Nothing Stays Put!

Teaching Children the Science (and Heartache) of Moving

Today, the first truly chilly day of a German October in the huge city of Berlin, and during a walk to the supermarket I was thinking about how I’m living in this apartment and this city, in the unconventional October weather, and on my way to this supermarket located behind a protected green area with pine trees and two squirrels I visit almost every day. Still, it’s almost certain that I will not live here forever… I may even move tomorrow… because who knows, right?

My thoughts got me to a time in the past when my parents had to move twice to a different country for a better chance of work, and of course they took my brother and me along; when my entire life changed, my view of my parents got distorted, and my relationship with life was disturbed. So my thoughts about the past led me to the question: how do you break this news and explain moving to children? The news that life is variable and was actually never meant to be stable—how do you train a tiny, fresh, clean brain to accept the disappointment or understand uncertainty? Something that we adults are struggling to accept and understand to this day?

How do you bring a kid into this world, give them a safe place to live, a healthy routine that gives them the freedom to grow and explore the world, friends and teachers at school they consider a second family, and two squirrels to follow every afternoon, and just in the blink of an eye extract them from this world they grew up in, from the world they built up, from the love they experienced and attachment to the place they call home? And worst yet: how to convince a child who is already born in a place in which you’re still struggling to call home and explain to them why they look different from other native kids at school or why they have to travel every summer to meet their relatives in a country they can never bring themselves to call home?

An emotional wave struck me with those thoughts, and then my brain got distracted by the squirrel when I spotted it on my walk back home from the supermarket. It was nice to see one of them again because I thought they would disappear in the cold months leading up to the brutal German winter. That snapped my brain back into focus: do squirrels migrate? Most animals migrate when the environmental conditions and food availability change, and this means even animals change their homes… could those two squirrels move to a different area in the big city of Berlin if it gets too hard to find food or shelter?… Wait! That would be a good way to introduce it to a child, and especially the 3-year-old child inside of me… animals are always the best characters in children's stories.

After some research, I discovered that squirrels—especially Eastern gray squirrels (Sciurus carolinensis), as reported by North Carolina State University ¹—sometimes travel in groups when food becomes scarce during the cold weather. Thankfully, my squirrels—reddish-brown Eurasian red squirrels (Sciurus vulgaris)—live in pairs, store their food, and build homes in tree cavities. In the cold weather, they rely on these nests for winter shelter rather than completely disappearing; in fact, research shows they tend to change nests rather than migrate or travel long distances when they stop feeling safe or when their homes are disturbed ². So I guess, until the freezing German November arrives, I have a few more weeks of following my squirrels on my trips to the supermarket.

Butterflies, whose life cycles are quite dynamic, offer another example: the beautiful Monarch butterfly (Danaus plexippus) migrates to overwintering areas where conditions are suitable for surviving the cold season ³. They return north as temperatures rise in spring, laying their eggs along the way. This means the trip home actually spans many successive generations; kind of like how families part ways, have kids, grandkids, and then a generation down the line finds the conditions suitable—or is forced by life’s hardships—to return home.

Having said that, for certain species of animals, migration is the only option for protecting their babies. Humpback whales—the most fascinating creatures on the planet, in my humble opinion—feed in cold, productive waters and travel thousands of miles to warmer breeding areas where their calves are born ⁴.

Salmon offer another remarkable example. Many begin life in freshwater rivers, migrate to the ocean to feed and mature, and eventually return to freshwater to reproduce. What makes their journey particularly fascinating is their ability to navigate back toward their natal rivers. Research suggests that salmon use Earth's magnetic field as a navigational map to approach their home region, then rely on their remarkable sense of smell to identify the exact river in which they were born ⁵.

But nature does not only show these stories of relocation on the grand scale of oceans and rivers; it scripts them deep within the microscopic architecture of life itself. It was recently suggested that pigeons have immune cells (macrophages) containing iron-rich particles with magnetic properties believed to help them track their way back home; the exact mechanism remains unexplained and heavily debated by physicists, proving that even science struggles to fully map out the mechanics of finding one's way home ⁶,⁷.

It is interesting how even immune cells in humans, the macrophages, move when they detect danger. They migrate to a safe space (secondary lymphoid organs) to start activating the rest of the immune system and launch a fight against an invader. In fact, most immune cells constantly move and change location based on external signals, a lack of safety, or even a scarcity of food. Neutrophils squeeze out of blood vessels to reach the site of injury or infection, and even the highly intelligent T-cells move across a gradient of protein signals sent by other immune cells or infected tissue ⁸,⁹.

Taking this thought a step further, we can reflect on how atoms are in constant motion, encountering and bonding with one another to form molecules—the building blocks from which living organisms emerge. Within cells, glucose molecules are transported across membranes and processed through intricate metabolic pathways, helping cells obtain the energy they need to function. During human reproduction, millions of sperm begin the journey toward a single ovum, though normally only one fuses with it. From this union emerges an embryo with a distinctive combination of genetic information, a new arrangement of chromosomes inherited from both parents.

Life, in a sense, depends on movement and exchange. It is sustained by continual transformation, from the vast journeys of migrating animals to the invisible traffic of molecules within a single cell. And even when an organism dies, movement does not immediately cease: molecules continue to interact, chemical reactions continue for a time, and the matter that once formed a living body remains part of the ever-changing natural world.

As my line of thought fades, I seem to come to a “no conclusion” conclusion… change is a fact, a truth we must come to terms with and, most importantly, believe rather than try to analyze and understand… yet here I am, analyzing it anyway. But how do we find a way to introduce this to our young ones, when it still keeps us up at night? How do we introduce a concept we still don’t believe and fight with every single day?

Written by Mariam K., PhD

Science Educator & Biology Tutor

References

¹ North Carolina State University Extension. "Eastern Gray Squirrel." https://content.ces.ncsu.edu/eastern-gray-squirrel

² de Raad, A. L., Balafa, F., Heitkönig, I. M. A., and Lurz, P. W. W. (2021). "Mitigating the impact of forest management for conservation of an endangered forest mammal species: drey surveys and nest boxes for red squirrels (Sciurus vulgaris)." Hystrix, the Italian Journal of Mammalogy. https://pure.uhi.ac.uk/en/publications/mitigating-the-impact-of-forest-management-for-conservation-of-an

³ National Geographic Education. "Monarch Butterfly Migration." https://education.nationalgeographic.org

⁴ NOAA Fisheries. "Humpback Whale Species Profile." noaa.gov

⁵ Lohmann, K. J., et al. (2022). "Magnetic maps in animal navigation." Journal of Comparative Physiology A.

⁶ Max Planck Society. (2026). "Pigeons navigate using magnetic sensors in their livers." Max Planck Institute of Animal Behavior. mpg.de

⁷ Lisowski, C., et al. (2026). "Homing pigeon navigation relies on superparamagnetic macrophages." Science. DOI: 10.1126/science.ady2486.

⁸ Schultz, G. S. (2011). "Principles of Wound Healing." Mechanisms of Vascular Disease. NCBI Bookshelf, NBK534261.

⁹ Janeway, C. A., Jr. (2001). Immunobiology: The Immune System in Health and Disease, 5th ed. NCBI Bookshelf, NBK10757.