Croc the Ciliate and the Little Green Heart

a Microbial Fairy Tale

by Wim van Egmond, the Netherlands


Once upon a time there was a small cubic millimeter, situated in a freshwater pond. It was a pleasant microhabitat near some strands of filamentous algae overlooking a nice plankton rich water column. One of this cubic millimeter's inhabitants was a voracious Ciliate called Uroleptus. All his neighbours called him 'Croc' because of his enormous mouth-region, equipped with a majestic adoral zone of membranelles (AZM). It made him look very crocodilian and his appetite added to the resemblance. The favourite meal of this ciliated villain was algae and especially the small flagellated forms.

Once upon a time, only just before the once upon of the time this story began with, there was a tiny flagellated alga called Phacus. This particular alga was not just an alga. It was a very special alga. His friends called him Little Green Heart and not only because his body shape resembled a little heart.

This little microbe was the kindest, and most good hearted single cellular life form you will probably ever meet. Life was good for him. The Little Green Heart was fond of travelling. Propelled by his whip like flagellum and guided by his little red eyespot he could swim towards the light and spend days just below the water's surface. All he did was basking in the sunlight to perform photosynthesis. Little Green Heart could lead this peaceful life because he didn't have to look for food. All life's resources where there: light and nutrient rich water.


Unfortunately, as in every well respected fairy tale, this happy life could not continue for ever. Croc the Ciliate would not be Croc if he wouldn't spoil the Little Green Heart's happy life.

With a very special type of photography, called photomicrography, which means photography through a microscope we can show you what happened during that most dreadful once upon a time.


Croc the Ciliate was doing what he was usually doing, feeding on small algae. He used his membranelles to sweep in as many algae as he could. One after another they were swept in. But suddenly the Croc stopped feeding. He had spotted a very special meal and it was something he had not eaten before.

The Little Green Heart swam for his life but his flagellum was not powerful enough to outswim Croc who had dozens of cilia. The Little Green Heart realised that his life was not going to last long.

The next thing that happened was so gruesome that it is not easy to describe. It was actually such a horrible sight that there are no pictures available either. When the Little Green Heart was devoured by Croc the Ciliate nobody dared to watch, including the photographer.

All we can do is give an exact account of the last words that were heard. The final conversation between the Little Green Heart and Croc the Ciliate.

"Good day and a pleasure to meet you! May I introduce myself, I am the Little Green Heart."

"I am Croc and it is a pleasure indeed because in a very short time I am going to eat you alive!"

"Oh no! Spare me!"

"For certainly not, you are my dinner! You look like dinner and I am pretty convinced that you will also taste like dinner!"

"But why feed on me? What have I done wrong?"

"Nothing! It is simply your destiny that you will be eaten. And it is my destiny that I'll have to eat you."

"I guess I can't change your mind. Then I must warn you of the consequences. Listen to my words! If you'll eat me, you will not only break my heart, it will tear you apart as well!"

"I can't say that I care much! I'll take the risk! For destiny's sake!"

- Engulph -


You may expect that after this gruesome event life would continue as if nothing had happened. And perhaps life did continue as it had always done.

But the images below clearly show that the Little Green Heart had spoken the truth and that his prediction became reality. Only minutes after the Little Green heart departed its own life and became a part of the Croc, the Croc itself broke apart. You may think it is coincidence, you may think it is made up, you may think it is binary fission, the Croc surely fell apart.


And that was all. Nothing else happened. Life continued as usual. Days were followed by nights, nights were replaced by days, only this time without the Little Green Heart.

Was that truly the end of the story? That's not a satisfying ending for a fairy tale! But don't forget this is a microbial fairy tale and in the microworld everything is different from the big world. It could be that the microscopic world is a world without happy endings. It is just a matter of how careful you observe this world of the small. Which magnification you use, which illumination. Every time you look through the microscope you will see other details. If you are a really good observer you would be able to notice that something had changed.

It could be just imagination

but if you looked really closely,

it was just as if Croc's look at life was different than before.

as if he saw everything brighter and greener,

through coloured spectacles.


And he lived even more happily ever after than before.


No animals were harmed during the making of this article.
Comments to the author Wim van Egmond are welcomed.

Visit the Micropolitan Museum

Microscopy UK Front Page
Micscape Magazine

Article Library

all material Wim van Egmond

Published in August 2006 Micscape Magazine.

Please report any Web problems or offer general comments to the Micscape Editor.

Micscape is the on-line monthly magazine of the Microscopy UK web site at Microscopy-UK Ltd, Microscopy-UK, and all contributors 1995 onwards. All rights reserved. Main site is at with full mirror at .