.”

The results show that the different points are better at making different types of wounds and are specialized for specific types of prey. Bone points are better at puncture wounds that target small prey or for spinal shock on larger animals. Stone points are good at making incision wounds, and are thus better for hunting animals with large amounts of soft muscle. Overall, the composite microblade points are effective at making lethal wounds that result in major bleeding.

“Each one has its own performance strengths, and therefore each one should be specific for each, for different prey in different seasons in different habitats,” Wood said.

Broader implications

Wood’s experiment confirmed what archaeologists had long thought about wound ballistics but never explicitly tested. Their academic guesses were confirmed by Wood’s recreations and simulated prehistoric hunts. Marwick said this paper proves “these different types of tool really have these properties when hunting.”

“It has huge implications because humans only started using microblades and other things about 20,000-25,000 years ago, in the upper Paleolithic in Europe and Central Asia, and they brought that with them when they came to North America,” Fitzhugh said.

“Although [the] focus was just on people in Alaska … I think it‘s relevance can go far beyond that,” Marwick said. “In Australia, for example, we also find bone points and composite tools and stone artifacts there, so it helps us to try to understand the role of those tools in people’s toolkits. It can [also] be relevant to understanding the first appearance of these tools in the whole history of human evolution.”

Wood learned a lot from persisting through with completing the study, saying that the best part of it was “the satisfaction that I contributed to science, to the body of knowledge, and that it will be there always.”

She says that hard work, persistence, and a strong drive are imperative for this type of exploratory science. She encourages anyone who has a dream to chase it, no matter what it takes.

“It’s determination and trying to find ways around [obstacles] that great things can be accomplished,” Wood said. “I encourage my UW family to go beyond what they think their limits are. Ask a lot of questions, and even if they say you can’t do it, find a way.”