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Podcast: What do teeth and bones tell us about our ancestors?

What can the skeleton tell us about the lives of medieval people? How can teeth answer questions like where do people come from and where do they move to? Not only today but even hundreds of years ago. In this episode you’ll hear how VUB-scientists Veronica Jackson and Rachèl Spros find the answers to those questions and you’ll discover how migration happens nowadays.

Listen to this episode of 'Scientists with a cause' on Spotify, Apple Podcasts or Google Podcasts.


Bert: [00:00:10] Scientists With A Cause is a podcast in which you discover how and what VUB scientists contribute to the Sustainable Development Goals. Those are 17 goals agreed upon by the United Nations as a part of sustainable development and development coordination. How do they work? What goes on inside VUB? The scientists take their turn in this podcast to tell you about their cause.

Veronica: [00:00:35] The idea of people being forgotten, I think, is very sad, and I see it as a bit of an injustice.

Bert: [00:00:42] Veronica Jackson is a PhD student studying the effects of urbanization on the health of an archaeological population.

Rachel: [00:00:49] Mobility is something from all times. It's not something that only started like a few years ago. And you can really see that by just looking at the chemical composition of their bones [00:01:00] and teeth.

Bert: [00:01:00] Scientist Rachel Spros is researching mobility and it may be surprising, [00:01:04] but in a very interesting way. [00:01:06] And Florian Trauner shifts focus to more recent mobility.

Florian: [00:01:10] Up until today, the usual asylum system has always worked with individual assessments. With the Ukrainians, there was a departure from this approach and the EU said we grant protection to all Ukrainians as a group.

Bert: [00:01:24] This episode puts the focus on the SDG: peace, justice and institutions, from centuries ago.

Veronica: [00:01:30] We're looking at 1,200 skeletons from the city of Ieper, and they were buried from roughly the 12th century until the 16th century.

Bert: [00:01:40] To the big shifts and events we've experienced in Europe in the past ten years.

Florian: [00:01:45] What we could see is that state authorities have become a bit reluctant to engage, comprehensively, to invest a lot in this sector.

Bert: [00:01:55] From the past to the present and to the future of peace, justice and institutions. [00:02:00] In this episode of Scientists With A Cause.

Veronica: [00:02:15] It's finding out the stories of these people. Like each skeleton that I do is a different mystery to solve, sort of... That I've got the clues in the skeleton from what you can see. What we do is we construct a biological profile. It's called a biological profile because we are estimating biological characteristics of the individual, so, such as their biological sex, their age at death and their height. And with these, we can reconstruct the demographics of a passed population and look at the birth rate and the death rate. And that translates into population growth or population decline through a specific period of time. In life [00:03:00] bone is actually made of living tissue. It's hard because we're used to, like, Halloween skeletons and stuff, and so, we're used to them as being inanimate objects. But during life they are living tissues. So you can see that, for example, and if you break a bone, it will grow back together. Similarly, your bones record certain activities that you do throughout your life. So, an example of that could be activity induced arthritis. That's something a lot of people have. As the joint wears down and the bones start to rub together, it wears down the surface of the bone and it also grows a little bit of extra bone on the outside of the joint, which is why sometimes you can't fully extend, say, your fingers or something if you have severe arthritis.

Veronica: [00:03:43] And so in those ways we can look at, those as well as muscle attachments and stuff like that, to reconstruct a little bit how they physically interacted with their environments. The idea of people being forgotten I think is very sad and [00:04:00] I see it as a bit of an injustice, like the people who are remembered through history and the people whose stories get told over and over and over again versus the people that no one ever gives a second thought to. I had a child once who had a blunt force trauma on the forehead, which sounds very violent and it was fully healed. Sorry, I should rush to say that it had been fully healed, which means that this toddler probably ran into something, as toddlers often do, and had quite the bump on its forehead. And but it survived that. And so that's nice. And I found that to be a very illustrative example.

Bert: [00:04:37] It makes studying an archaeological population a lot more tangible and less distant through time. For Veronica Jackson, that population, as I said before, is a population discovered in Belgium.

