# Do inverts feel pain?



## johns (Jul 22, 2002)

Hi, I've been wanting to know whether or not a centipede, etc.. can feel pain stimulus or not.

My best guess is probably not, but seeing as how we have new members and old hats, I really'd like to know your best guess?


Thanks!


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## Code Monkey (Jul 22, 2002)

Of course they feel pain. The question isn't "do they feel pain?", it's "how do they feel about feeling pain?".

Almost any organism can feel pain - it's a survival mechanism. Pain isn't some mystic idea like enlightenment, it's a negative stimulus that hits you at your most primitive levels of your brain to let you know that whatever is causing it is not good.

Lest you ever think an insect or something similar can't feel pain, take a hot poker to one and observe its reaction - then try to tell yourself there's any doubt the animal feels pain.


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## MrDeranged (Jul 22, 2002)

I chose probably not, but I'm sure they feel something.  It may not be "pain" as we know it though.  It may seem to them more of a stimuli that they would wish to avoid and will move or take whatever action is needed to avoid it.  Not that they "feel anything" per se.

Scott


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## King_Looey (Jul 22, 2002)

Code_Monkey is absolutely right. All living things feel pain, its a primitive defence mechanism. I dont believe they feel the same kind of pain as we do. We have soft fleshy skin, whereas they have a hard carapace, but underneath they still have nerves to operate their muscles.


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## Unregistered (Jul 22, 2002)

"All living things feel pain"

Plants don't have nerves, if I remember correctly. Neither do sponges. Jellyfish have a very primitive nervous system, and might not feel pain either.

I imagine that tarantulas and centipedes probably feel pain, but I'm not certain. I personally don't know much about their neurological functions. 

I mean, I could stab a centipede with a red-hot poker and I would certainly get a response, but that doesn't necesarily mean that it is in pain. I also get a response blowing on my inverts, but that doesn't mean that it's painful to them.

But yeah, they probably feel pain.

whoami?


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## King_Looey (Jul 22, 2002)

How many of the above have a brain even remotely resembling ours? Tarantulas do, as do most insects.


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## Unregistered (Jul 22, 2002)

Actually, I was under the impression that spider brains are not very much like ours. I thought they bear more of a resemblance to the ganglia of something like a flatworm, for example. 

There's a bit of a difference between a primitive clump of nerves and a brain.

But hey, I may be mistaken. Maybe spiders do have true "brains." 

whoami?


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## krystal (Jul 22, 2002)

sure tarantulas feel pain.  just the other day i heard mine say, "ow."

pain is the response for danger, or, like code monkey so eloquently put it (i could read his entertaining posts all day  : )  ) "something's not right."  pain or hurt tells animals/insects/etc... to get away from whatever is causing said pain.  

and please don't argue that "pain" could be mistaken as "instinct."  i can debunk that theory by chasing around a tarantula with a burning remote control car.  i can almost guarantee that the tarantula (nor any of its ancestors) has ever been confronted with a flamin' remote control car, but it will still run away from it.

besides, what good is instinct without a reward or punishment effect to condition the response?


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## Code Monkey (Jul 22, 2002)

Krystal, that was a funny method of proving pain 

Some people seem to make the mistake of assuming that pain must be perceived exactly like our pain to be *pain*. I doubt very much an insect or tarantula feels pain in the same we do - their brains (and they are brains, I typed out a lengthy quote from the Shultz book detailing the anatomy on the old board that I won't bother to repeat right now) obviously conceive of the world and process the sensory information very differently. That still doesn't mean they don't feel pain and respond accordingly. One of the problems about being as "intelligent" as we naked apes are is that our brains have had to become more complex about basic things we'd be too stupid to manage otherwise. Avoiding negative stimulus is one of those things - the tarantula or cricket may not feel the searing discomfort we do, but they certainly regard the stimulus as inherently negative and attempt to avoid it every bit as much as we do; if that's not pain, I don't know what is.


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## Immortal_sin (Jul 22, 2002)

I believe they do as well...
Whatever type of 'pain' they feel, it elicits the same type of response...to get away from whatever is causing it.
I think if you have any kind of nervous system, there has to be some capacity for 'pain'.
There is my completely unscientific response 
And Krystal, how can you understand 'tarantula language'?!!
LOL....


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## krystal (Jul 29, 2002)

*i have proof...*

...that inverts do not feel "pain" the same way in which humans do. here's my proof: inverts, unlike humans, do not shove their fingers into their mouths—coupled with the obligatory "damn it!" curse—when they give themselves a paper cut.  pretty creepy, eh?  inverts are so ALIEN-like. 

just a little something to ponder whilst waiting for the bus or something....


