Published: March 8, 2017

Women in Science: Lesley de Souza, Conservation Biologist

Lesley de Souza, Lead Conservation Ecologist, Keller Science Action Center


Lesley de Souza does fieldwork in the Amazon basin of South America, exploring waterways for fish species and working alongside indigenous communities.

A woman, standing waist deep in water, tags an arapaima, a large freshwater fish. A man helps to hold the fish while several people in the background watch.

We're highlighting women in science at The Field Museum and their diverse areas of research, paths to working in science, and their advice for future scientists. Hear from Lesley de Souza, conservation biologist in the Andes-Amazon Program:

How did you get to where you are?

Three people hold a large green net across a shallow part of a river

Ever since I was a kid, I would run around woods and creeks with my younger brother looking for critters. We were always curious about what we could find in hidden spaces. Our family spent many vacations camping or visiting our farm in Brazil, and this natural affinity for the outdoors led me to pursue a career in science. In college, I had an opportunity to be a field assistant on a project and found that the work I was doing was reminiscent of my childhood, traipsing in creeks and rivers looking for critters.

I continued to pursue fieldwork from Alabama to Alaska. These experiences inspired me to pursue my doctorate in Neotropical Ichthyology (the study of fishes), which led to the last 13 years of working in the Amazon basin of South America. Throughout my experiences in South America, I was most impacted by the indigenous communities I worked alongside. Because of the people I met, my interest shifted from researching the molecular ecology of neotropical fishes.

Now, my greatest passion is understanding how the science I am doing can be applied towards conservation efforts for wildlife, indigenous peoples, and the landscapes they share. Often the relationships between wildlife and indigenous communities are symbiotic, and these communities are passionate about conservation. I want to make sure those voices are heard and honored.

What does your job entail? What's the day-to-day like? 

Four rows of people, many of them children, posing for a photo in a forest surrounded by tall trees

I have a diverse suite of duties that fill my day as a conservation biologist. There is the South American fieldwork component and, the flip side of that coin, my office work at The Field Museum. When I am in the field, I spend my days sleeping in the jungle, trekking through the forests and exploring waterways for fish species. Most expeditions result in the discovery of new species. This work is accomplished with a lot of help from indigenous peoples of the region and enhances the knowledge we gain about the fish fauna of the region.

Upon return from fieldwork in the jungles of South America, fish collections have to be sorted and identified. This is no easy task! Therefore, collaboration with taxonomic experts from the various fish groups is crucial. It is important to document this work through scientific publications and share at international conferences via presentations. I also spend time keeping track of the work other scientists are doing in the region by reading scientific journals while in the office. 

What's your favorite part of the job, or a memorable moment?

It has been most rewarding to do science that can be applied to conservation efforts, while learning from indigenous peoples and scientific colleagues along the way. There are so many moments that are burned in the back of my mind, like seeing impressive jaguars roam the forests, swimming with arapaima (the largest freshwater-scaled fish—up to 10 feet long!), watching the magnificence of a harpy eagle in flight, and sleeping in my hammock in the jungle and seeing more stars than I thought existed—so many they light up the sky and are reflected by the river.

There are also many moments in the remote jungles where I am sitting among the indigenous people and they share stories of their beliefs, stories about the ways of ancient civilizations and tales of the animals and plants of the forests. Most memorable is a story of mermaids living in the river and how jaguars are really their ancestors who have passed away. My career as a conservation biologist keeps evolving, and at all of these turns, I find that working with others in the field or in the office has made me a better scientist. It has been a journey of ongoing explorations both professionally and personally; the exciting part is that there is more yet to come!

What advice do you have for future scientists?

Say yes and maintain a spirit that is inquisitive! Be open to various opportunities that allow you to explore the diverse disciplines in the sciences. This will help you fine tune your interests and skills while incorporating what you have learned from the different fields. And finally, work together! So much can be accomplished when you work together with scientists and community members, uniting your various talents and skills. 


Lesley de Souza
Lead Conservation Ecologist, Keller Science Action Center

Lesley is a conservationist with a special interest in Neotropical fishes. Her research focuses on understanding fish diversity in the Amazon basin and utilizing this scientific research for community-based conservation efforts.