As It Happens

Why scientists tried — and failed — to make a knife out of frozen poop

A survival story in the 1998 book "Shadows in the Sun," inspired anthropologist Metin Eren to try to make a knife out of his own frozen feces.

Anthropologist Metin Eren reverse engineered a blade out of his feces to test a legendary survival story

An example of a 'hand-shaped' frozen poop knife. (Submitted by Metin Eren)

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A Canadian book inspired Metin Eren to become an anthropologist — and to fashion a knife out of his own feces.

When Eren first heard about Shadows in the Sun by Canadian anthropologist Wade Davis, there was one story in the book that stuck with him. It was about an Inuit man who, under extreme circumstances, managed to forge a sharp blade from his own frozen feces.

To Eren, it was fascinating. But was it feasible? Even under ideal circumstances, could you really fashion a functioning blade out of poop?

As It Happens host Carol Off spoke to Eren, an archeologist at Kent State University in Ohio, about his decision to finally put the heroic story to the test. The study was published in the Journal of Archeological Science: Reports

Here is part of their conversation.

First of all, can you just give us the gist of this story that Wade Davis tells in his book?

The story, basically, is that there was an Inuit man who is being forced to move off of his settlement, and his family took away his tools in order to convince him to come along with them.

He refused to move off of his homeland. So, in the midst of a winter gale, he defecated into his hands and he fashioned a knife from the frozen feces, using a spray of saliva.

Then, the story goes, that he killed a dog with that knife, used its rib cage as a sled, and used its hide to harness another dog, and he sped off into the night.

Wow. That's quite a story.

It is quite a story. And it's one that, I think, has captured the imagination of a lot of people, including myself.

When that book came out in 1998, I heard Wade Davis tell that same story to Diane Rehm on NPR's Diane Rehm Show.

And because I heard that story, I was inspired to go into anthropology. And, in fact, I still today have the tape cassette that I ordered from NPR of that Wade Davis interview.

The knives were frozen in dry ice and sharpened with a metal file. (Metin Eren)

But you decided to apply a lot of skepticism to this story. Why is that?

Little did I know that 20 years after the story came out, I would be co-director of an experimental archeology lab here at Kent State.

We regularly reproduce ancient technologies in order to reverse engineer them and figure out how they work.

And it was late last year that it just sort of hit me that this idea of a knife being fashioned from frozen human feces had never really been tested before.

And just, I think as any good scientist, we were curious.

You decided that in order to do it, you had to recreate conditions that might have been around this Inuit man and his decision to escape this way. So how did you go about doing that?

It's first important to note that no experiment is ever perfect and no experiment can ever perfectly replicate reality. But we did the best we could.

So what I did was for eight days, I went on a high-protein and high fatty acid diet, which is sort of consistent with an Arctic diet. 

And after a few days of that, I started producing the necessary test samples. We start freezing the samples, and to be honest, I was surprised at how hard frozen human feces could become.

During the course of an experiment, scientists start to see a pattern. They have intuition about the results and I started to wonder ... this may just work. We may be able to make a knife out of frozen human feces.

OK. So the story is that he fashioned this knife out of his frozen feces and then he proceeded to basically skin and disarticulate a dog that he used as a sled. So how did you reproduce that part of it?

What we wanted to do was give our knives the best possible chance to succeed.

We actually had dry ice with us. And so we were able to stick the knives into - 50 C dry ice to get these things really, really cold.

And then, in addition to that, we had a metal file and so we were able to sharpen these feces knives as best as we could.

And then what we did was we used refrigerated meat instead of a fresh kill because we thought a fresh kill on that story would be a warm thing that would potentially melt the knives. And we want to see if these knives could cut, so we used refrigerated meat.

So we really put in place variables that allowed these knives the best chance to succeed. It was a very conservative test.

When we went to use these frozen knives — it was like a brown crayon, unfortunately. It just left very nasty streaks on our meat and they didn't cut at all.

OK. So, what have you learned from this?

You can't really approach this study with anything other than a sense of humour.

But we did this for a reason. We know from countless studies over the last 100 years that Indigenous and prehistoric people have produced mind-blowing technologies, and just in very innovative ways, to solve problems.

And I think, in some ways, that's one reason why this story of a frozen knife made from feces was so widely adopted across the academic and public literature, because it fits that narrative.

The problem, though, is that once you have stories that are unsupported, supporting narratives and stances of any kind, then it becomes a slippery slope. And other stories that are unsupported can also then be used to support stances and narratives.

And then, once you're in that situation, you're in real trouble. Because then you can start using unsupported, non-evidence based stories to support narratives and stances that are harmful to society — racist ones, prejudice ones, and the like.

And so I think, at the end of the day, what this study does is it reaffirms the importance of evidence-based science.

Written by Chris Howden and John McGill. Interview produced by Chris Howden. Q&A has been edited for length and clarity.