Veronica: [00:04:49] We're looking at 1,200 skeletons from the city of Ieper. And they were buried from roughly the 12th century until the 16th century. Through [00:05:00] these, we hope to study the health of medieval people in an urban center, as well as the health consequences of urbanization. As is often the case in archaeology, the graveyard was discovered by accident, ahead of a construction project. They were building a residential building there. And by law, which is great, they have to conduct an archaeological survey ahead of time to make sure that while they're digging the foundations, they don't destroy anything. And in this case, it was very lucky because not only did they find something, they found hundreds of graves and much more than they were expecting when they first found them. So the first stage in analysis is laying them out and then we conduct an inventory to see how much has been preserved. And then we move on to constructing the biological profile and they're variously preserved. That often has to do with the soil that they're buried in and the moisture and the acidity level. And so sometimes they're nice, solid bones [00:06:00] that, like, they could be very modern. And then also sometimes they're less beautiful. We can look at diseases through time and the effects of urbanization. And so the UN currently thinks that more than half of the world population will live in cities by 2050. And so looking at the effects of living in such close proximity to one another and possibly worse air quality and stuff like that can influence modern conceptions of urbanization and the use of it. Also, potentially, we haven't had it in this collection yet, but you can look at the evolution of a disease over time because in modern clinical studies it's impossible to get such a big population to study, a study sample, as well as a population who has suffered from a wide array of diseases without seeking medical attention. So in the past we can see the full expression of tuberculosis, whereas [00:07:00] in modern contexts most people would seek out medical intervention and we wouldn't be able to see the full trajectory of the disease.

Bert: [00:07:14] So Bones can tell quite a story if you're looking for the right things. Archaeological scientist Rachel Spros is involved in the make-up of the city project. Even from a young age, she knew she wanted to end up in archaeology.

Rachel: [00:07:32] I grew up with Indiana Jones and I always knew like: I want to be an archaeologist. And it faded away when I became older because I also had the I also had people telling me like, oh, what do you want to do with archaeology? What's the use of that? What's the point? But then when I got older, after high school, it's like, yeah, there is a point in archaeology. I work with isotope, stable isotope. So I look at the chemical composition of the bones and, more particularly, specific isotopes from one or more elements. So [00:08:00] I look at different things. I look more at mobility, at diet. So it's more complementary. Everything we eat is made up out of elements, and the moment we eat them, we incorporate them and our bodies use it to build up our skeleton. We can get a signal of what they actually ate. Bones, they remodel, but they take a long time to remodel. For example, the femur, your upper leg, it takes about 15 years to remodel. So we get a general idea of what people ate during 15 years so we can see if they ate fish, if they ate meat, if they were vegetarians, vegans. Today, being a vegetarian is... It's a choice. We choose to be vegetarian. We choose to be vegan. Back then, it wasn't that much of a choice. It was more...

Florian: [00:08:49] If you can afford it or not.

Rachel: [00:08:50] Yeah, exactly. And the same with fish. Usually if we find people that were vegan or vegetarian, they usually didn't have the money [00:09:00] to get those type of foods. So we know that they were not as wealthy and sometimes we can see it. Veronica can see diseases that are linked to malnutrition and we can see it in the bones as well. So they were probably not as healthy as you can be today, as a vegan or vegetarian. It really depends on where you live because people who live close to the sea, they have more access to marine foods than people that live very far inland. So if you live close to the sea and you had a high input of marine products like fish, seaweeds, things like that, you probably weren't that highborn. Whereas if you live inland and you have a lot of marine food, it basically meant that the fish had to travel to the place where you live and then you had to buy it.

Bert: [00:09:47] It may sound a somewhat tedious research, but for Veronica Jackson, the research can turn into something very real.

Veronica: [00:09:54] I occasionally get emotional when you really see a direct link to that person's life. [00:10:00] And so, for example, I had an individual from Breda and the burial context there made it so that his hair survived as well as his bones, but he had a mustache and some armpit hair and like all of the hair and yeah, that felt very personal and that really made me have a bit of an emotional reaction of like, oh, like I, I see you. I know you,sort of. These people, they might have been buried in marked graves at the time, but the grave markers have disappeared and so their names don't survive. We don't know what they did. We don't know anything about them. And through osteoarchaeology, we can sort of bring them back to life a little bit because we can learn about their lives that otherwise would be entirely forgotten. So I would say that you would have to be comfortable with that in the first place.

