Science Friday - Anthropologists Have A Bone To Pick With New Skull Finding

Episode Date: October 3, 2025

There’s fresh drama in the field of human origins! A new analysis of an ancient hominid skull from China challenges what we thought we knew about our ancestral family tree, and its timeline—at least according to the researchers who wrote the paper. The new study claims that Homo sapiens, and some of our relatives, could have emerged at least half a million years earlier than we thought. But big claims require big evidence.Anthropologist John Hawks joins Host Flora Lichtman to piece together the details.Guest: Dr. John Hawks is an anthropologist and professor at the University of Wisconsin-Madison.Transcripts for each episode are available within 1-3 days at sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Hey, this is Flor Lixman, and you're listening to Science Friday. Today in the show, new skull just dropped. An ancient hominid fossil from China is shaking up the human origins field. This is really a case where if you have another piece of evidence, it might be a good time to sort of show people. A new analysis of a very old skull challenges what we thought we knew about our ancestral family tree and its timeline. At least according to the researchers who wrote the paper, the study in the journal science claims, that homo sapiens and some of our relatives could have emerged at least a half a million years earlier than we thought. But as we know, big claims require big evidence. So here to piece

together the details is Dr. John Hawks, an anthropologist and professor at the University of Wisconsin Madison. He studies the bones and genes of ancient humans. John, welcome back to Science Friday. Hey, thanks for having me. First of all, is it drama in your field right now? You know, look, I'm a field that's got a lot of drama in it, but I will say that this is a really astounding claim and one that has, you know, drawn a lot of attention to the question of whether we know as much as we thought we did about our recent past. Okay, let's talk about the study. I know it centers on this very crushed up skull. Tell us about it. Yes.

So this site in central China, widely known as a Yunshan site, is a site where in 1982, two partial skulls were found, and they were both highly crushed. That makes them tough for us to study, obviously, but they have features that connect them with an early species in our ancestry known as Homo erectus. The new study has created a reconstruction of one of those skulls that tries to put it back into its anatomical order

so that we can see more about its anatomy and therefore its relationships with us and with other hominence. And their claim is that this is actually not a Homo erectus. It's actually something that's closer related to us and related to some more recent skulls from China, skulls that in recent years have been called Homo Longhi. And so the idea is that this lineage of hominins is something that evolved in China maybe before a million years ago and existed much later than that in China until at least 200,000 years ago or later. The interesting piece of that is that this lineage, we have DNA from the most recent part of the lineage.

And that DNA connects them with a group that we know as the Denisovans, a group that is really important in our ancestry because they are among the ancestors of today's people. So was there DNA from this skull? No, there's no DNA from this skull from Yunshan. And in fact, at around a million years old, it's a, you know, it's very much a long shot. that there would be DNA evidence from this very ancient time. Is the main takeaway here that this skull looks different and actually more modern than we thought it should? Yeah, the story of the research is that this skull is more advanced than we thought it should look at a million years ago. It has a larger brain. It has a more rounded skull. It resembles some of the later skulls.

And so the idea is that maybe this more modern form had already appeared before a million years ago. You know, where the interest is for anthropologists like me is that we have a genetic timeline. We've got DNA from some ancient fossils. Those include the Denisovans and the Neanderthals. And those are all later fossils. Those are all fossils that existed within the last 150 to 200,000 years that we have DNA. but we can use that DNA to reconstruct their tree. The tree of relationships of those lineages,

the Neanderthals, largely in Western Eurasia, the Denisovans, largely in Eastern Eurasia, and African ancestors of ours, modern humans in Africa, those branches we estimate from DNA go back around 750,000 years ago. So a skull like this, if it belonged to the Denisovan branch, would suggest that our timeline was wrong, that maybe the DNA is giving us the wrong picture about how long ago our ancestors arose. And that throws into question a lot of things that we estimate from DNA. I'm going to take a wild guess that not everybody in the anthropology world is

on board with these conclusions. Yeah, somebody like me, I study DNA and I study ancient fossils. And I've got to tell you that ancient fossils can look similar for lots of reasons. Their environments could be similar. They have similar adaptations because natural selection has affected their populations. DNA has got 3 billion base pairs of genome that we can compare between different individuals and different populations. And that's a lot of information. We have a lot of knowledge today about the tree of these populations from DNA. And so it would take a really, really convincing set of evidence for me to go and say, you know what?

