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Ask-A-Scientist Podcast E7: Dr. Sarah Kienle, leopard seals researcher

Listen to our podcast episode or read the transcript below featuring Dr. Sarah Kienle, leopard seals researcher, as she talks to SJK about the differences between sexes, the best methods to sedate a napping seal, and studying marine animals while living in Texas.

“In California, it was really nice to be 20 minutes away from a breeding colony that you could go in the morning…”

“…seals on the beach in a food coma basically were snoring…”

“It’s almost as if males and females are different species and just come back to mate once a year.”

Tanya: Hi everyone. Welcome to Ask a Scientist, a Science Journal for Kids podcast where we explore what it’s like to be a scientific researcher. I am Tanya Dimitrova and I am here with my co-host – Dr. Miranda Willson.

Miranda: Hello.

T: Our guest today is Dr. Sarah Kienle. She is an Assistant Professor in Biology at Baylor University in Texas. Most broadly, she studies how animals function within their environment. This is an interdisciplinary field that combines ecology, animal behavior, morphology, physiology, and evolution. Much of her work has been with large marine animals like leopard seals, northern elephant seals, and grey whales. 

One of her latest research papers was about leopard seals and the variability in their traits and behaviors to assess how well they may adjust to climate change. This research was published in the journal Frontiers: Marine Science. And here at SJK we recently adapted it for school students. 

Today, we will talk with Sarah about her work but we will also get to know – at least a little bit – the person behind the professional scientist. Hello Sarah, welcome to the podcast!

Sarah: Hi, thank you so much for having me. 

M: Let’s start from when you were a youngling at school. Can you tell us a little bit about what kind of school you went to growing up and what kind of subjects you took?

S: Absolutely. So I am Texan, born and raised in Texas. I went to public school and had a pretty typical education. I believe it was in fifth grade where I learned the word “marine biologist”. I actually attribute it to a very young child actor Ben Affleck who at the time was in this program called “Voyage of the Mimi” that we watched in fifth grade. And it followed these scientists studying humpback whales. And there were lessons we did in class. And then we would watch the videos – it was this kind of educational series. And I think that must be where I learned the words “marine biology”. Because I also had a diary and my diary’s name changed to “Marine Biologist” at that point.

I thought a marine biologist was somebody who got to pick up seashells and play with dolphins. And that is not… I don’t do either of those things for my job. Although both still sound awesome. And I do really love picking up seashells! But throughout the rest of my schooling I just had this idea that I wanted to be “a marine biologist and an astronaut”, or “a marine biologist and a paleontologist”, “a marine biologist and a teacher”. So marine biology was always there and there usually was maybe one other career choice. 

I also took aquatic sciences as an elective in seventh grade and that just locked me in. It was like, ‘this is what I want to do!’ We went to the beach, we collected – got to see sand dollars, we looked at the intertidal zone, we saw sea turtles swimming, and my best friend and I had a dolphin come up near to us on a jetty after we sang a song. And I was convinced that our song had brought the dolphin over! Then it swam off and never came back. But it was just this kind of combination of magical moments in science where I was like: this is what I want to do with my life.

M: But you didn’t want to become a singer?

S: Yeah, right! I can hear myself singing and I know that is not a viable career path for myself!

T: Let’s talk about your time studying at university. You did your bachelor’s in biology and history from Trinity University in San Antonio, Texas. What’s up with the “history” part?

S: So history just came really naturally to me. I also had done a lot of AP classes when I was in high school and so I was able to transfer a lot of credits for history to my bachelor’s degree as an undergraduate. And so I already came in with a lot of units and it ended up being really easy to major in history. And I found that – I love reading. That’s something I do for fun as well. Reading long books is not daunting to me and I’m quite good at that. And so in history, I was able to make A’s very very easily. 

That was not the case with biology. Biology, I was passionate about – and I also loved – but, you know, I would hit some courses that were hard. And I was not easily making A’s in those classes. So I think it helped balance out my sanity being like, you know, there are these things I’m good at and there are these things I’m passionate about. They may not be exactly the same all the time but I was really willing to work at it. 

M: For you graduate degrees you moved to California. You did your masters in Biology at San Diego State University, and a PhD in Biology at University of California Santa Cruz. Will you admit it, you really just wanted to be at the beach?

S: I mean, I work with marine mammals! Being by the beach is a huge perk of the job.

M: So in those graduate programs did you study marine mammals the whole time?

S: I did study marine mammals the whole time. So I started off working on bones – doing a lot of skulls, working in museums. I did a lot of dissections – in the animal world we would say “necropsies” instead of “autopsies”. I did a lot of necropsies and dissections. I was working with a lot of dead things for my masters. Marine-mammal-focused. It was mostly seals, sea lions, I also did some grey whale work. 