Florian: [00:10:53] Where you did you learn this?

Veronica: [00:10:55] A lot of my family members died while I was a child and stuff, and so just becoming comfortable with [00:11:00] the idea of death, not necessarily their skeletons or something, it's never been as jarring for me as I see it with other people who come into the lab or stuff like that.

Rachel: [00:11:11] The one thing that I like the most is migration. I think migration is still a big topic that is discussed today. And the fun thing about looking at people from the past is that mobility is something from all times. It's not something that only started like a few years ago. And not just from within Belgium, but from across Europe, across the world, people are moving around and we can really see that by just looking at [00:11:38] the chemical composition of their bones and teeth.

Bert: [00:11:40] Really?

Rachel: [00:11:42] Yes.

Bert: [00:11:42] So then you can see this person. He lived in Spain, but now he he died in Ieper.

Rachel: [00:11:48] Jup. Yes. So the teeth develop at a very young age and they no longer change. So what Veronica just explained is that the bone they will remodel throughout your life, but the teeth they don't. [00:12:00] So I look at the teeth to see where someone was born and where they lived during the first 15 years of their lives. And then I compare it with the bones to see if they moved around before they eventually died where they were buried. And that way I can track mobility. I think, especially what I'm looking at, what I want people to know today is that borders weren't always what they are today. We know that there have been borders in the past. We learn it in history, but it wasn't so much of a problem to cross them as it is today. There wasn't so much of a hatred towards foreigners as we have today. And I think that's a very important lesson that we should learn from the past.

Bert: [00:12:46] Humanity created those borders. Borders that were not around before in history, even though mobility and migration have always existed. Florian Trauner is a political scientist and co-directs the Centre for Migration, [00:13:00] Diversity and Justice at the Brussels School of Governance. He confirms what Rachel Spross says about borders and takes you through the history of migration.

Florian: [00:13:11] Migration has always been part of human history and for a very long time, indeed, there were no borders at all. So the Homo sapiens started to spread across Europe around 40,000 years ago and took around 15 to 20,000 years really in Europe to be colonizing the whole territory. Migration continued to occur, but then it started to be more triggered by military invasions or military adventures. Slavic migration, the Islamic conquest of Europe. Or we had also examples such as the Vikings. We had this kind of migratory movements and then, later on, we can see that Europe, Europeans started to emigrate at a larger [00:14:00] scale too. So right now we are talking 15 to 16th century when there was the wars of religions and many Europeans started to leave Europe for America. 60 to 65 million people leaving Europe between the 15th century and the mid-20th century. Then we move already to the modern times where migration dynamics changed considerably and we had, again, much more immigration to Europe. But historically speaking, if you look back, I mean, in the history of Europe, Europe was a very important continent of origin, so to speak, really, really sent our our people all over the world. And it was Europeans who settled the American continent and made the wars, genocide also with the native populations there. But this is something very important to consider also when we talk about migration nowadays.

Bert: [00:14:54] Mm hmm. So shifting to current times, what situation are we in?

Florian: [00:15:00] If [00:15:00] you look in Europe post World War Two, we can see again different patterns of emigration and immigration. So, in the immediate post-war period, we had an economy that was growing again in Europe. We needed workforce. So a lot of people were hired either, for instance in Belgium, either from Southern Europe, Italy, Spain or from Morocco. In Germany we had considerable [00:15:28] 'Gastarbeiterprogramms,' [00:15:29] guest worker schemes for, for instance Turkey. So this was really important up until the oil shock of 73. Then this was really slowed down. Then there was a bit less of emigration. And then we started already to see the fall of the Berlin Wall, the implosion of the Soviet Union and East-West migration started to be more important. South-north immigration was not yet a big theme as it became in the in the later years. And [00:16:00] at the same time in Europe, they installed more and more this kind of free movement for workers. So we had very considerable movements between Europe and then there started to be more relevant numbers of migrants coming from outside territories as well, often triggered by wars. We had Afghan migrants in large numbers throughout the years. There was the Syrian refugee wave coming in particular in 2015, 2016. And right now we see a very considerable number of Ukrainians fleeing from the conflict.

