‘In Ethiopia one night, a lion came near my tent’

HSE University Faculty of Mathematics graduate Sonya Pashchevskaya did not become a mathematician but went instead into the natural sciences. However, her university background comes in very handy when studying the bonobo great apes. In this interview with Age-mates, she talks about the advantages of tent life, the application of graph theory to primatology, and a female ape named Olga.

How did you wind up at HSE University?

I graduated from high school in Krasnodar, where I’m from, and entered the local math department at Kuban State University (KSU). I hadn’t originally planned to study math, but my father, who is a mathematician, talked me into it. And once I started at KSU, I got interested in math. I began studying a lot, but after two years, I felt I couldn’t stay. I attended a summer math school at Dubna and realised how much the mathematics community in Moscow differed from that in Krasnodar. So I decided to transfer to Moscow. At first, I planned to study at the Mechanics and Mathematics Department of Moscow State University, but after visiting it, I changed my mind. The FoM at HSE University had just opened at that time and I met a teacher from there who told me many good things about it.

It was the beginning of my third year, but I decided to transfer into the first year because the level of mathematics there was much higher. At the HSE FoM, the system is completely different from other faculties: they solve actual problems and don’t write theorem proofs on exams. I had to prepare for this format all through the fall in order to pass the exam in December. I stopped going to my math department at home and began frantically training to solve problems. It was quite nerve-racking, but I enjoy overcoming difficulties.

I first visited HSE University in November to get acquainted with the mathematics building on Vavilova. It turned out to be great there. The FoM is small and everyone knows each other. The typical hierarchy doesn’t exist: students and teachers chat with each other in the corridors. Everyone is passionate, and this was sorely lacking in my math courses at home. I met the teachers and felt that I would be welcomed there. I returned home, passed my exams in December, learned that I had been admitted, and moved to Moscow in January 2010.

Were the studies difficult?

There were very difficult, very intense. This is a very difficult faculty. And it differs from others in that a large percentage of FoM students remain in mathematics. This is the best place to be if you have such career plans. I didn’t intend to remain in mathematics, but my studies gave me a lot. The FoM taught me how to think abstractly, study well on my own, and extract information and process it. I began noticing that people have completely different powers of intuition in different areas. I have strong intuition in the natural sciences, which is what I do now.

How did this transition happen?

I graduated from the FoM in 2013 and began thinking about how to change fields. The task seemed impossible: I lived in Moscow at the time but I wanted to study bonobos in the African jungle. But my first husband—mathematician Daniil Rudenko, who earned his PhD in mathematics under Sergey Lando—was approaching the time to start his postdoc. The University of Chicago was the best match for his interests. My half-sister, who is 12 years older than I am, lives in Chicago. She is a neurobiologist at Northwestern University, but I became interested in biology long before I met her. Daniil and I decided to move to Chicago in one year. The plan was for me to learn the equivalent of a bachelor’s degree in biology in that time. I ordered American textbooks, watched MIT biology courses online and read scientific articles. I studied every day for eight months and passed the GRE test in biology.

We moved in November 2015. Daniil was accepted as a postdoc and I began working as a volunteer in two labs at the University of Chicago. They did not match my scientific interests: in one, they studied the morphology and the phylogenetics of fish, and in the other, the development of songbirds. I helped collect, categorise, and process data. Most importantly, I made connections. It was one more step towards the Congo.

What happened next?

My original goal was to get to the bonobos. Wild bonobos live only in the Democratic Republic of Congo and only south of the Congo River. A particular project studies them called LuiKotale. However, they don’t take people without field experience. Then I was accepted by a project in Ethiopia for observing hamadryas baboons. I spent 10 months living in a tent there. As I had expected, these conditions suited me perfectly.

Was it ever dangerous?

One night, a lion came near my tent and woke me up with a growl. Lions are territorial; their roar can be heard for several kilometers, which is made possible by the morphology of their pharynx. This one was about 13 meters away. The vibrations woke me up. It was a wild, bloodcurdling sound. I felt as though my body was suspended above the bed. I lay like that for several hours, wondering how I would go to work—and I couldn’t sleep because I could hear him perfectly. The lion lay down and his breathing made a terrible noise. It was a moonless night and completely dark. In the end, I managed to leave the tent, get ready for work, run to the car and drive away.

When did you arrive in the Congo?