And then my PhD work I was also still primarily – only working with marine mammals. I have a couple of side projects where I was doing some work with mountain lion hair samples but the vast majority of my work has been in the marine world.

M: I know you said you were studying some bones. Did you get a chance to go out in the field a lot while you were in graduate school and if you did where did you get to go?

S: Yeah, great question. So after I had completed my Master’s degree working in the museum collections and working with dead animals and looking at how their bodies are put together, and their form and their function, I became extremely fascinated by feeding.

So feeding is instrumental to survival. If you like living, you’re going to be eating – if you’re an animal. And I realized that I really wanted to see feeding happening in real life. If I’m studying feeding in these marine mammals, I would like to see the opportunity to observe them actually feeding. 

We conducted some feeding experiments to learn more about how wild animals are foraging and feeding in the real world. And so that really narrowed down where I applied for PhD programs, focusing on what I was looking for. I was looking for programs where I would be able to work with wild animals and do a feeding-based project. And so for my PhD I absolutely was working with live animals. 

I got to partner with a lot of zoos and aquaria and do these feeding studies to look at how seals and sea lions actually get food into their mouths. It’s way more complicated than you might imagine. They actually have different strategies depending on where in the water the animal is, where the prey is, what type of prey it is, how big the prey is. All of this influences how they actually eat it, how much energy they’re taking to feed, and how much energy they’re taking to catch the prey. 

I also did a lot of work with wild animals. I did a lot of work to put instruments on animals – seals in particular – that would track where they went at sea. You can look at all sorts of really cool data on their movement patterns, their diet, behavior, their foraging success, how much mass they’re putting on during a foraging trip – all sorts of really cool variables. That work took place in California, in Mexico and then, toward the end of my PhD, that rolled over into what I’m doing today: I started working very closely with an Antarctic-based species. So I went to Antarctica a couple of times. Now I’m working with this Antarctic species that’s found in other locations too.  Now I’m traveling to South America. I have a trip next week where I’m going to New Zealand to continue working with this cool species leopard seals. 

T: That’s so cool. We know you grew up in Austin, Texas. Now you are back in Texas as a professor. So how do you square that with studying marine animals (so working at sea) and not just anywhere but in the polar regions? Was Texas just too hot and dry for you and you wanted to get away?  

S: Actually it’s because I’m working with a species that is so remote. A lot of their population lives where humans do not live year-round. So it doesn’t matter where I’m based because I work with leopard cells that you can’t find in the United States or the majority of the world. The largest population is in Antarctica. So I can work from anywhere. And so I just travel. When I’m doing work that involves working with the animals directly and animal handling, then I’m traveling to where they are. It doesn’t matter if I am in California, in Waco, Texas, in Russia – it doesn’t matter. It’s just how long the flight is, depending on your location.

T: Right. So let’s talk about sex. 

S: Great. 

T: Throughout your career, you’ve consistently studied the differences between males and females – in different marine animals. In biology, the difference between sexes is called “sexual dimorphism” (from Ancient Greek meaning “2-forms”). What made you so interested in this difference between the sexes? Did you, like, read “Men are from Mars, women are from Venus” and thought: Oh, I wonder if that’s true for seals too?…

S: I have never read “Men are from Mars, women are from Venus” although I have referenced that book several times in jokes. I am a comparative biologist at heart. This means that I just am really interested in how representative is this of the whole species, how representative is this thing I’m finding in an animal – compared to these different groups. I’m always just asking a comparison question.

M: Can you describe for us a day in the life of a marine biologist? Before you answer, you might have two very different versions of this: one when you’re out in the field and one when you’re back in your university office.

S: I’ll start with what I do the majority of the time which is actually in my office at my university doing research that is not directly hands-on with animals. A day in my life would look like this: I’m waking up – if it’s during the school year – I have two young kids – I’m waking up, I’m getting them ready for school. I’m dropping them off. I have my breakfast taco and my chai tea drink. I get my computer going. I check emails. There are endless, endless, endless emails. A lot of my day is: I’m on my computer and I’m reading, I’m writing, and I’m thinking. That is the vast majority of what I do. 

There’s some computer programming thrown in, there’s some statistics thrown in. There’s a lot of talking and networking and collaborating with other people. That would be kind of my general day. That would end usually around 5 pm when my partner or I pick up our kids. Then we go home and, you know, have our home life.

Then I have the research portion of my job and that’s when I am traveling for research. I’m leaving on Monday for New Zealand, for example, and that’s going to be a research trip. When I’m gone basically my whole job is to be a researcher. So there’s no kind of normal working hours. It’s depending on the project and depending on the species and what our goals are. It’s sun–up to sundown. We’re just eating, breathing, living fieldwork. 