Bert: [00:16:35] Looking at the numbers that are available, is this the largest human migration since World War Two?

Florian: [00:16:43] So in World War two, you had around 40 million people being displaced. So this is really a big number. Ukraine has a population of 44 million to give a comparison. So what was really striking difference is that so many people [00:17:00] left so quickly. So in World War Two, it took much longer and the biggest wave of displacement took place in the late days of the war, whereas in the Ukrainian conflict, large scale displacement took place basically from day one of the conflict. So this was really a big difference.

Bert: [00:17:21] A very visible and big wave of migration directly at the start of the conflict, with Europe opening its borders and welcoming those refugees into a safer place. Not only state authorities, but civilians as well, pressuring the authorities to do more and opening up their own homes to refugees. Even though research has shown that people generally think that migration numbers are higher than they actually are.

Florian: [00:17:50] In surveys, they often say: "We believe that 30 to 40% of our population has a foreign origin" but, de facto, it's much lower. So in most Western European [00:18:00] states, it's between 10 and 15%. Luxembourg is really the big exception. There, almost half of the population has a foreign origin. But for the rest of the Western states, it's between 10 to 15. Belgium: between 12 to 13%. And in Eastern European states, such as Croatia, Hungary, it's really just 1 or 2%. So here, immigration is lower than what many people believe it is, actually. What we could see is that state authorities have become a bit reluctant to engage, comprehensively, to invest a lot in this sector. So in principle, it's the state responsibility when refugees come in to take care of them. But we have seen that this is not always working so smoothly, so de facto, civil society actors, NGOs, they have played an increasing role in actually receiving the refugees. I mean, [00:19:00] sheltering, providing housing at the beginning. That's still mainly a state responsibility. But overall, civil society does play a role and an even increasing role and then a particularly important role if there is a huge influx of refugees coming in at once, as we have seen in the Syrian refugee crisis or with the Ukrainian displacement.

Bert: [00:19:24] When you say that that state authorities have been somewhat reluctant, maybe sometimes, I cannot help to think about a certain thing that politicians would say in those times that I just remember as being said: "If we do too much as state authorities, only more refugees will come here."

Florian: [00:19:42] But you're referring to the what is often called the pull factors. So there are the push factors and the pull factors. The push factors are the factors that make a person leave the home country. So it can be a lack of economic opportunities, but it can also be human [00:20:00] rights violation or persecution. And then there are the pull factors and the pull factors they are often seen: if a welfare system is too generous, then migrants may prefer going to the state that is actually offering this kind of benefits. So in Europe, and in particularly if you talk to the ministries of interior, they are very conscious about this pull factors and it's very big in their mind. There is a lot of debate if these pull factors are really so important. [00:20:30] Many academics, civil societies say the [00:20:32] push factors that the livelihood opportunities are so difficult or unbearable or there's war or whatever, that's much more important than whether there is, you know, 400 to €500 welfare scheme in Belgium or whatever, you know. But in ministers of interior, that's not a very valid argument. And in Europe in general, they try to harmonize these kind of benefits that refugees are supposed to get [00:21:00] in order not to make too much discrepancies between the states, so that migrants particularly could go to one state.

Bert: [00:21:19] Interesting information about the history of migration, the role of state authorities, and how they tried to organise migration among them in 2022. We, of course, see migration very clearly through the Ukrainian displacement, although it does not influence the total of human migration that much, according to Florian Trauner.

