Now the physical stuff... All that witch-hunting stuff has the assumption that Changelings process air in the same way as a pony. Insects not only use tubes all through their bodies, but also have issues with too much oxygen and don't breathe for minutes, hours, or even days, apparently. But the main reason I think insects are so different is their small size and the scaling of surface area to volume and all that - which means that a lot of stuff bugs do wouldn't work at larger scales at the size of a changeling. Heh, so here's some experiments to run...

1. Cold or hot-blooded?
Simple: in a cool room, do they maintain body temperature?

2. Trachea tubal system, or lungs and one trachea?
a. If lungs, they should be able to blow air in and out just as hard as a pony of similar health without moving their cheeks.
b. If tracheal tubes, covering nose and mouth will not cause breathing problems, if lungs, it will.
c. If lungs, covering entire body except mouth will not cause breathing problems, if tubes, it will.
d. If you can't feel any holes, neither can air. If the skin feels smooth, then there can't be any working tracheal tubes in it.

Finally, they may be able to hold their breath for days, but 2.c. can just last an uncomfortably long time...

So, in other words, if they used tracheal tubes then you'd be able to tell.

And 3. Exoskeleton or Endosekelton?
An exoskeleton would make them immune to constrictive choking, but if you can pinch some fat on their arm or squeeze their wrist, then that proves no exoskeleton. While I don't know much about tracheal tubes, I do know that exoskeletons for sure aren't viable at the size of, say, a cat, since everything needs to be closer to an "anchor" - which in larger animals' case is their endoskeletons.

So in pony form, they must be pony enough for the tests to work.

But, scientists only recently discovered they can hold their breath for days, and who knows how much the ponies may or may not know about changelings - and changelings aren't [i]actually[/i] bugs, so who knows how much of that even applies even in bug-form. But at any rate, it seems inevitable that you'd either be able to feel past illusion magic, or the hanging thing would work.

If they don't drop more than a few inches they should be almost completely safe from anything breaking. If it cuts off blood flow to the brain, unconsciousness will take seconds, otherwise maybe a minute or two. Whether asphyxiation or blood flow restriction, the end result is hypoxia, insufficient blood flow to the brain causing unconsciousness, which would hopefully knock the disguise out just as surely as whacking them. It's all kind of a blur of probabilities, but it's like a few seconds to minutes to unconsciousness, then there's a few more minutes or 20 before permanent brain damage starts occurring, then death. Big question mark on how much physicians or curious scholars (or writers who care about accuracy, hah) know at the time, but if the Bat pony regime is terrible enough to warrant a revolution, then they probably know quite well unless they use some other method.

Then there's also ether and/or alcohol. By the 1850's chloroform and Diethyl Ether were both starting to be used as anesthetics in surgery, so there's a much safer route to unconsciousness. Alcohol, of course, was known to be able to knock people unconscious (relatively safely) long before that... But honestly, the margin in-between knocking someone out and killing them with chloroform or Diethyl Ether is pretty narrow, so either alcohol or asphyxia might be preferable if there's no doctor.

But who knows if they know how changelings even process alcohol. Though something like that would definitely be a lot less PTSD-inducing...

- Oh, right, and of course limited flying abilities; while changelings can hover (and do so carrying much more than their weight), would be a much safer test if you believe - if the disguise were true - they would be unable to hover. So the question was, did Canary rely on wind because she was new at it, or do they all not know that pegasi can hover? But if they're willing to bet that Canary couldn't (if she somehow survived!) then difference in flight ability could work. Though booze is a less traumatic and cruel option, if they believe Changelings can get drunk, and will believe the person when they act drunk... and pass out.

Dang, it's creepy how much I know about this stuff. The stuff you learn as a writer :twilightblush: Though it's nice to learn creatures are a bit more hardy than most people think, and no, space won't make someone instantly freeze or explode or anything super dramatic. 2001 actually got it right - a vacuum would be very unomfortable, but you could take it for 10-15 seconds before passing out (1. don't hold your breath since the pressure difference in-between the lungs and space will force the air out in a boom that carries enough force to collapse lungs, and 2. it's much shorter than you can hold your breath because the lungs are designed to let air across the boundry into blood, but in a vacuum it works in reverse and the oxygen outgasses into the vacuum. Which also has the advantage of no Co2 buildup - your body doesn't panic at loss of oxygen, it panics at buildup of Co2 - so a vacuum actually doesn't create that sensation or cause a spike in blood acidity, but of course the lack of oxygen is a problem...)

And that's like 30 minutes writing that that I should've either been spending on today's to-do list or responding to your FB message :facehoof: My fault, my fault, sometimes I get my head too deeply "in the game" and get really interested in solving a problem with a high degree of certainty in a fictional world, hah.

We can solve all the world's problems... With SCIENCE!

...Well, maybe not all of them, but a great many of them, at least. We can at least learn how to tell changelings from ponies... and perhaps with some experimentation do it without giving innocent ponies PTSD or making them play a dangerous game of Russian Roulette with the odds. Certainly preferable to certain death, though.

...Huh, I wonder if they could do something with drawing blood. Again back to the bug-like question - if they're very bug like, it might be very different from mammal blood - maybe not the color, but the properties might be able to be discerned in a lab of even early 1800's tech, perhaps. But again, the open blood circulation system insects use only works at tiny sizes, and I'm not sure how many of the blood differences have to do with that. But if you draw some blood from the suspect, then when it's removed does the spell no longer continue to act on it since it's separated from the changeling? What if you carry it miles away?

Or heck, how about hairs? Cut some hair. Changelings seem to have fin-things, not hair, so if you clipped some and carried it miles away, can you carry it out of their spell's range?