One Long Line: Marching Caterpillars and the Scientists Who Followed Them

Discovery Chronicles

by Loree Griffin Burns, Jamie Green (illustrator)

A fresh and fascinating look at caterpillars gives new meaning to the words “line leader”—and ushers kids into the process of scientific discovery—in this first book in the Discovery Chronicles by a biologist and award-winning children’s author.

This is a story about remarkable creatures, inquisitive people, and fascinating conversations. The creatures? Pine processionary caterpillars with mysterious group habits. The people? Jean Henri Fabre and, many years later, Terrence Fitzgerald—scientists with big questions about the behavior of these caterpillars. And the conversations? The conversations span lifetimes, as one researcher continues a dialogue started by the other. In this playful, candid, and accessible book for young readers, biologist Loree Griffin Burns captures the unique leader-follower behavior of pine processionary caterpillars through a glimpse into the “ask, test, repeat” nature of the scientific process—and shows how that process creates one long line of questioning and learning. Back matter includes more details about the two scientists as well as a glossary, bibliography, source notes, and suggestions for further reading.

Genres: Nonfiction, Science, Childrens, Juvenile, Nature, Middle Grade, Chapter Books

64 pages, Paperback

Published August 26, 2025

About the author

Loree is a scientist-turned-writer specializing in books about science and nature for young readers. You can learn more about her adventures and her books by visiting her website (www.loreeburns.com) or by following her blog (http://loreeburns.com/category/blog/).

Reviews

[Brittany Hilgemeier · Rating 4 out of 5]

This is a great read if you have observers like my boys. We also read a good deal of non-fiction, especially animal and insect facts, so this was already up our alley.

What was fun about this story in particular was the way that it broke down the scientific method so that it was approachable to young kids. We get to see each scientist observe the pine processionary caterpillar and pose questions. Then the narrative encourages the reader to consider how you might conduct an experiment to answer the question. It also thoughtfully explored the way that science builds on other people‘s previous research.

We checked this one out from the library, but it feels like one I’d like to get my own copy of.

[Kimberly Eshleman · Rating 5 out of 5]

I loved this book so much! I read it aloud to my 3 boys and we all kept wanting to read just one more chapter to find the answers to all the science questions that were posed. I learned just s much as a 40 year old, college educated mom, as my 3 young boys (ages 5, 8, and 10) did. One of the best children's books we have read in quite some time!

[Kaitlin Ross · Rating 5 out of 5]

A fantastic read for any curious or science-minded kids! Good explanations through story of the scientific method.

[Jessica · Rating 4 out of 5]

A clear, readable, interesting look at the nature of science. I’m planning to use this as a read aloud for my third graders when we study insect life cycles.

[Jan · Rating 5 out of 5]

Although born more than a century apart on different continents, the work of Jean-Henri Fabre and Terrance Fitzgerald shared a passion for the humble pine processionary caterpillar. Working in France, the late 19th and early 20th century, Fabre was a talented teacher who published popular narratives of his observations of insect behavior. He was fascinated by pine processionaries, social insects who, in their larval stage, live communally. When leaving their nest to forage for food, the caterpillars travel in a long continuous line, with the head of each caterpillar touching the tail of the one in front of it. Working decades after Fabre’s death, Fitzgerald, an American entomologist, built his research on Fabre”s observations. Their work demonstrates the crucial role of curiosity in the scientific process. Scientific inquiry calls for careful observations which often can be done without fancy laboratories or elaborate proctocols. Anyone can be a citizen scientist! This slender volume of engaging narrative is enhanced by digitally rendered black and white illustrations that succeed in being both detailed and expressive. From the Discovery Chronicles series by MIT Kids Press, One Long Line includes a Glossary, References for Further Study, Source Notes, and Bibliography. Recommended for ages 7 to 10 by the SEPA Book Reviewers.