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## el feo grande (Jul 29, 2002)

yep, every living thing feels pain, or some discomfort that can be discribed as "pain". 

el feo grande.


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## SkyeSpider (Jul 30, 2002)

As someone who has seemed to "master" the concept of pain, I'm fairly certain that inverts, as well as almost any creature, does feel pain. It is a universal sensation of negativity used as a reflexive defense against destruction of the body. Without that, survival is certainly not easy.

-Bryan

ps~ Please note that the attached image is NOT a tattoo  Just one of my many adventures into pain and the human psyche.


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## krystal (Jul 30, 2002)

bryan-

i have always been in awe when considering just how painful and traumatic a circle with an "x" through it could be to the human psyche!  thanks for putting it all into perspective!!  : )

(that's "smartass" for "ugh!  i can't see the picture you posted!")


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## whoami? (Jul 30, 2002)

I still say that it's uncertain that invertebrates feel pain. While pain certainly increases an animal's chances for survival, it is not the ONLY sensation that increases an animal's chances for survival. Like I said before, blowing on an invertebrate may cause it to take defensive measures to protect itself. But that doesn't mean that it hurts. It IS within the realm of possibility that an invertebrate could survive without ever feeling pain.

Also consider the difference between pain and discomfort.  Stab yourself with a 3" long needle, and you'll probably feel pain. Now try rubbing large-grained sandpaper lightly across your skin. It doesn't hurt, but it's certainly uncomfortable. 

Since there it is clear that pain is only a smaller set under the broader category of discomfort, I don't see how we can say that invertebrates DO feel pain. Some people say that invertebrates may not feel pain exactly as we do, but that they still feel pain. I disagree. Pain is defined by how WE feel it. Since we do not have first-hand knowledge of what it feels like to be an invertebrate, we cannot distinguish between an invert in "pain" and an invert in "discomfort" based only on its response. Take a razor blade to a tarantula, and it will obviously be in discomfort. But we still don't know if it feels "pain." Since we define things according to our own experience, if the tarantula doesn't feel pain in the same way that we feel it, then we can't really call it "pain."

And since we can't ever know exactly how an invertebrate interprets a negative sensation, the question of whether or not they feel pain remains open.


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## krystal (Jul 30, 2002)

for the sake of arguing semantics, maybe we should broaden the question to "do inverts feel anything?" which, unfortunately, instantly stupefies this whole thread and transforms it into an argument that measures up to no more than a piddle of redundant sophomoric philosophy.


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## Code Monkey (Jul 30, 2002)

The problem with that argument is you basically have decided a priori that they don't feel pain and then go on to justify it with a bunch of b.s. philosophy about how since we can't *know* therefore they must not. Further you make the very specious argument that to be pain it must be equivalent. Sorry, go steal a mother dog's puppies and tell me that her loss is not equivalent to a human mother's just because the dog isn't fully sentient and can't conceive of all the wondrous nuances of loss that we can.

We're fully aware, this makes us among the most clever and stupid animals on the planet because we're conceited enough to believe that sentience does us much good in most situations. As a result our *conception* of most sensory data gets a lot of human flavours associated with it.

All empirical evidence says that most inverts will react with the exact same behavioural responses to you or I about pain. Just because their *conception* about it may be completely different doesn't mean it isn't still pain. If you want to change the argument to "Do inverts feel pain in exactly the same way as humans?" then I'd argue no.

OTOH, I don't think your average Ultimate Fighter or body piercing afficianado feels pain exactly the same way I do either, so I guess by your reasoning I can conclude that they don't feel pain either


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## whoami? (Jul 30, 2002)

"The problem with that argument is you basically have decided a priori that they don't feel pain..."

Uh, no. That's not at all what I was saying. I was saying that we don't KNOW whether or not they feel pain.

"...and then go on to justify it with a bunch of b.s. philosophy about how since we can't *know* therefore they must not."

Did you read my post? That's not what I was saying, either. I was saying that since we can't *know*, therefore we...uh, don't know.

"Sorry, go steal a mother dog's puppies and tell me that her loss is not equivalent to a human mother's just because the dog isn't fully sentient and can't conceive of all the wondrous nuances of loss that we can."

You see, EMOTIONAL pain is dependent on knowing the nuances of loss. If it can't conceive of the nuances of loss, then the feelings of loss are necessarily diminished.

"We're fully aware, this makes us among the most clever and stupid animals on the planet because we're conceited enough to believe that sentience does us much good in most situations. As a result our *conception* of most sensory data gets a lot of human flavours associated with it."

