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Dr. Dawei “David” Han is a Postdoctoral Fellow in the Department of Biology at the University of Maryland, College Park. David received his bachelor’s degree in Biology from China Agricultural University and his master’s degree in Biology from Truman State University. He recently completed his PhD in Neuroscience at the University of Maryland, College Park where he is now conducting postdoctoral research. In this interview, he shares more about his life and science.
People Behind the Science Podcast Show Notes
Life Outside of Science (2:00)
When he’s not working, David enjoys taking care of his pet snakes at home and observing reptiles and amphibians in the wild in his backyard and local parks. There are a variety of snakes native to Maryland, and it’s fun to get outside and see what he can find.
The Scientific Side (3:34)
David studies how snakes hear. Snakes can detect sound without external ear structures, particularly low frequency vibrations, and David is interested in how this process works, as well as the structures and pathways involved.
A Dose of Motivation (5:23)
Learning more about snakes is something that David really loves to do, and this passion for his research questions keeps him motivated and inspired.
What Got You Hooked on Science? (9:21)
Looking back at old photos, David stumbled across one of himself when he was about five years old where he was posing with a large Burmese python at the zoo. This is about when his early fascination with snakes began. As a kid, he watched a lot of nature documentaries, and he was captivated by the animals they featured. David later began to realize that there was still so much about these animals that we don’t yet know, and he wanted to learn more. As an undergraduate student, David got involved in research, and he decided to pursue graduate school afterwards to continue answering the questions that interested him.
The Low Points: Failures and Challenges (17:04)
David’s PhD focused on how snakes detect vibration. To answer this question, David first had to better understand their central auditory pathways. What seemed like a straightforward project quickly became more complicated than he expected. The structures in the brains of snakes that are relevant for sensing sound and vibration are tiny and not exactly where he expected them to be, which made the project more difficult. While the tiny size of the reptilian inner ear was a big challenge, David managed to map every projection from the inner ear to the targets in the brain that they connected to. In doing so, they discovered that snakes and lizards use one of the organs involved in balance, the saccule, to sense vibrations. This led to a great paper that was recently published in Current Biology. The project ended up being more complex than David expected, but encouragement and help from his advisor and colleagues in the field really helped him along the way.
A Shining Success! (20:27)
When David started his PhD project on vibration detection, the snake auditory pathway hadn’t been mapped yet. This meant that he had to add dye to all of the different organs in the inner ear that were related to hearing and balance to see where information from these organs was going in the brain. One of the biggest wins from this project was the discovery that the saccule was involved in the process of hearing for snakes and lizards. David has been following up on this new finding with some additional studies to determine if there are any other parts of the auditory pathway that could have been missed, and this is exciting work in progress. When the paper was finally published, David celebrated by going out to a nice restaurant with his wife.
Book Recommendations (22:51)
How Snakes Work: Structure, Function and Behavior of the World’s Snakes by Harvey B. Lillywhite and Your Inner Fish: A Journey Into the 3.5-Billion-Year History of the Human Body by Neil Shubin
Most Treasured Travel (24:13)
During his master’s program, David had the opportunity to travel to Gothenburg, Sweden, to share their research on snake skin in an oral presentation at the Society for Experimental Biology’s Annual Conference. This was David’s first time traveling to Europe, and he and his wife stayed in a house boat on the river. While there, David also met up with some future collaborators, and it was a fantastic experience overall.
Quirky Traditions and Funny Memories (26:18)
In many larger labs, it may be rare for the principal investigator to be in the lab, doing their own experiments, and regularly engaging with lab members. David’s mentors over the years have led smaller labs and have been really hands-on with teaching him new techniques and doing their own research experiments. It was a regular occurrence for him to be working on his projects side-by-side with his research advisors in the lab. His mentors have always been there to help when he needed it, but they also gave him the freedom to pursue his own interests independently.
Advice For Us All (30:28)
If someone asks you a difficult question when you’re giving a presentation, you can make evidence-based speculations, but if you really don’t know the answer, admitting that you don’t know can prevent you from saying something embarrassing. Also, be perseverant. Science is difficult, but oftentimes, there is a light at the end of the tunnel. Finally, snakes are remarkable creatures. Through evolution, they are able to do amazing things like move on land without legs and hear without having ear drums.
Guest Bio
David’s research is mainly focused on understanding how reptiles sense vibrations. He is trained in neurophysiology and comparative neuroanatomy, but he is a herpetologist at heart. Herpetology is the study of amphibians and reptiles. Most recently, David and his Ph.D. advisor Dr. Catherine Carr discovered a hidden “vestibular” pathway for detecting vibrations in the tokay gecko, which has broad implications on the evolution of hearing. Outside of work, David tends to a small personal collection of pet snakes, and enjoys going hiking with his wife and seeking out herps (although he claims no expertise at this!).