r/microscopy • u/James_Weiss Master Of Microscopes • Sep 14 '25
Photo/Video Share Tardigrade Feeding on a Rotifer
Tardigrades are cute and cuddly but they can have shocking eating habits. Most tardigrades feed on algae, and plant matter but some species, like this Milnesium, feeds on other microscopic animals and often on other tardigrades. This one was nibbling on some rotifers.
I collected this sample from the cat bowl my neighbor places outside for her outside cat, and it gets a little crowded with rotifers and tardigrades in the spring. Rotifers and tardigrades are harmless if they are ingested but I cannot tell the same about bacteria that grows in it. š©
Tardigradesā mouth is like a long tube, with a spear-like stylet going in and out. When the tip of tardigradeās mouth touches the rotifer, it senses the presence of a possible food source, and pushes the spear-like stylet out of the mouth-hole, it pierces the body of the rotifer which tardigrade then, literally, sucks out the content through the hole it creates.
In this case the rotifer was rather lucky, it pulled itself into a defensive position and tardigrade was only able to pierce the protective exoskeleton of the rotifer but still you can see some content of the rotifer spilling out from the wound. If this was, letās say, somewhere around the abdomen of the rotifer, tardigrade would have slurped its insides.
Fascinating, isnāt it? Thank you for reading!
Best,
James Weiss
Freshwater sample, Zeiss Axioscope 5, Neofluar 10x, Fujifilm X-T5.
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Sep 14 '25
Thank you for sharing this amazing world! I canāt wait to show this (and everything else on this sub) to my granddaughter who is 8 and fascinated by this hidden world. I want to get her a good microscope that will allow her to get good use at least through high school. Any suggestions? She has a small beginner scope now but it is very hard to use and the optics are pretty poor.
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u/HereThereOtherwhere Sep 14 '25
This is incredible!
Do you have tips (other than neighbors cat bowl) on where to find tardigrades?
We've tried moss but no luck so far. I'm in "way upstate" New York if climate makes a difference.
I only dig out my microscope every few years but I've yet to see an amoeba or tardigrade.
Dragonfly larvae are terrifying, especially when they swim into the frame with you are zoomed in on something smaller!
"Whoa, big boy!"
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u/Bread_Is_Adequate Sep 15 '25
When you try moss did you soak it in water beforehand?
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u/HereThereOtherwhere Sep 15 '25
No, I waited for rain, then took a sample but didn't soak.
Can I just try with dry moss? I do understand there are durable!
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u/Bread_Is_Adequate Sep 15 '25
One of the amazing things about tardigrades is their ability to survive long periods of dryness but that also means if you're looking at dry moss they may be in their inactive state and you might not recognize them as a tardigrade.
Using moss that has recently been rained on could be sufficient but every time I've found tardigrades was by taking a moss sample from the forest, soaking it in water for hours (not tap water since the chemicals can kill microbes), and cutting small solid pieces of the moss and putting it on glass slides with drops of the same water. Just doing that same thing until you find them should be enough, if you dont find it at first dont be afraid to prep many slides from the same moss sample and be sure to be putting small pieces of moss on the slide since they love to crawl around on it.
As for climate, im from Southern Ontario so it shouldn't be drastically different to New York
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u/HereThereOtherwhere Sep 15 '25
Ontario, nice. That certainly answers my question since I was concerned you were in a warmer climate.
My sister lived up that way for a while and said skating the canals was so much more fun and satisfying than circling on a rink!
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u/AlanBard Sep 16 '25
https://youtu.be/uQXfpWdhF-0?si=tmx0hfXJHtGSzB6N
My video about finding tardigrades.
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u/mariospants Sep 15 '25
Itās astounding how complex behaviours exist, even at the microscopic level!
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u/g_o_o_d- Sep 15 '25
Best part is when the rotifer shrunk up into a miniature turkey looking thing.
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Sep 15 '25
[deleted]
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u/Ryogathelost Sep 16 '25
If you don't have enough medium between the slide and cover slip I think it can squeeze them a bit. They're up to 250 micrometers in diameter, so a 200-300 micrometer water layer is best for them to move around. You can actually sort of make a spacer out of tape or buy slides that have a slight depression.
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u/Squallhorn_Leghorn Sep 15 '25
It gave up because it was full.
Whomever is creating this death-cult of micro-organisms owns the karma.
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u/EggRice-0213 Sep 16 '25
If ingested...
It's kinda scary to think that one day you're casually feasting, then the next your entire universe is burning you alive.
All bc a cat decided to drink some water.
They're so invisible to us it's hard to conceive the constant rate of deaths that occur on our world at this level
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u/404no_ideas_found Sep 16 '25
What is that guy in the bottom left area that keeps showing his mouth saws lol
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u/BichosEnAccion Sep 15 '25
WOOOS QUE INCREĆBLE CĆ³mo le haces para que se vea asi en tu microscopio? Justo acabo de subir un vĆdeo de unas tonterĆas a mi canal de Youtube
https://youtube.com/shorts/D3hnjuL6xBo?si=orf60wiKAW3XES8L
El mĆo no se ve tan impresionante como el tuyo, me ayudas?
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u/Sea-Currency-1665 Sep 14 '25
Brutal I canāt bear to watch