I think that that Denisovan DNA, we got it wrong. I just, I'm not there with this evidence. What would be a convincing amount of evidence? Like another skull? You know, the really interesting thing about this site is that there is a third skull that was discovered a few years ago and is still in the process of being studied. We know that it's there, but we can't see it yet. And the folks who are working on it, I'm sure they're doing great work on it,

but this is really a case where if you have another piece of evidence, it might be a good time to sort of show people, hey, we've got more than just this skull that we rebuilt. We actually have a set of evidence that is making us, it's reinforcing our new point of view. our anthropologists like, release that skull. You know, that's sort of my attitude. I always feel like our conclusions are the strongest when we can share the data with everybody.

And in a lot of cases, we're not there. You know, countries have different models of how people work on their fossil remains. They don't release things as openly. And I am always advocating for a vastly more open release of things. If we can see the stuff, we're in the United States. States and in many other parts of the world are facing a lot of doubt about evolutionary science. And one reason for that is that the evidence isn't just there for everybody to see. I want you to put this finding in context.

I mean, it seems to me, just from covering this, that the ancient human family tree has been in major flux, you know, for the last decade or two. New branches, new intersections. Can you give me the sort of 10,000-foot view of the field? Absolutely. Over the last 15 years, we've acquired this ancient DNA record of the later parts of our evolution. And throughout the earlier parts, going back to as early as 7 million years, we've found new fossils that give light to new branches that we didn't suspect had existed. We have unexpected branches in South Africa, the species that I was involved in helping discover.

Homo Noletti, that is really different from today's people, but existed until 250,000 years ago or less. So it existed when our species arose. The Neanderthals and Denisovans, we now know, contributed DNA to our lineage, to our line, modern humans, and that suggests a network of connections. So we're looking at a tangled web of relationships going back in time with some new members of our family that we didn't suspect had existed, but also new connections between some of the old ones. I mean, this must be vastly different from when you began working in this field. You know, when I first started, we were still arguing about whether there had been ever more than one kind of human ancestor at a time, or whether the tree was filled out with more branches.

And today we're looking at dozens of branches, some of which reconnect over time and become part of our ancestry in different ways, and some of which go off in very different directions. We have a fossil diversity in our ancestry that nobody appreciated 30 or 40 years ago. You know, whenever we see headlines like this, you know, that this skull pushes back the timeline of human evolution or changes some relationship between. between ancient humans. You know, I think it raises the question of why, you know, why should we care about that? If something did evolve a couple hundred thousand years earlier than we thought, why is that a big deal? You know, I think that my answer to most people about that is that when you look around the world today, there's this tremendous diversity of people that you see, right?

People are different colors. They look different. They're different sizes. their hair is different. And we think of that as being really different. The fact is that people around the world everywhere today are more genetically similar than chimpanzees that live in neighboring groups in one small part

of the Democratic Republic of Congo. Is that true? Yeah, absolutely. And so you have what is today so low variation genetically, but very high variation in some respects, right? you look at people, they look different, and that can be confusing, right? How does this emerge? It emerges because our lineage is adapting rapidly to new landscapes, new environments, using the genetic heritage that we all share in different combinations.

Uncovering the ways that that has come to pass helps to inform us about our shared humanity, the fact that we're all the same everywhere, but also helps to inform us about our potential. As we move forward into the future, we're drawing upon our genetic variation that comes from such a limited number of ancestors in the past. And we're trying to learn how they lived so that we can think through how we can shift and change our lifestyles in the future. What do we need data-wise to definitively answer some of these questions about our past, about timeline, about family tree? You know, fascinating. The fascinating thing is that, you know, today, I can tell you the answer to questions that remained open for 150 years. I know that I have about 2% Neanderthal ancestry, and I know that because we have genetic

sequences from Neanderthals and whole genomes from me and many other people, and I can find the Neanderthal chunks. So one answer to your question, right, what more do we need is we got everything we needed and we answered some old questions. The problem is, of course, that that opens new questions. And that's the way science works, right? We've got a new telescope. We can see deeper into the past.

We see things we didn't see before. But in the same vein, it creates for us new problems. And we're working to solve those problems with new discoveries of the fossils. I mean, is it fossils? Does it come down to just, we need more fossils? We always need more fossils. I got to tell you, right? If somebody who has found a lot of fossils and has described a lot of fossils,

I have to say that what I've found and described is a drop in the bucket from what it would take to uncover some of the chapters of our past. Dr. John Hawks is an anthropologist at the University of Wisconsin-Madison. John, thanks for joining us today. Thank you. Today's episode was produced by D. Petersmith. But a lot of folks helped make this show happen every single week, including Annie Nero. Jason Rosenberg. Sandy Roberts.

Robin Casmer. I'm Flora Lichtman. Thanks for listening.