What is the smallest animal that farts?

Factual Questions
1

A year ago, this question was asked:

I am asking this as something of a followup question.

(For the purpose of discussion, we’ll define a fart as a burst of gas expelled from the far end of the digestive system, whether or not said gas is explicitly generated as a by-product of digestion.)

Apparently, arthropods like cockroaches and millipedes are known to fart:

In fact, per the articles (both adapted from the same book), lacewings use farts offensively, farting on prey insects to stun them for consumption.

And not all animals with digestive systems fart, either — many fish fart, but octopuses don’t. Neither do sloths, or birds in general. So it’s not a universal phenomenon.

So … given this background, can we identify the smallest critter on Earth, defined either by mass or by physical dimensions, which can be said to fart?

P.S. An informational footnote, a fact I uncovered while googling this question — evidently sea lions have the stinkiest farts in nature:

2

Tardigrades are one of the smallest types of multicellular animals that have a digestive tract. I can’t find anything definitive on whether or not they fart, but the concept has been contemplated.

3

Your question brings up a dilemma. Is an amoeba (or other microscopic unicellular animal) expelling waste gas respiration, elimination, or farting?

In any event, googling “amoeba farts” brings up a startling number of hits (many of them regarding human farts caused by amoebas) and at least one illustration of the concept

4

In my high school biology class, the book called anything micro organisms expelled “excretion”. The book never went any FARTher in detail. :smiling_imp:

5

I can confirm. Some years ago in Astoria, Oregon, my wife and I walked by a pier with a bunch of sea lions on it. We were downwind, and OMG did they stink.

6

A bit of a topic diversion, but it’s distressing that with the mountains of Covid-19 research published thus far, we still don’t have a definitive answer as to whether the coronavirus can be transmitted through farts.

And does the virus itself fart? That would win the tiniest-creature-that-farts award. Unfortunately, electron microscopy prep kills living cells, so you can’t see them moving away from farting viruses with cries of “ew!”.

7

This Little Fella Has The Most Revolting Farts In The Animal Kingdom
Hilarious title for an article. Equally hilarious if it were a band name.

8

According to my dad, farts came from barking spiders. They must be quite small, since I never saw one.

9

Meh. Elephants are pretty big but every father knows they can squeeze under their sofa.

10

From my research, they fart in your general direction when threatened.

11

Can confirm. Monterey this year has been over-run with sea lions. They have taken-up residence right next to the walking/bike path beside the wharf, even taking over some benches. They are literally inches from you, and I am not sure it’s from flatulence, but boy do they stink!

12

So when we bake yeast bread, does it rise because the yeast is farting?

13

If so, then yeast farts don’t smell bad.

14

Arguably – within the limits of single-cell ambiguity I gave above.

Don’t let it bother you any more than thinking that when you’re drinking fermented beverages you’re basically drinking yeast piss.

15

But I bet they sound really cute.

16

I think it’s got to be valid - if there is a digestive process, and there is waste expelled in gaseous form, the only way it could be disqualified is that it doesn’t sound like a fart, but that can’t be right, because I can let one out quietly sometimes.

Yeast isn’t an animal though, but amoebae and probably some other unicellular things are - although having said that, some of the multicellular candidates might be smaller than the qualifying unicellular candidates - rotifers(multicellular) can be smaller than - and eaten by - things like Stentor(unicellular)

17

Single-celled creatures are by definition not animals.

18

And viruses are not living entities, so they definitely don’t fart.

19

Brown marmorated stink bugs.
The odor comes from the abdomen. I don’t if it’s really a fart.
But boy, they stink!

20

Sounds like we should start from finding the smallest animal–perhaps the one with the fewest number of cells.