Anthropologists Have A Bone To Pick With New Skull Finding

FLORA LICHTMAN: Hey, this is Flora Lichtman, and you’re listening to Science Friday.

[MUSIC PLAYING]

Today in the show, new skull just dropped. An ancient hominid fossil from China is shaking up the human origins field.

JOHN HAWKS: This is really a case where if you have another piece of evidence, it might be a good time to show people.

FLORA LICHTMAN: 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 of 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 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.

JOHN HAWKS: Hey, thanks for having me.

FLORA LICHTMAN: First of all, is it drama in your field right now?

JOHN HAWKS: You know, look, I’m a field that that’s got a lot of drama in it. But I will say that this is a really astounding claim, and one that has drawn a lot of attention to the question of whether we know as much as we thought we did about our recent past.

FLORA LICHTMAN: OK, let’s talk about the study. It centers on this very crushed-up skull. Tell us about it.

JOHN HAWKS: Yes. So this site in Central China, widely known as the Yunshan Site, is a site where in 1982, 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 hominids. 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 longi.

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 as the Denisovans, a group that is really important in our ancestry because they are among the ancestors of today’s people.

FLORA LICHTMAN: So was there DNA from this skull?

JOHN HAWKS: No, there’s no DNA from this skull from Yunshan. And in fact, at around a million years old, it’s very much a long shot that there would be DNA evidence from this very ancient time.

FLORA LICHTMAN: Is the main takeaway here that this skull looks different and actually more modern than we thought it should?

JOHN HAWKS: 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.

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 150,000 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.

FLORA LICHTMAN: I’m going to take a wild guess that not everybody in the anthropology world is on board with these conclusions.

JOHN HAWKS: 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 three 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 Denisovan DNA, we got it wrong. I just– I’m not there with this evidence.

FLORA LICHTMAN: What would be a convincing amount of evidence? Like, another skull?

JOHN HAWKS: 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 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.

FLORA LICHTMAN: Are anthropologists like, release that skull!

JOHN HAWKS: 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. Countries have different models of how people work on their fossil remains. They don’t release things as openly.

And I’m always advocating for a vastly more open release of things. If we can see the stuff– we in the United 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.

FLORA LICHTMAN: 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 for the last decade or two. New branches, new intersections. Can you give me the sort of 10,000 foot view of the field?

JOHN HAWKS: 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 naledi, 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.

FLORA LICHTMAN: I mean, this must be vastly different from when you began working in this field.

JOHN HAWKS: 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.

FLORA LICHTMAN: Whenever we see headlines like this, this skull pushes back the timeline of human evolution or changes some relationship between ancient humans, I think it raises the question of why. Why should we care about that? If something did evolve 200,000 years earlier than we thought, why is that a big deal?

JOHN HAWKS: 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. 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.

FLORA LICHTMAN: Is that true?

JOHN HAWKS: Yeah, absolutely. And so you have what is, today, so low variation genetically, but very high variation in some respects. You look at people, they look different. And that can be confusing. 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 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.

FLORA LICHTMAN: What do we need, datawise, to definitively answer some of these questions about our past, about timeline, about family tree?

JOHN HAWKS: The fascinating thing is that 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, what more do we need, is we got everything we needed and we answered some old questions. The problem is, of course, 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 that 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.

FLORA LICHTMAN: I mean, is it fossils? Does it come down to just, we need more fossils?

JOHN HAWKS: We always need more fossils. I got to tell you, as 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.

FLORA LICHTMAN: Dr. John Hawks is an anthropologist at the University of Wisconsin-Madison. John, thanks for joining us today.

JOHN HAWKS: Thank you.

FLORA LICHTMAN: Today’s episode was produced by Dr. Peter Schmidt. But a lot of folks help make this show happen every single week, including–

ANNIE NERO: Annie Nero.

JASON ROSENBERG: Jason Rosenberg.

SANDY ROBERTS: Sandy Roberts.

ROBIN KASMER: Robin Kasmer.

FLORA LICHTMAN: I’m Flora Lichtman. Thanks for listening.

[MUSIC PLAYING]

Copyright © 2025 Science Friday Initiative. All rights reserved. Science Friday transcripts are produced on a tight deadline by 3Play Media. Fidelity to the original aired/published audio or video file might vary, and text might be updated or amended in the future. For the authoritative record of Science Friday’s programming, please visit the original aired/published recording. For terms of use and more information, visit our policies pages at http://www.sciencefriday.com/about/policies/