I just went to Chile in December to work with leopard seals. A day in that life was: we’d wake up on a boat, we would get up, have breakfast, put on all of our layers (because even though it was summer in Chile, we were by icebergs and a glacier so it was very cold). We would then go out and climb onto a small boat with all of our gear for the morning. We would go on a boat looking for leopard seals. Sometimes we were successful at finding ones. Usually in the morning we weren’t. So we’d come back for a delicious lunch. Then we would do the exact same thing in the afternoon: get back on the boat, we would do this whole procedure to get samples and photographs and data from the seal. That would take a couple of hours. We’d would continue looking for others and then by the time it was starting to get dark, we would go back to the boat, have dinner, do data collection, process our samples, go to bed, wake up, do it again. 

T: To be honest, the field adventures sound amazing to me but what you described about your university-based work, makes me wonder if you actually find time to sleep! How do you manage everything? You said you have your personal life and your work life but how do you prioritize or how do you find balance?

S: Yeah that’s an ongoing skill I’m still learning. I have two young sons – I have a seven-and-a-half-year-old named Kevin and I have a three-year-old named Oliver and my husband Sean. I will say that they’re actually really great for work-life balance! Because I cannot open my laptop at home when my boys are awake because it is a toy! They want to play with it. And that is really good for not being able to work! Because they want to open and close the lid, they want to push all the buttons, they want to type, they want to play on it. And so it’s just like: Okay, I guess I’m not getting any work done right now! 

But that actually is really great, right? I love my job, and I love my family, and I love having hobbies and interests outside of work. So for me, having that inability to open my laptop at home actually makes it really nice. I can turn off that portion of my brain while I’m at home and be really present there. And then I’m very productive when I’m in the office because I know that’s my only window. Unless I work when they’re asleep and usually I’m so exhausted I’m going to bed as well. It means that I’m not really distracted when I’m at work. I’m not goofing off on the internet, I’m not on social media when I’m at work. Because I know that this is my dedicated work time. So I found my productivity has actually increased since becoming a parent and having this separate home life because I have to. 

As I’m moving up and managing the lab, I cannot possibly respond to every email that comes to my inbox. There are things I have to say “no” to and that’s a word that’s very hard for me to do. I think that’s true for a lot of people, and women in particular, to say no to things. I’ve had to get better at it because I just am continually learning I cannot do all of it all at the same time.

T: Do you use ChatGPT or any other type of AI in your work?

S: Oh, that’s a good question. Yes and no. I have used it to just try and figure out if what I think is unknown, ChatGPT also thinks it is unknown. For example, I could potentially ask ChatGPT: Tell me about the leopard seal mating systems. I’ve done things like that before. Usually, what will happen is it would say we don’t really know much, it’s only been documented in one captive study. But here’s what closely related species do. For me, that’s useful. 

But the other day, I asked it to give me examples of species in which females were larger than males – in mammals – because I have a list I’ve compiled and I was curious if ChatGPT could give me other species. I was specific about mammals. It was so blatantly wrong! It talked about northern elephant seals – which are the classic example of male-biased sexual dimorphism! It talked about females being larger, females having large noses. It talked about spiders! It talked about birds! And I was like: Okay, that’s a good reminder to all of us that it is a work in progress.

I have used it more anecdotally in situations where I need help writing a nice rejection email. I’m going to say “no” to this thing, can you help me write a nice “no”-email? It does a really good job at that. ChatGPT is very polite and very kind. 

M: It sounds like you really love being a marine biologist – all aspects of it. But if you weren’t a marine biologist, do you see yourself in another profession? What other profession might you be in?

S: Before I went back to grad school, I was a high school biology teacher for two years and I actually loved it! I missed doing science and that’s what brought me back to graduate school – I missed contributing to the scientific community. But I loved the teaching aspect. So if I was not a marine biologist, I think it would be very natural for me to go be a science teacher. 

If that was off the table too because it’s too closely related to what I’m doing then I’ve jokingly said I would either be a guide on a marine mammal boat and go out on the boat and interpret the different animals we saw.

If that’s too closely related then I would want to work at a bookstore.

T: Let’s talk a bit more about leopard seals now. We’ll start with the very basic question from a listener.

Aili: Hi, I’m Aili and I am 6 years old. I have a question for you: Why are those seals called leopard seals?

