ELI5: The Surprising Anatomical Reason Why Rats Physically Cannot Ever Vomit.
Content Idea: ELI5: Why Can't Rats (and other rodents) Vomit?
Explanation: This is a great topic for an ELI5. The original poster already knows about the practical implications, like why rat poison is so effective, but they're curious about the underlying anatomical and physiological reasons. Many comments share this curiosity and try to explain it, touching on the esophageal structure, muscle strength (diaphragm), and neural coordination. There's also a bit of confusion about the difference between regurgitation and vomiting.
A compelling piece of content would simply and clearly explain:
- The Complex Mechanics of Vomiting: Briefly outline what needs to happen in an animal that can vomit (coordinated muscle contractions, specific neural signals, relaxation of sphincters).
- What Rats Lack:
- Diaphragm Strength/Function: Their diaphragm isn't strong enough or doesn't work in the way required to create the forceful expulsion.
- Esophageal Structure: A powerful muscular barrier (sphincter) between the esophagus and stomach that is difficult to overcome in reverse.
- Neural Circuitry: They lack the specific brainstem "vomiting center" or the neural pathways that coordinate the complex act of emesis.
- Why this is common in rodents: Mention that this isn't unique to rats but is common across many (if not all) rodents.
- (Optional but good) Evolutionary context: Briefly touch upon why this trait might exist (e.g., they evolved other mechanisms to deal with toxins, or the ability was never strongly selected for).
Target Audience:
- ELI5 Content Consumers: People who enjoy simple explanations of complex topics.
- Animal Lovers & Biology Enthusiasts: Individuals curious about how different animals' bodies work.
- Science-Curious General Public: Anyone interested in learning a fascinating biological fact.
- Individuals interested in "how things work": Specifically, those curious about the science behind common knowledge like rat poison efficacy.
- Students (Biology, Veterinary Science): A simplified explanation can be a good entry point or memory aid.
Origin Reddit Post
r/explainlikeimfive
ELI5 - Why can't rats throw up?
Posted by u/Much-Card3000•05/27/2025
I know they can't, as that's the entire reason that rat poison works. But do they just not have a gag reflex? What makes it possible anatomically for an organism to throw up, and what is it t
Top Comments
u/mlacuna96
You know, that makes me feel better about my shit head rats always stealing the treats I give them from each other. At least they have a good reason.
u/ITookYourChickens
Would make sense! Chickens don't really have much of a stopper between their crop and mouth, so if you accidentally squeeze their crop when it's full it'll come out of their mouth. Or if you'
u/CosmicallyF-d
And just to clarify in case people aren't aware that rat poison is not actually poison. It is often fiberglass mixed with anticoagulants. Cutting them on the inside so they bleed to death int
u/AnnoyedOwlbear
Ahhh, I can't help but wonder if you've found the evolutionary reason they can't there. Rats run hard, fast, and at multiple angles, can jump, swim, run upside down along things, and more.
u/ParsingError
They also really like to steal food from each other, and in fact prefer stolen food to not-stolen food. They are theorized to have evolved this behavior because if another rat is eating some
u/SexyJazzCat
Horses can’t vomit either, the reason for that is their esophagus gets blocked.
u/gulpamatic
This is very interesting! But I don't think that vomiting has anything to do with rat poison working or not. At least, not the kind they sell at my hardware store. Warfarin works by blocking
u/romanrambler941
So you're telling me the "garbage tester" position in Ratatouille is actually legit?
u/WoodpeckerSignal9947
Idk how relevant this is, but as a kid I knew horses couldn’t throw up since I was obsessed with learning about animals. Best friend’s family had a small herd, and we rode all the time. One t
u/SuperKing37
r/redditsniper
u/Anchuinse
Vomiting takes a combination of muscle strength and neural coordination. The first one is self-explanatory; if an animal (like a small animal that doesn't really run long distances or make lo
u/[deleted]
[removed]
u/canadianpaleale
It’s not just rats. It’s all(?) rodents.
A rat’s throat is long, and doesn’t have much muscle strength, so pushing food back out of their mouth is tough. Also, their brains don’t have the a
u/ryanoc3rus
They’re really good at making more rats is the tangent here
u/GIRose
Regurgitation is the evacuation of things in the esophagus, vomiting is the evacuation of the stomach and upper intestines.
If it's in the stomach, nonemeritic species can't get it out excep
u/amatulic
Yeah, my sister had pet rats, who were quite well behaved, enough that she would sometimes bring one to the dinner table, who sat on her lap or her shoulder or crawled into her shirt. Once th
u/nicknaklmao
the rat poison got 'em. it's a hard life for nonemetic species out here.
u/ITookYourChickens
*Oh no*
u/ArtistAmy420
Wait, so if they can't vomit but they can regurgitate which is somehow different, then why don't they just *regurgitate* the poison they can't vomit?
u/GIRose
They are extremely intelligent and social, if they come across new foods they will eat a tiny little bit, see if everything works out, and if they get sick they won't eat it again, and commun
u/GIRose
They have a really strong barrier between their stomach and esophagus, requires the diaphragm muscles to work independently which we have no evidence rats are even capable of, and they have o
u/ReduxRocketeer
So that’s why there are so many chicken themed pitchers. Art imitates life?
u/MrPsychoSomatic
Except through, as in *going through*.
u/ArtistAmy420
If it's this complicated, how did things evolve the ability to vomit in the first place?
u/SuperPimpToast
Please elaborate on this other method of dealing with poisons. Does it come out the other end quickly and violently? Do they have super livers or something?
u/charleswj
So can I use a chicken as a pitcher if I don't have one handy?
u/moametal_always
NGL, I didn't catch that.
u/fiendishrabbit
The entire rodent family lacks the ability to vomit. They have a strong esophageal muscle (that closes off the stomach) and their diaphragm is weak enough that it can't effectively push food