[Barbara · Rating 3 out of 5]

Although the text is engaging, threading in questions about caterpillars that scientists were trying to answer with one resolved question leading to another query and another, with mistakes made along the way, I wish the book [3.5 for me!] had been published in a larger format. While quite serviceable, the digital illustrations made me curious about how the caterpillars and those scientists might have appeared if rendered in the traditional full-color images and size typically found in picture books. Still, the way the entire production hangs together, honoring the process and nature of scientific inquiry, makes the book accessible, engaging, and informative. As with all her books, this author clearly loves exploring the natural world, especially those aspects of it those most readers tend to overlook or take for granted. Overall, this is a solid start to what promises to be a fascinating series sure to inspire some youngsters to seek out a career in one of the sciences.

[Lynn · Rating 5 out of 5]

You don't have to be an entomophile to appreciate this book on caterpillars and the scientific process utilized by two scientists who spent much of their lives studying them.

Jean-Henri Fabre and Terrence Fitzgerald lived in different centuries and in different continents but the desire to answer questions and to ask more questions led to the unveiling of answers on how pine processionary caterpillers and tent caterpillars move and communicate.

It is a refreshing book which primarily deals with the process of asking questions, formulating a hypothesis, devising experiments to test that hypothesis, and ultimately coming up with a conclusion.

The book also shows us that contrary to popular propaganda, the science is not always settled, as Fitzgerald takes on the work of Fabre to test and challenge a conclusion the latter had derived earlier.

Great information all around and a reminder what science is really all about.

[I Trump · Rating 5 out of 5]

This is an excellent example of narrative nonfiction for children. It is written in such an accessible style that it was engaging the whole time. It's important to read how one scientist builds on another, adding to, and sometimes disputing, another scientist's conclusions. So many adults don't understand about how this works. They should read this book! Not only will children learn about caterpillars and experiments, but this book sets them up to ask their own questions and spark their own curiosity. I also appreciated that care was taken when a few caterpillars were harmed. Highly recommended!

[Theo Scully · Rating 4 out of 5]

~ read for Capitol Choices ~

This is a fun and accessible title about caterpillars and their marching patterns. While I am not going to start researching caterpillars, I enjoyed reading it. The illustrations and writing style are geared towards 6-9 and allow for a familiarity. I especially liked the trigger warning on page 44 before discussing an experiment where a caterpillar was killed. The glossary, bibliography, and further reading sections are up to date and concise. A great resource for budding scientists that focuses on the research and experimental
processes rather than a specific topic.

[Cosette · Rating 5 out of 5]

Sometimes parents ask me what their children should read. I’m not sure why parents do this when my favorite authors for children are Denys Cazet and Gordon Korman. But, putting this aside, this is the book I will recommend kids read over the summer. This and Weslandia. You know what’s helpful? This hook has a glossary that explains why the word instar is used when discerning the life cycle of a bug, something I didn’t know previously. And there is a list or recommended readings inside! You know I like recommendations, even if I can’t believe people still read the same author that disappointed them last month

[Martha Meyer · Rating 5 out of 5]

A fascinating story of two scientists, separated in time and place, who studied pine processionary caterpillars. The book is also about the scientific method and how scientists ask questions of the caterpillars by constructing experiments and how the caterpillars responded in those experiments. Terrific! (This book is written by the author of Honeybee Rescue and also You’re Invited to a Moth Ball, both excellent. This book is for much older kids and is much longer.) Thrilling as you learn the results of each experiment!

[Sneed III · Rating 5 out of 5]

Like its caterpillar subjects, this book presents two connected stories of scientists who took an interest in the same topic, decades apart. It's a great example of how science arises simply from people being curious enough to ask questions—and to try to answer them. Besides inspiring the scientist in all young readers, it opens up the fascinating world of insect behavior, something too many of us take for granted. Parents and teachers alike will find a procession of topics to explore through this simple, well-told children's book.

[Lisa · Rating 4 out of 5]

I have seen firsthand the devastation of trees and anything green in Northern Minnesota when the “army worms” come through. Learning about the studies of Jean-Henri Fabre with the pine processionary caterpillars in France in 1896 was interesting. However, it was also cool to learn how Terrence Fitzgerald continued those studies with tent caterpillars in the United States. Terrence Fitzgerald even brought processionary caterpillars from Catalonia, Spain, to the United States so that he could further Fabre’s findings. Fitzgerald is still alive today.