Yes, true. And then there's also the fact that we can only have direct experience of our OWN senses. Ask yourself, "what is pain?" You can only define it in terms of what YOU can feel. And along with your definition, you start to think about how you respond to pain. Now, you cannot know what other creatures "feel", so you must make an educated guess based on how they respond. For example, you decide that, in your experience, screaming is a sympton of pain. Now you decide to stab a cat with a steak knife, and it immediately screams. You can assume that it is in pain. But, in my experience, invertebrates are relatively non-expressive. Regardless of whether or not they do feel pain, they don't give us enough evidence for us to know that they feel pain. Break a cricket's legs off, and it MIGHT hurt. But we'll never know, since they don't show it. Furthermore, they tend to react to supposedly "painful" stimuli the same way that they react to stimuli that are merely "uncomfortable." Pick a cricket up and cut it with a razor balde, and it does exactly the same thing as if you were to just pick it up: it tries to get away. 

"All empirical evidence says that most inverts will react with the exact same behavioural responses to you or I about pain."

No, I just briefly discussed this. Unless the response that you're referring to is simply "trying to get away from whatever is causing the 'pain.'" But they act the same way towards non-painful (to us) stimuli such as being blown on. I think that trying to avoid something is not sufficient evidence for us to say that it is painful.

"Just because their *conception* about it may be completely different doesn't mean it isn't still pain. If you want to change the argument to "Do inverts feel pain in exactly the same way as humans?" then I'd argue no."

Are you talking about what they THINK about pain? Physical pain is independent of what we THINK about it. You can still be in tremendous pain, although your thoughts might be somewhere else entirely. I am fully aware of this, which is why I am willing to admit that there is a possibility that invertebrates feel pain.

"OTOH, I don't think your average Ultimate Fighter or body piercing afficianado feels pain exactly the same way I do either, so I guess by your reasoning I can conclude that they don't feel pain either"

In a way, you are correct here. Some people are more sensitive to some things than others. What may be painful to me might not be painful to you. Of course, all humans very similar to each other, so we can usually assume that what hurts me will also hurt you. Some might say that arachnids and humans share enough similarities that we can make the same assumption, but I just happen to disagree. And in any case, if I'm in doubt about whether or not the UFC fighter is in pain, I'll just ask him.

This whole question seems a lot like asking whether or not God exists. Some people will say no. Some people will say that they don't know. Some people will say yes. But the people who say yes are generally the first to fling accusations of being conceited and narrow-minded. Well, why not just throw the insults out the window and try to PROVE that I'm wrong? If it can't be proven, then we have no way of knowing.


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## Code Monkey (Jul 30, 2002)

One obviously cannot prove what you ask (you cannot prove a negative issue without a lot of other related proofs). Even if a cricket felt pain 100X times worse than you we can not argue nor certainly prove anything about what it feels until we can share language and concepts with one another and that's not happening with your average invert.

BTW, do you read insect pheremones and chemical signals, monitor internal pressure, hear at ranges outside of normal human hearing? Didn't think so. Trying to argue that cutting a cricket with a razor blade and picking it up are identical is a silly argument at best - you lump a gross motor action with a similar gross motor action and declare the two total reactions the same. With that same sort of glossing over you could claim the reaction of me hitting you with a 30grit sander and a chainsaw are identical if I don't happen to think the screaming versus yelling profanity is different enough to pay attention to.

The reason I react to the "We can't know" argument is that in this case, as most, it's a justification to hang onto a premise in the absence of any evidence to the contrary. Pain is primal nervous stimulus and isn't more than a variation on discomfort anyway. Like I said early on, you make the mistake of assuming that pain must be *conceived* the same way as we do to be pain and I think that's a patently false premise. I don't know that an invert feels pain in the same way I do, nor do I care, I know it still feels pain. We didn't start out human as a species, we started out as spineless things as well - the same basic mechanisms drive us as drive almost all living things - pain didn't just magically appear when the first notochord became a spine.


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## whoami? (Jul 31, 2002)

"One obviously cannot prove what you ask (you cannot prove a negative issue without a lot of other related proofs). "

Except I'm not asking you to prove a negative issue. I'm asking you to prove a positive issue, which is that invertebrates DO feel pain. Of course, despite the fact that it is of a provable form (because it's an existential positive), your claim is of such a nature that it's not likely to be proven or disproven. You've still done absolutely nothing but give me your opinion. If you have any evidence, something measurable and independently verifiable, I'f like to hear it. Otherwise, your opinion is no more valid than my claim.