When I returned, I finally applied to my dream project. And they accepted me. Four years after I had first wanted to go to the Congo, I went and spent a year in the jungle. The camp stands in the middle of the forest. It consists of tents inside huts with walls and roofs made of sticks. You fly on a small Cessna, taking off from Kinshasa, the capital of the Democratic Republic of Congo and landing on a makeshift airstrip in a village in the savannah. You then travel another 25 kilometers to the camp, crossing the river by boat along the way. There is almost no cell phone coverage there. All communication is through a very expensive satellite phone for emergency use only and an antenna that can send short emails with no attachments by shortwave several times a week. Water comes from the river: you use it for washing and for drinking. The project is led by a German couple, Barbara Fruth and Gottfried Hohmann. Barbara became my academic advisor. I assisted her on a PhD project so well that when I returned, I became a co-author of an article that was published in a scientific journal. Then they invited me to get a PhD under their supervision. For that, I first had to complete a master’s degree. Because of the pandemic, I had to do it online—at Liverpool John Moores University. During the courses at the beginning of the master’s programme, I chose a topic that hearkened back to the Faculty of Mathematics.

How so?

I have always been interested in complex social behaviour in interesting animals. In bonobos, it is rather unique for various reasons. I wanted to study it using my strong background in mathematics. At one class, I became interested in a methodology called social network analysis. This has been used in primatology a little more frequently in recent years. This is essentially graph theory, where your animals are the vertices and the relationships between them are the edges of the graphs. You can use different mathematical metrics that biologists can assign biological meaning to and look at what comes out.

I studied discrete mathematics under Sergei Lando. I am familiar with graph theory. Again, it turns out that, unlike many of my fellow primatologists, I take great pleasure in reading scientific articles from other fields that are referenced in the methodology of articles on primatology. I thought that I could introduce a very complex and powerful set of tools into what I wanted to study in a way that was natural for me. So I decided that this would be my main topic, and I did my master's work using this methodology. My PhD project, due to start next year, will take me even deeper into this. As part of the project, I will spend a third or half of the time at the LuiKotale camp collecting data. I'm also going there in March for a few months.

What is the theme of the PhD project?

‘Social networks in wild bonobos as a framework for studying fission-fusion dynamics and female migrants’ integration.’ During the day, bonobos break up into subgroups, and then merge again. This dynamic can be studied. And also the dynamics of integration of newly arriving females. Females migrate when they are close to puberty. They go to another community to avoid inbreeding. The way they integrate into the group is very interesting. Methodology can also help in studying this.

Do the bonobos know they are being observed?

Yes. To do research on wild animals, you first need to habituate the group to your presence. With bonobos, this takes about four years. They gradually cease to be afraid. We have two groups that have long been accustomed to us. We follow them all day long, observing them according to a certain protocol. We come no closer than five meters. The farther the better, but this is a dense rainforest and you can’t see further. Bonobos are okay with this. Our goal is to study behaviour in the wild while having minimal influence on them. Everything is non-invasive. We never touch them. It's like what Jane Goodall did with chimpanzees.

Were the bonobos everything you had hoped they would be?

Yes, they’re wonderful, unusual, interesting. I feel a great connection with them when I’m there. They know us field workers. You can see that they react differently to different people. They also single out new people in a rather obvious way. When I returned to the camp for the second time after earning my master's degree, they didn’t treat me as a new person. It seems like they recognized me.

Do you have a favorite bonobo?

There are a few. One female is called Olga, like my mother. She was the first bonobo I ever saw. She descended at dawn from a nest in a tree. It was a dream come true.

Do the living conditions in the camp bother you at all?

I like them. I breathe fresh air, fall asleep to the sounds of Africa, see a lot of greenery, and swim in the river. There are no noises, the food is simple and good, there few people and relationships for the most part are simple and satisfactory. There is no Internet or social networks with a billion messages—all the things that distract us. I have the most amazing dialogue with myself when I'm there.

Would you like to write a book about it?

This is one of my goals. I write a lot, both fiction and non-fiction. In the future, I want to write novels, non-fiction, and memoirs about my adventures. In Ethiopia, I wrote a blog called Sonya and the Hamadryas Baboons. It was very funny. Many of my friends as well as strangers read it. Now I'm writing another one (Sonya of the Jungle) because I lost access to that one after being offline in the Congo for a year. I have always thought of myself as a writer. I have been writing poetry for 20 years and I have nothing published in prose—but I’ve written a lot. When you do science, there’s little time for anything else.

What do you most want to learn through science?

Many primatologists are interested in learning how humanity has evolved. Studying our closest relatives in the wild is one of the best ways to do this. We separated about seven million years ago from bonobos and chimpanzees, from this branch that leads to the genus Pan that includes two species—Pan paniscus and Pan troglodytes. We know nothing about what our common ancestor looked like, what he did. But the more species we compare ourselves with, the better we can build a model of what our evolution could look like and correlate it with the findings of paleontologists. Some people believe that by the end of this century there will no longer be any great apes in the wild because of habitat destruction and hunting. As a scientific community, we have one last chance to learn something that we won’t be able to observe later.