[Lisa · Rating 4 out of 5]

I have seen firsthand the devastation of trees and anything green in Northern Minnesota when the “army worms“ come through. Learning about the studies of Jean-Henri Fabre with the pine procession caterpillars in France in 1896 was interesting. However, it was also cool to learn how Terrence Fitzgerald continued those studies with tent caterpillars in the United States. Terrence Fitzgerald even brought processionary caterpillars from Catalonia, Spain, to the United States, so that he could further FBre’s findings. Fitzgerald is still alive today.

[Lynn · Rating 5 out of 5]

This had excellent writing for younger readers: relatively simple sentence structure but fascinating and carefully accurate. The incorporation of inquiry and the scientific process was exceptionally well done.

I learned so much about these extraordinary caterpillars and nature-minded kids will be absorbed by the book. This is a perfect choice for STEM classrooms!

Attractive design and illustrations make this one very appealing as well.

[Hannah Schwager]

This is an official review from CLEAR, a group of librarians with SWON.

An adorable non-fiction for younger readers. The book explores how two scientists from different time periods studied marching caterpillars. The book poses questions to the readers, showing the process of how the question came to be and how it can be answered. I'd recommend this book to science lovers between the ages of 8 and 11.

[Sarah Albee · Rating 5 out of 5]

I had the chance to read an advanced copy of this book and have also just read the final, in-print version and I LOVE everything about it--the writing, the illustrations, the design, and the story. I also love the parallels between the line of caterpillars and the long line of scientific inquiry. Every school/library/educator/kid who loves science should own a copy.

[Isabel Scales · Rating 4 out of 5]

Nonfiction
3rd-6th grade
I liked this book because it was interesting and taught me real facts in a simple way. It explains how scientists study things step by step, and it makes learning science easy to understand. The pictures and examples help a lot too. Overall, it’s a good nonfiction book that teaches you something new without being boring.

[Sara Hudson · Rating 3 out of 5]

An engaging look at the scientific method in action that will appeal to young scientists. Would be a great read aloud in a classroom setting while studying the scientific method - the narrative format breathes life into a slice of nonfiction.

[Christine Crawford · Rating 4 out of 5]

This is an accessible and interesting little book for children about caterpillars and science. It won't be for every kid, but thoughtful, scientific-minded kids will enjoy the information and the nice, monochromatic illustrations.

[June · Rating 4 out of 5]

Interesting book about caterpillars (pine processionaries) and the scientists and their studies of them.

I was unfamiliar with both and was intrigued, though I did find the format a little unappealing.

[Margaret Boling · Rating 4 out of 5]

1/5/2025 ~ The first 3 pages of this book are a phenomenal example of a hook. I was intrigued right off the bat.

Sadly, I don't think this book is going to find many readers UNLESS it is hand-sold by librarians & teachers. Consider using it as a read aloud!

[Melinda Bender · Rating 4 out of 5]

Interesting look at caterpillars and their behaviors. Scientist Henri Fabre found how caterpillars follow each other’s pheromones and that’s why they appear to march in straight lines when traveling. Fascinating research.

[Rachel · Rating 3 out of 5]

Caterpillars and good science book that is almost an early chapter book. Good for teacher rec's

[Debbie]

What a sweet read about science and the study of caterpillars.

[Lindsey · Rating 5 out of 5]

Goodreads giveaway winner / free book review:

This is so cute and informative! Great book for kids and even adults. I loved it. I wish it had been around when I was a kid.

[Audrey Sauble · Rating 5 out of 5]

A really fascinating book about an unusual type of caterpillar and the two men who spent years studying them.

[Melody · Rating 5 out of 5]

Incredibly interesting story of two scientists who have studied marching caterpillars.

[Mary Lee · Rating 5 out of 5]

At around 50 pages of text, this is just the right length for young readers. The topic is fascinating, and the two scientists are inspiring. Highly reccomend.