Florian: [00:21:40] The overall number of peoples migrating is not so much altering. So we talk about 3.6% of the world population that is actually migrating. So it's the 2020 numbers, but it has been relatively similar already in the fifties and sixties. So this overall [00:22:00] number is not too big. I mean, right now we have more people on the world, so absolute numbers are higher, but migration is relatively constant. But okay, this doesn't change that sometimes a particular region, a continent, is more affected by migration waves. As we have seen the Ukrainians, they are a bit dealt outside the usual asylum procedure. They are really considered as a group. Up until today the usual asylum system has always worked with individual assessments and authorities look on each person case by case if this person is being persecuted. This was even the case with relatively clear war refugees, such as the Syrians. But, even in the Syrian crisis, they always said: "We really look at each case." With the Ukrainians, there was a departure from this approach and the EU said: "We grant protection to all Ukrainians as a group." So they gave them a temporary protection for up to 3 years. They get a permit to stay. They get the [00:23:00] right to immediately work, the right to send their kids to school and to also get some subsidies. So this is a relatively important differentiation that is happening right now, that you have refugees from other world regions that continue to be individually assessed. And then there is a much more generous protection scheme for the Ukrainians.

Bert: [00:23:22] Why do you think that difference has now been made, to make that more collective protection?

Florian: [00:23:28] I think that there are different reasons. On the one hand, the war in Ukraine, the Russian invasion, really shocked Europeans. Many warnings were there, but it was not believed as very credible. And the war is so close by the European borders, so that the feeling of injustice vis-à-vis the Russian invasion has created a lot of solidarity with the Ukrainians. Many Europeans feel the Ukrainians are fighting a battle on behalf [00:24:00] of most of the continent. So if Russia gets away too easily, the government may continue aggression towards other states, coming closer and closer. And the third factor, this is discussed relatively widely also in the media, is whether or not it makes a difference that Ukrainians are white, are based in the Christian religion, which is a big difference to more recent other waves of refugees coming to Europe.

Bert: [00:24:29] Is that collective assessment for Ukrainians maybe unfair to Afghan and Syrian refugees?

Florian: [00:24:37] I think it's widely perceived by the communities of former refugee waves that the EU's generous schemes towards the Ukrainians is a bit unfair towards them. It's a political choice by governments that has been made. A big difference this time is, as well, that citizens at large really pushed governments to be more generous towards Ukrainians. [00:25:00] You had similar feelings in prior ways with the Syrians, but I would say it was not such a widespread push by so many citizens than we have seen right now, which also makes a difference in how how governments and the EU as a whole reacted.

Bert: [00:25:18] And also it's difficult to pinpoint or prove a racist motive, but it's also very easy to understand that for other refugees it might feel like that.

Florian: [00:25:28] Definitely, definitely. That this racist motives have been really widely debated immediately after the invasion of Russia. It has been reinforced by numerous stories that border guards in Poland, for instance, they let in Ukrainians very easily, but they refused to let in people with a different color, saying that they are not falling under this protection regime and should stay outside. So, in the end, the Polish government publicly stated that this is not [00:26:00] a formal policy and they want to let in everyone fleeing from the Russian invasion. But it has been really relatively credibly documented that this kind of practices did happen at the border.

Bert: [00:26:28] Will countries make more elaborate, concrete plans to to be prepared for similar events of migration in the future?

Florian: [00:26:36] The EU tried to reform its asylum and migration policy immediately after the migration crisis of 2015/ 2016. So right now we are in 2022. The reform has not been concluded. This just gives you an idea to how difficult it is for the EU, the 27 member states, to really come on a common understanding, common [00:27:00] policy in this field. So a big crisis always shows a need to be a bit more prepared, to not just react, but to really proactively plan what could happen. And then in the next crisis, and it's almost certain that other migration crisises will occur. It could be that the Ukrainian crisis is a game changer in the sense that Eastern Europeans were the group of states that were most reluctant to agree on any kind of solidarity and fair distribution of migrants in Europe. And right now, they are the states that are most exposed to the Ukrainian migrant wave. So they may see the position being shifted from being, you know, very opposed to being more a 'demandeur' of solidarity from the other member states. So this could lead to movement in the negotiations and the EU getting towards an asylum system, a migration system that is more comprehensive and better prepared. Bert: [00:28:01] This [00:28:00] was Scientists With A Cause, a podcast series of VUB, created by The Podcast Planet.


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