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Dr. Catherine Emily Carr is a Distinguished University Professor in the Department of Biology at the University of Maryland, College Park. Catherine received her undergraduate training in Zoology with first class honors at the University of Cape Town, and she completed her M.A. degree in biology at the State University New York at Buffalo. She was awarded her Ph.D. in Neuroscience at the University of California, San Diego. Afterwards, Catherine conducted postdoctoral research at CalTech, and she served briefly on the faculty at the University of Rochester before joining the faculty at the University of Maryland in 1990. She has served as a course director and co-director at the Marine Biological Laboratory at Woods Hole and has served as President, Director, and a Trustee for the Glass Foundation. Catherine has received numerous awards and honors over the years, including an Alfred P. Sloan Research Fellowship and she was awarded the Humboldt Senior Research Prize twice. She is also a fellow of the American Association for the Advancement of Science, the Hanse-Wissenschaftskolleg, and the International Society for Neuroethology. She received an honorary doctorate degree from the University of Southern Denmark, and she was named Mentor of the Year in the Neuroscience and Cognitive Science Program at the University of Maryland. In this interview, she shares more about her life and science.
People Behind the Science Podcast Show Notes
Life Outside of Science (2:51)
Lately, Catherine has enjoyed spending her free time reading and doing volunteer work for the Maryland State Park system. As a volunteer she has been removing invasive species, like English ivy and Japanese honeysuckle, from her local parks in an effort to restore the native habitats.
The Scientific Side (3:58)
In the lab, Catherine is interested in understanding how animals perceive their environment. This work involves observing animal behavior in the field, as well as laboratory studies to try to understand the biology of how different fish, birds, and reptiles use their senses and their nervous systems to perceive the world around them. Much of Catherine’s recent work has focused on hearing and how animals use the sounds they perceive and produce.
A Dose of Motivation (5:17)
“[It’s] not so simple.” – Nobuo Suga
What Got You Hooked on Science? (10:11)
Catherine’s first career choice at the age of five was to drive trains. Not long afterwards though, she realized her love of biology. Catherine remembers asking for biology books for Christmas each year and being fascinated by insects in the garden. When she started college, she already knew that she wanted to be a biologist. While at the University of Cape Town, Catherine was mentored by outstanding scientists, and she learned more about how to carefully observe animals and do good research. Catherine studied weakly electric fish in graduate school and then pivoted to studying hearing and sound localization in her postdoctoral fellowship. This latter area of research truly captivated Catherine, and she has continued to study sound localization for the past few decades.
The Low Points: Failures and Challenges (21:09)
Catherine and her colleagues have been working on a project to better understand hearing and sound localization in the barking geckos that live in the Kalahari Desert. She originally thought they would be able to film interactions between male and female geckos by suspending a camera on a pole above their burrows. When a male gecko called, Catherine envisioned the females would orient towards the sound and make their way to the burrow. However, by the time they set up their experiments, the females already seemed to know where the burrows were, and the males seemed to already know where their competitors were. They were able to save the field season by observing how the geckos responded to previously recorded gecko calls, but it was a humbling experience to discover that these animals knew a lot more about their environment than Catherine and their colleagues gave them credit for.
A Shining Success! (23:32)
Working with graduate students and postdoctoral fellows is rewarding for Catherine, and there was a particular graduate student project that Catherine really enjoyed. The project aimed to provide insights into the evolution of hearing, and it focused on salamanders. The student examined the structure of the inner ear of salamanders and discovered they had sensory cells that could respond to sound, as well as sensory organs that could respond to balance. She looked at hundreds of species of salamanders that lived in different environments, including those that lived in fallen leaves on the ground and those that lived in caves. They suspected that the salamanders living in dark caves might depend more heavily on their hearing, and they found that these salamanders had the largest and best-developed regions of the inner ear related to hearing. This was an important discovery because, though these salamanders didn’t specialize in hearing, their research demonstrated that there was something for evolution to act on to impact their hearing. Next, the student performed a study that demonstrated that cave-dwelling salamanders also had the strongest sense of hearing, and that salamanders have directional hearing, where they can better hear sounds coming from some directions than others. These studies provide evidence that supports the possibility that hearing evolved as animals moved from water onto land through progressive improvements in sensitivity to sound.
Book Recommendations (30:52)
Gaining Ground: The Origin and Evolution of Tetrapods by Jennifer Clack, The Other Big Bang: The Story of Sex and Its Human Legacy Eric S. Haag
Most Treasured Travel (31:55)
When she was a graduate student, Catherine had the opportunity to do field work in Panama studying weakly electric fish. Carrying her recording equipment around the jungle to record the electrical signals from these fish was absolutely remarkable. Looking at a small stream in the forest, most people would have no idea that there was a diverse array of weakly electric fish swimming amongst the tree roots under the surface and signaling to each other. This was Catherine’s first visit to the tropics, and the biodiversity was amazing and very eye-opening for her.
Quirky Traditions and Funny Memories (37:17)
Collecting data on the barking geckos in the Kalahari was full of memorable moments. Catherine and her colleagues had to fend for themselves for the most part, and she was lucky that both of her collaborators were excellent chefs. To celebrate their first night with successful results where they observed the geckos orienting to sound in the wild, they used the last of their flour and made a large pie for dinner. The pie featured a small gecko-shaped pastry on top, and it was delicious.
Advice For Us All (40:31)
A lot of science is about failure, but you can learn from your failures. When things fail, take a break, go for a walk, think it over, and try again. Don’t give up. Also, it’s very important to find the right mentors and identify a problem that you think is worthwhile and are willing to work hard to solve.
Guest Bio
The brain uses time differences between the two ears to localize the sound. Catherine’s lab studies sound localization in birds and reptiles, especially the neural circuits and computations underlying interaural time differences (ITDs). She focuses on ITD detection as a model for how evolution acts on neural circuits. In barn owls, Catherine’s lab has shown that ITDs are translated into location in space in the brainstem. Detection of these time differences depends upon two mechanisms of general significance to neurobiology: delay lines and coincidence detection. Incoming axons form delay lines to create maps of ITD in an area of the brainstem called the nucleus laminaris. Their postsynaptic targets act as coincidence detectors and fire maximally when the interaural time difference is equal but opposite to the delay imposed by the afferent axons. Similar principles guide sound localization circuits in other reptiles. Current research in Catherine’s lab examines models of delay line-coincidence detector circuits, on the assembly of the map of sound localization during development, and on how such circuits evolve. All projects develop from initial behavioral observations into systems, cellular, and molecular levels of analysis. When she’s not doing science, Catherine loves to read and volunteer at nearby state parks, removing invasive plants.