IRA FLATOW: This is Science Friday. I’m Ira Flatow. Who are the strongest women you know? Well, for pure strength odds are athletes like Serena Williams or Ronda Rousey come to mind. But if ever Serena and Rhonda had the chance to go up against a prehistoric woman from central Europe, our Neolithic contestant could have given these modern athletes a run for their money.

In a new study out this week in the journal Science Advances, researchers say that by examining the humerus bone of prehistoric women, they have concluded that prehistoric women wielded the upper arm strength of today’s elite athletes. So how did these women get so yoked? Well, with me to explain is my guest Sabrina Agarwal, Associate Professor of Anthropology, University of California, Berkeley. And just to note, she was not involved with the research but she’s certainly familiar with it. Dr. Agarwal, welcome to Science Friday.

SABRINA AGARWAL: Hi, Ira. Thanks for having me.

IRA FLATOW: So who were these women and how would they have gotten so strong that if they were alive today they could have beaten or matched our modern athletes?

SABRINA AGARWAL: So this study looked at women. They looked at human remains. They looked at the upper bones and the lower bones of the arms and limbs that were excavated from cemeteries all the way from the Neolithic– so like 5,000 years ago BC– to the medieval period, so about 800 years ago. So about 7,000 years of time, all from central Europe. So they were excavated from these different cemeteries. They looked at their bones, looking at them with what’s called CT scans.

And while we can’t tell exactly what activities they would have been doing, what it did show from the studies is that they were certainly doing very demanding manual labor that was repetitive and for long periods of time. And so these women looked even bigger than modern rowing women and elite athletes in terms of how big their upper arm humorous bones were. So the types of activities we know they probably were doing were things that related to food production. The study notes things like grinding, but also things in the field like plowing, tilling, harvesting, livestock, all those types of activity. So we don’t always know exactly what, but we certainly know that it would have been something they did for a long period of time over their life course.

IRA FLATOW: Now I know you’re a biological anthropologist. And that means, in English, that somebody who studies the morphology of ancient bones.

SABRINA AGARWAL: That’s right.

IRA FLATOW: And I want to know how you can tell them from the bones why these women were so strong.

SABRINA AGARWAL: Well skeletons and bones are really cool. We often think of them as being kind of these dried up things that we see in Halloween shops and things like that. But during life, the skeleton is actually really dynamic tissue. It’s like an organ. It behaves like an organ. And during life, your bones change their shape. They change their size, depending on things that you do, and your diet, and different types of activities.

And certain bones, particularly the ones in the limbs, the arms and the legs, have a very direct relationship with mechanical loading and activity. And so if you do a lot of activity, you get bigger muscles. And bigger muscles make stronger bones and change the shape of the bones. And so we can kind of indirectly study that the size and shape reflects the amount of activity that someone would have had. So it’s recorded in the skeleton long after death in ancient skeletons from all over the place.

IRA FLATOW: That’s quite interesting. I mean, so why are we only now, after all these years, as an anthropologist, finding out how strong these women were?

SABRINA AGARWAL: Well, I think part of it is that there’s a kind of persistent bias that we think of with males being the ones that traditionally did all of the manual work and all of the provisioning in early societies. And this idea goes back to even how we think about humans at the dawn of human origins, modern Homo sapiens. We often thought that modern humans maybe even started to walk and be bipedal because they needed to go and provide food for the females. It’s actually called a male provisioning theory.

And I think that these types of bias, that it’s males that did all of the manual work and females that basically stayed back and had lots of children persist all the way into what we think about happening at the transition to agriculture. And so this idea that males are the ones that are doing all of the major contributions was kind of the assumption that was held, even when we started to look at this period of the transition. We assume that the women were staying at home and having babies. And so, to some extent, no one really thought about looking at the females directly.

IRA FLATOW: Interesting. Do you have the same kind of growth in upper arm strength around men at this time too?

SABRINA AGARWAL: Well, this particular study didn’t compare directly the humerus of the males to the females. What they did find is that males over long periods of time, over this period of 7,000 years, tend to continue to have really robust lower limb bones. And they see a very clear pattern. And females don’t show the same pattern. So they often thought, well maybe females weren’t doing anything. And then when they looked at these arm bones, they realized whoa, they were really big. They’re even bigger than modern elite athletes. And the males were also be big, but the patterns tend to be different.

The same researchers have published work in other journals that have shown that the women look like– not only are they big, but they’re big in both arms, both the left and the right. And so it’s kind of repetitive motion that’s going on for long periods of time with both arms being involved, something they don’t see in the males. And this agrees with other studies that we’ve seen looking at gender differences in robustus in the Americas, the Near East, the Far East. We’ve also seen these types of gender patterns.

IRA FLATOW: And was this during a transition period to agriculture when this was happening?

SABRINA AGARWAL: This is around the time period. So the Neolithic starts about 7,000, 10,000 years ago. We see this transition around 10,000 years ago in the Levant and then various parts of the world where people are transitioned from being kind of hunting and foraging to starting to settle down into more agro-pastoral ways of living and having the economy. And so this is looking at bones from that time period all the way up until the point like 1,000 years ago, the medieval time period.

IRA FLATOW: So interesting. If you had only found, let’s say, the forearm bones, how would you know that they were from a woman’s skeleton and not a male skeleton? And could they have been mistaken in years gone by for being men’s bones?