S: Oh, that’s such a great question. The reason leopard seals are called leopard seals is that they have these black spots. And one of the cool things about leopard seals is it turns out that those spots are unique – like fingerprints almost – so you can use the unique spots of a leopard seal to identify particular individuals

M: That sounds really cool! In the research that we adapted of yours you studied sexual dimorphism in leopard seals (again, this is the difference between the two different sexes). It’s unusual for mammals but in these seals, females are larger than males. I’m sure you already knew that before you even started your research! But then you looked at the variability in those traits and the behaviors also of these animals to assess how well they may adjust to climate change. Is that a good summation of your research? Is there anything you want to add to the basic story?

S: That’s a great summary. I should say that even though they are these top predators in the Southern ocean around Antarctica (and actually across more of the Southern Hemisphere than we originally thought), you may have seen them actually in movies like “Happy Feet”, “Eight Below”, “Penguins of Madagascar”… Basically, if there’s a really scary seal in a movie, it is almost always a leopard seal. And I think this gives us a false impression that we know a lot about the species when it turns out we do not. 

We know very very little about this really important predator! There’s some really basic questions about their biology we’re still trying to figure out the answer to: like where do they have pups?

T: We don’t know that?

S: We don’t know that. Do they need ice for mating? How do they mate? One of the findings of the paper, as you mentioned, is that females are larger and that’s been noted a few times before, especially in the early 1900s. I’ve been reading a couple papers and they have some documentation too that they are noticing that females are larger than males. But there’s also this big question of why. We have no idea why females are larger than males. That’s now what I’m really fascinated by – trying to get a handle. 

Then the other big piece of it is they are living in a rapidly changing environment. Leopard seals as a whole – males and females – are living in an area that’s undergoing more rapid change than anywhere else on the planet because of climate change. And because we don’t know a lot of these really basic questions about their biology, it’s really hard to predict how they’re going to be affected by melting sea ice, by increasing ocean temperatures, by all of these changes that are already happening in their Antarctic homes. We don’t know how they’re going to respond without baseline data. So part of my job now is to try and collect some of this baseline data to start being able to make real hopefully meaningful projections about are they going to be okay or are they going to be in trouble and what might we do to help with that.

T: Does your research give you hope for the future of these animals?

S: My research does give me hope for leopard seals. What preliminary data from leopard seals are showing is that even with very small numbers, they’re really variable. They are showing a lot of variation in traits: males and females are showing variation, animals from different locations are showing variation, animals of the same sex in the same location are showing variation – in their movement patterns, their behavior, their diet. That’s all really good because the more variable you are, the more you can adapt to things that are changing in your environment. If you eat a lot of different prey types and one of them disappears, then that’s going to mean you’re going to be able to switch to something new or to switch to the other nine prey types you eat. 

Species that tend to be in more trouble or that we might be more concerned about are ones that are very rigid and strict and stereotyped in what they do – species that are only eating one prey type, for example, are going to be more at risk if that prey type goes away. They’re going to be much more affected by that. I am currently optimistic that leopard seals are going to be one of those species that potentially does just fine in a changing environment. 

But what I should also mention is that they’re top predators. Which means if they’re doing just fine or even doing well and moving to different areas, this is also going to have a huge effect on other species. Because they’re at the top, they are having a huge effect on other animals. 

One of the things my friends are finding in Antarctica is that they are wiping out populations of Antarctic fur seals! Because that’s one of their favorite prey sources. And so, in some areas they are eating up to 80% of pups that are born each year! So leopard seals, in this case, are doing very well. The Antarctic fur seals, in this case, are not doing very well. And so, you know, it’s like in “Finding Nemo” – “Birds gotta eat”… There’s always trade-offs. I find all this complexity really fascinating. 

T: We received some questions from a student reader. 

S: Oh, wonderful!

Adyant: Hi, I’m Adyant Bhavsar, an 8th grader from San Jose, California. Can you explain the specific methods you used to capture, immobilize, and release the leopard seals during the study? How did you ensure humaneness and ethics?

S:  That is a really great question. It’s something that any researcher that’s working with wild animals is thinking about quite a bit. The first thing I should say is that to work with wild animals and do the work I do, requires extensive permits. So many permits that take months and months and months of work to get. And that work is you reading all of the literature, that you are familiar with all of the processes, that you have talked to all the right people, that you know the best practices for working with those animals humanely, and that you are justifying every single thing you’re proposing to do with an animal based on the best practices. You’re justifying the sample sizes you want, you are doing all of the background work required before you would ever be able to even get close to an animal. So once all that’s in place, you have a well-trained team, you have the permits in place because you’ve justified the work you need to do and the science that you’re going to get out of it.

