photo: Joshua Franzos
He’s an internationally renowned paleontologist whose fossil discoveries have literally altered science’s view of how mammals originated and evolved; a Ph.D. from the University of California, Berkeley; a Harvard postdoctoral fellow; a recipient of the National Science Foundation’s CAREER Award and the Humboldt Research Award; an author of groundbreaking scientific papers, including two featured on the cover of Science; and the associate director for research at Carnegie Museum of Natural History. Yet this big-time scientist still speaks about his life’s work with the excitement of a wide-eyed kid. His voice grows particularly excited when he talks about the objects of his deep scientific affection: tiny mammals from the Age of Dinosaurs, with names like Fruitafossor windscheffeli and Hadrocodium wui. Zhe-Xi Luo (pronounced zek-see lo) says he was “trained in the stereotype that early mammals were suppressed by the dinosaurs, lived in the dark, crawled on the ground, and were unremarkable.” But he’s spent his career enthusiastically proving just the opposite.
Born in Beijing, China, Luo got his “lucky break” when he received a government scholarship to study at the University of California, Berkeley, Museum of Paleontology in 1983. It was an exciting time for Chinese scientists, who, after the end of China’s Cultural Revolution, could once again fully participate in scientific study with their peers around the world. Luo took full advantage, and in 1996 he would join the scientific staff at Carnegie Museum of Natural History, fertile ground for paleontologists. “I was hired by the grand dame of paleontology, Mary Dawson!” he says, proudly.
When did you become interested in science?
Both of my parents were engineers, and early on I was interested in electrical engineering—I was always fixing radios as a teenager. In those days in China, it was illegal to use a short-wave radio to listen to foreign radio broadcasts, since the government controlled media. But my radio was able to pick up Voice of America, which had fantastic Chinese programming. That was sort of the start of my interest in science, and in the outside world.
How did you choose paleontology as an area of study?
I got into the University of Nanjing at 19. It had a strong geology department with a paleontology major, so I was influenced by that. This was after the Cultural Revolution had ended in ’76, when the Chinese universities were rejuvenated, and I was among the first round of students who got admitted through normal examinations.
Why did you decide to focus on mammals in your research?
After college, I had a huge lucky break; I got a government scholarship to study in the United States, and that’s how I got into UC Berkeley. My graduate advisor is a leading expert in this area, and so is my postdoc advisor at Harvard. That was how I got into studying mammals. As we ourselves are mammals, it was something I was naturally interested in.
What was your first discovery?
I was in graduate school, and my advisor took us to eastern Montana for field work. Right around that time I was beginning to be interested in the ear structures of mammals. The second week in the field I found a piece of a fossil ear
bone from the Late Cretaceous Period (65 million years ago). It was entirely coincidental that I found that fossil, but it really helped me steer my research. That was in 1983—and I’m still studying the ear!
Why does the ear fascinate you?
It’s a very complex structure, and in evolutionary biology it is always a challenge for a scientist to figure out how a complex structure originated. And the ear is particularly interesting if you want to understand mammals.
Mammals are so different from all other vertebrates because our hearing adaptations are much broader and we also hear the higher frequencies that other vertebrates cannot. And, philosophically, it’s very interesting, too. A reason we are here is because our lineage survived. If, anywhere between 220 million years ago and the present day, that evolutionary chain had been broken, we wouldn’t be here. So the ear adaptation was essential for mammals to explore many different ecological niches, and survive.
What would you consider your most significant discovery?
In the sciences, you never get fully satisfied with what you have done, and that’s what keeps you going. But, I would say the discovery of the totally unexpected diversities of mammals—that has been the most interesting result of my research as a whole.
We’ve discovered that mammals that co-existed with dinosaurs have many, many diverse ecological adaptations. We found a mammalian swimmer. We found carnivores. And we found Fruitafosser, which is part of our mural in our Jurassic Atrium in Dinosaurs in Their Time, which managed to live a very interesting lifestyle. It’s this spectacular range of different specializations that has changed our view of what the earliest mammals were like.
Why does it take such a long time to “discover” what a fossil is?
Fossils are silent, and it takes a paleontologist to tell their story. When you find a piece of material evidence from the history of life, you really have to place it into a broader biological context. Our job is to find the specimen, but then find out what it means for larger science. And the discovery phase is never a single person’s work; you often go into field exploration with a team of different experts. Once you figure out whatever was uncovered in the field, it goes to a particular expert for study. Occasionally you might have that eureka moment. But in most cases, if it’s truly interesting, it will take some time and tedious work for someone to figure it out.
Is there anything new at the museum that you would like to see happen?
I would love to see the research side of our museum have a better integration with our sister institutions around the Pittsburgh area. And I just hope that scientific research continues to be a fundamental part of our mission, including caring for our collections. Research and collections are inseparable.
Is that a struggle for any collection-based museum?
It is. Even scientists and scholars in a research university always get the same question: Why do you do research? But people need to appreciate that research and education are linked. Without new knowledge from research, students would tend to receive mediocre educations.
My example of taking more than 10 years to figure out what Hadrocodium wui was (the oldest known relative to living mammals) … you can superficially say it was all research, but research is fundamentally about learning something new.