SABRINA AGARWAL: Well, that’s an interesting question. So these skeletons were from bodies that had enough of the skeleton that they can determine age and sex. So they didn’t include just humori that were found by themselves. So they’re full kind of bodies or bodies that are complete enough to determine biological sex. We’re not able to determine biological sex with just one bone, like an arm bone. Even if a bone looks big, that’s not an indicative of, oh, that it’s a male or it’s a female. You have to look at a lot of other indicators, mostly in the pelvis, that tell you that the morphology is what’s likely to be a biological female.

IRA FLATOW: So I guess my point is we could have discovered bones from before that we thought were male bones were actually female bones, if they didn’t have the rest of the skeleton to look at.

SABRINA AGARWAL: Yeah. Absolutely. And often in the past, early biologic anthropologist or kind of philosophers or people that were kind of a hobbyist interest in bones would pick up a bone and see it was really big and say, oh, this one’s a male. Or pick up a really small bone that’s light, and say this one must be a female. So that was kind of some of the biases that were taken in, that women must be the weaker sex.

IRA FLATOW: Thickness by the biases are changing now?

SABRINA AGARWAL: I think absolutely. I think there’s a shift in the technology’s ability to study these types of things in living and past humans and skeletons. But there’s a lot more questions now related to women’s biology, women’s roles in the past, and trying to understand some of the behaviors that might be affecting both morphology and health.

IRA FLATOW: From this transition period, from hunter gathering societies to agricultural life, how would that have changed things for women and possibly the evolution of their bodies?

SABRINA AGARWAL: Yeah, that’s a good question. I mean, we certainly know that the transition wasn’t something that just happened overnight. It wasn’t like early human societies that were hunting and foraging said, OK, let’s settle down now and start growing crops. It took a long time for these crops to be successful, for this new kind of way of transitioning to farming economies to do well and be successful. And so they probably still did a little bit of hunting. They would have done a lot of foraging at the same time. And females would have been instrumental at doing this. They not only would have been able to stay in one location, they still would have, of course, been having children, a lot of them, and would have been having perhaps a larger number of children that we would have had, breast feeding these children for a large time. But they also would have been really instrumental in food production, in producing food and also kind of arts and crafts things like pottery or textiles.

IRA FLATOW: So where do you go with research? Now that you’ve published this about these bones, what’s the next thing that you’d like to know?

SABRINA AGARWAL: Yeah, I think this study really is exciting because it starts to be an exciting time for us to start thinking about some of the other questions that would be really interesting to understand. One of the things the study also shows is that while the upper arm bones are really strong, the lower limbs tend to show a lot of variability. There are some women that have really strong lower limbs, even stronger than modern athletes, even stronger than some of the men, and some that are not. So I’m really interested in why there is this variability. Is it possible that it relates to different labor roles, even within females or other groups? Maybe there’s different ethnic groups or status groups. Or maybe female changes in behavior change over the life course and not doing the same things when they’re young but when they’re old. And so trying to really understand some of these gender differences and division of roles and labor over time and how it intersects other variables along with gender, I think is really going to start being an exciting area of research.

IRA FLATOW: So what other kinds of bones would you like to find?

SABRINA AGARWAL: Well, I’m really interested in continuing to look at earlier human populations, but trying to look at some of this variability more closely. So this study was really wonderful in giving us a diachronic perspective changes are long periods of time. And I think what a lot of us researchers want to do is to look at some of these populations more closely. Try to look at the differences within groups, looking at the skeleton and different parts of the body. So not just bones that are mechanically loaded like the arms, the legs. But try to look at how the bone is responding in other places. Maybe the physiology or reproduction or diet and things like, and seeing how some of these variables intersect with bone morphology and health.

IRA FLATOW: Is there a bone collecting nirvana somewhere in the world that you’d like to get– is a good place to search for this stuff? Better than some other places?

SABRINA AGARWAL: Yes. I think archaeologists are fairly lucky that we often have sites that we’re able to study some of these things and cemeteries that are excavated and museums that curate long term collections. And I think one of the things that the study highlights is that we also have to have a good base of modern data on women’s bone to compare a lot of these results to. So before, even when we were looking at female data, we didn’t have kind of apples to apples to compare it to. And this study, by taking modern samples and looking at the bone morphology, we’re actually able to have more meaningful interpretations. I think of archaeological data.

IRA FLATOW: Can you just look at a bone like a regular person and not wonder about its origin and everyday life? Or is that your business? I can’t help myself.

SABRINA AGARWAL: Yeah. That’s kind of our business. I mean, I think certainly we always, when we look at these bones, do you think about the fact that they’re people. They’re people’s mothers. They’re people’s sisters. They’re people’s wives. And they’re doing things. And so I think the curiosity comes because we even when we look at one isolated bone, we’re very curious to find out what was it like to be this person, to be alive during their time period.

IRA FLATOW: I guess just the same thing about the dinosaur expert trying to eat a piece of chicken without thinking.

SABRINA AGARWAL: Yeah, absolutely.

IRA FLATOW: Sabrina Agarwal, Associate Professor of Anthropology at the University of California at Berkeley. She joins us via Skype. Thank you for taking time to be with us today.

SABRINA AGARWAL: Thank you. Thank you for having me.

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