The actual sedation process of the animal really depends on the species. We were working with solitary animals – animals that were not hauled out in large troops. They were hauled out on beaches. Usually, what they’ve done is… they were at sea feeding; they’d had a giant meal of probably penguins or krill or Antarctic fur seals, as I’ve mentioned before; and they’d come back on the beach in a food coma, basically. They were snoring. 

Because they were by themselves, we would usually approach from downwind so that they wouldn’t be able to smell us. Then we have a long pole that has a syringe with the right drug combination in it. It’s got that spring-loaded, you just jab it in. It feels very much like a bee sting. These are needles that we use with humans (that people use with humans as well, not me in particular). Then you back off really quickly. Usually what happens is that the seal looks up, maybe looks around. Then if they don’t feel disturbed (usually we’ve backed off and we’re kind of crouching out of sight), they’ll go back to sleep. And they’ll start snoring again. It takes about 10 to 20 minutes before the animal basically is asleep, with the drugs we’re using. They were still snoring while on the drugs. It was pretty funny to hear seals snoring when you were up close working with them. 

We will take our samples and measurements as quickly as possible and back off. Some drugs have reversals, which means you can administer the reversal in the same way. And in about five minutes, it’s like the drugging never happened. So we’re usually out of sight because we don’t want them seeing us. We’re outside monitoring them until they are back to normal, until they’re moving normally, until they’re doing everything they were doing before. Usually, that means they move around a little bit and then go back to sleep. 

T: You should also make sure that you, the humans, are safe because these animals could be dangerous to you.

S: It would not be safe to get these samples from live, angry, moving individuals. In fact, that’s actually way more stressful for the animals – to be awake during procedures. Even for doing things like putting in a flipper tag that would let us keep track of individuals throughout their lifetime. Some of these things can be really stressful. If they see you doing that it can actually raise their stress response. Whereas research has shown that sedating them doesn’t mount a stress response. So it’s actually less stressful for them (depending on the species) to have sedation and then back off and stay out of their space. 

M: We understand that your research is probably pretty expensive – all those field trips and being out on the boat so much. So to end our interview today, we’d like to ask you: if you had an endless supply of money, what is that burning research question that you would want to answer?

S: Oh, I love that! Okay, if I had an endless supply of money what I would want to do is a comparative study across all Antarctic seals. There are four really closely related species that have all evolved to live there, they’re all each other’s most closely related relatives. 

There’s the leopard seal, the Weddell seal, the crab eater seal, and the Ross seal. I would love to do this large-scale comparative study of all four species at the same time: putting out tracking instruments, putting out video cameras, taking samples across their entire range (which would be the whole of Antarctica and potentially, more broadly in the Southern Ocean) to really understand these different trade-offs in their life history and foraging patterns. And how this relates to sexual dimorphism and not sexual dimorphism and how all this evolved. 

That would be an unbelievably expensive study that would involve many many different teams of researchers all working at the same time. But that’s my like pie-in-the-sky, the dream I have. I just think that would be such an amazing project. 

So many species we know a lot about (like Weddell seals) and other species, we know almost nothing – like leopard seals. But actually, there’s a species below that – Ross seals – where we know even less. And so it would just be phenomenal to see these animals operating in this environment in such different ways.

M: We’ll make you a deal: if we find that money for you, can we come as research assistants?

S: I will make that deal for you. You may be just taking data and photographs but that would still count. You’d still be there.

T: Thank you so much for your time today! We learned a lot about leopard seals, about your life as a professional researcher, and your path and how you got to wherever you are at the moment. So we really appreciate you spending the time with us. 

S: Absolutely! This was lovely. Thank you so much.

M: Did you know that you can directly read one of Sarah’s scientific papers stripped from its complex scientific jargon and made understandable to readers as young as 5th grade in school? The link is in the show notes. You can also just Google its title How can leopard seals survive climate change? Or directly go to and search for “seal”. 

T: That’s all for today. This podcast was produced with help from our student research assistant Adyant Bhavsar. Sound engineer Maria Mihailova and hosts Miranda Willson and me, Tanya Dimitrova. Thank you for listening. Subscribe to this podcast to receive notifications about the next episode of Science Journal for Kids’ Ask-a-Scientist. Till then.

That’s Not All!

You can read the student-friendly article by Sarah “How can leopard seals survive climate change?” here as well as watch a video of leopard seals. This article is available in Spanish (PDF) and in an English text-to-speech audio version.

Their original paper was published in the journal Frontiers Marine Science (link).

Get the latest updates on Sarah’s research at her website.

Finally, check out our podcast home page for the latest episodes of Science Journal for Kids’ Ask-a-Scientist podcast. You can subscribe to and listen to this podcast on any podcast platform or app.

All photographic images credit: Sarah Kienle. 

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