Bawan Amin: individual personality is evident from just a few weeks old

Bawan Amin, son of Kurdish freedom fighters talks about his latest publication in Functional Ecology “In utero accumulated steroids predict neonate anti-predator response in a wild mammal” as well the importance of asylum, family, and being able to pursue your passions.

At the time of writing, I am about to start the final year of his PhD-research at University College Dublin, Ireland. Supervised by Dr. Simone Ciuti, my research focusses on individual differences and life-history of fallow deer (Dama dama) in the free-living population of Phoenix Park, Dublin.

Bawan Amin in the field with a telescope tracked on fallow deer
Bawan Amin in the field with a telescope tracked on fallow deer

Why do animals do what they do? Understanding animal behaviour is becoming more important than ever, especially as we are faced with challenges, such as biodiversity loss and climate change. We need to understand the fundamentals of how animals behave, in order to understand if and how they can cope with a changing environment. If you follow that line of thought, you will find yourself at the topic of our recent article: what shapes an individuals’ behaviour?


What better place to start, then to study newborn animals, who lack experience and are therefore likely to show innate behaviour? Do newborns immediately show individual differences in their behaviour? And if they do, what are the mechanisms driving these individual differences? We provide a piece of the puzzle with our study, by studying individual differences in newborn fawns.


We caught 185 individual fallow deer fawns, in a free-living population, and looked at how they coped with being captured and handled. We found striking differences between individuals: where some individuals reacted proactively (heart rates of >150 bpm and are quick to run away), others reacted calmly (heart rates of ~60 bpm and stay put when released). These differences really seem to have an individual component, that is already clearly present within the first two weeks of life.

The release of a fawn at the end of the capture (photo by Crispin Rodwell)
The release of a fawn at the end of the capture (photo by Crispin Rodwell)

Not only is this finding in itself relatively novel, especially when studying large mammals in wild populations, but we also attempted to uncover what mechanisms shape these behaviours. We took a bit of hair from the fawns during capture, from which we measured chronic levels of cortisol and testosterone – both of which are important steroid hormones. Since these animals are newly born, chronic hormone levels are accumulated in the womb of the mother, and therefore, these samples gave us a unique picture of the environment in which the fawn was developing.

UCD students release a newborn fawn after tagging, weighing and measuring it as part of the annual tagging programme of Phoenix Park’s newborn fallow deer fawns. Photograph by Crispin Rodwell for the Irish Times


We found both hormones were associated with the fawns’ responses, although in opposite directions. More cortisol was linked to a more active response, whereas more testosterone was linked to a calmer response. In other words, these hormones in utero may have a crucial role in shaping individual behaviour.

Fawning season in Phoenix Park, Dublin, Ireland (photo by Crispin Rodwell)
Fawning season in Phoenix Park, Dublin, Ireland (photo by Crispin Rodwell)


This research is unique, because it uses a relatively novel method (hair steroid quantification) and it is the first to report these findings in newborns of a wild large mammal. As a result, it provides new insights into how individual behaviour is shaped in an ecological setting. Of course, this is only a starting point, and it raises many new and interesting questions. For example, what is the source of the hormones (maternal or foetal)? Are these effects long lasting? Do they impact survival? All of these are pieces of the puzzle that we hope to slowly solve as scientists, and I am confident that we will gain many more answers in the coming decade.

The importance of a great study population
We are lucky enough to be studying a population of fallow deer in the largest urban park in Europe, namely Phoenix Park, Dublin, Ireland. This population has been monitored for decades now, and a crucial part of their management is the ear-tagging of newborn fawns. All the data used for this study was collected by our team during the fawning season when tagging takes place. Since the tagging programme has been ongoing for many years now, we have a pretty good idea of where the fawns are. This creates the unique opportunity to sample the majority (~80-85%) of all the newborn deer in the population – something that is extremely rare when it comes to larger free-living mammals. This also allows us to do exciting research, as we can follow these tagged newborns longitudinally throughout the different stages of their lives.

A newborn fawn lies in long grass in Phoenix Park, prior to being tagged as part of the annual tagging programme of the Park’s newborn fallow deer fawns. Photograph by Crispin Rodwell for the Irish Times
A group of hinds watch from nearby as their fawns are caught and tagged as part of the annual tagging programme of Phoenix Park’s newborn fallow deer fawns. Photograph by Crispin Rodwell for the Irish Times

About the author
I could start off here by saying how interested I have been in animals since I was a kid. And of course, that is true (weren’t we all like that?), but I would rather use this space to show how incredibly lucky I have been, and how little of it has been in my own hands. At every single step of the way, I have been lucky enough to have someone to support me or make choices that have significantly increased my chances.


I was born in 1992 (one year after the Kurdish uprising), in the city of Slemani, part of the Kurdistan region in a war-torn Iraq. Born as the only child of a freedom fighter and a biology teacher in Iraq, no one would have guessed I would end up doing science in the Western world. We had to flee as political refugees and were able to seek asylum in the Netherlands in 1997. My parents worked tirelessly to build a new life in the Netherlands, which was not easy for two adults in their early 40s. Every night they worked until 2 AM, learning the language and trying to find a job, all so I would be able to grow up in a safe environment, which was something they did not have. They (and the Netherlands as a country) provided me with an environment where I had the luxury of being able to focus on life sciences.


After secondary school I was able to go to university to do my BSc in Biology, although I never had good grades prior to that. I saw studying biology as a new chance and wanted to give it my best. Question-driven, I was always fascinated by that same question: “why do animals do what they do?”. Again, at every step of the way, I was lucky enough to have the right supervisor who supported me. People that looked past the grades. It is thanks to all these people, who saw past the superficial and past ethnicity, that I was able to continue. Now I am doing my PhD in Dublin, at UCD… Can you believe it?! Of course, working hard is also part of success, but something we do not always acknowledge is that hard work is not enough. You need to be at the right place, at the right time, to really push through. So far, I have been lucky enough to have that and I am beyond joyful to be able to do what I love: solving puzzles about life.


Recently I finished my fieldwork and took a photo to celebrate it. My dad had a similar portrait, from when he was about the same age as I am now. He described it much better than I could: he was carrying an actual weapon, fighting for freedom. I am lucky enough to be carrying a weapon of science, fighting for knowledge.

Read the paper in full here.

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