"Even if a cricket felt pain 100X times worse than you we can not argue nor certainly prove anything about what it feels until we can share language and concepts with one another and that's not happening with your average invert."

Yeah, that's my whole point. We don't know whether or not they feel pain.

"BTW, do you read insect pheremones and chemical signals, monitor internal pressure, hear at ranges outside of normal human hearing?"

What do you think?

"Didn't think so."

Ah, good. That shows that you're actually thinking. Keep it up.   

"Trying to argue that cutting a cricket with a razor blade and picking it up are identical is a silly argument at best..."

Ooh, he's gonna tell me why! I can't wait! 

"...you lump a gross motor action with a similar gross motor action and declare the two total reactions the same."

The same as I see 'em. They might be completely different. One motor action, but not the other, might involve "negative spirit energy" or any manner of new age mumbo jumbo. But I obviously have no reason to comment on that stuff. I see your point, though. I just think that you're spewing nonsense. You see, your previous statement implies that SOMEBODY has monitored pheromones, internal temperature, etc. If so, then please show me a link or something. Since my position largely depends on arachnids being unexpressive, you could potentially prove your claim by showing internal changes and showing that the are always (and only) linked to stimuli that are known to cause pain in the "higher" organisms. But I don't think that you are privy to such data, either. I think you're just throwing out "what-ifs" to try to hold on to your opinion.

"With that same sort of glossing over you could claim the reaction of me hitting you with a 30grit sander and a chainsaw are identical if I don't happen to think the screaming versus yelling profanity is different enough to pay attention to."

Yeah, except you actually NOTICE that there is a difference. If you find arachnids equally expressive as human, behaviorally and chemically, please write a book on it so that I gain learn from your vast knowledge.

"The reason I react to the "We can't know" argument is that in this case, as most, it's a justification to hang onto a premise in the absence of any evidence to the contrary."

This may come as a surprise to you, but there are quite a few things that we don't know. And the only premise I'm trying to hold onto is that "we don't know." My evidence for my claim is that, well, "I don't know." I mean, JFC, why is this so hard to understand? Anyway, the burden of evidence doesn't rest with me, since I'm not the one making a claim about nature. Since YOU'RE the one making a particular truth-claim about nature, the burden of proof rests with YOU. And, if I remember correctly, you already said that you can't prove it.

"Pain is primal nervous stimulus and isn't more than a variation on discomfort anyway."

Maybe, but they certainly do share similarities. Pain is uncomfortable, is it not? That's pretty much all I was getting at. But just for kicks, feel free to inform me on the neurological differences between perceiving "pain" and "discomfort." Who knows, it may even help your argument.

"Like I said early on, you make the mistake of assuming that pain must be *conceived* the same way as we do to be pain and I think that's a patently false premise."

So we disagree. If it doesn't "feel" the same, it may or may not be pain. Call it whatever you want, but "pain" is defined in terms of how we conceive it, since we can only have direct knowledge of how WE conceive it. I'm not saying that they don't feel anything equivalent to pain, just that it isn't "pain" if it isn't as "painful." But that's kind of a moot point since, as we've both acknowledged, an arachnid's sensations are not subject to direct measurement.

"I don't know that an invert feels pain in the same way I do, nor do I care, I know it still feels pain."

Okay, I'll bite. I'll just ignore the difficulties with terminology for the moment. Now all you have to do is come up with some hard, measurable data, and you'll have proven your point. Please, go ahead. I'm waiting.

"We didn't start out human as a species, we started out as spineless things as well..."

Well, technically that wouldn't have been "us," but I guess I shouldn't complain about every little thing you say.

"...pain didn't just magically appear when the first notochord became a spine."

Most likely. But since you have all the answers, why don't you tell me exactly WHEN pain appeared? 

You see, we don't KNOW when pain appeared.

And this is really getting boring. Until somebody can provide any actual evidence that arthropods feel pain, I'm not wasting any more f my time on this thread. In the unlikely event that somebody DOES provide evidence to support or claim, I'll either dispute their evidence, admit that I'm wrong, or something in between. Whatever is appropriate, given the evidence. But before I go, I just want to look at one thing that CM said:

"One obviously cannot prove what you ask "

Can't prove that they feel pain, then your claim that they do is nothing more than opinion.

And that's all there is to it.


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## johns (Jul 31, 2002)

Hi, Code-

Glad you found some use for the invertebrate pain articles I sent you!


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## johns (Jul 31, 2002)

Whoami, 


You're absolutely right about Code Monkey's "opinion" about nocioceptive response in inverts, for that's exactly what it is- an informed opinion.

May I suggest reading the article;ILAR News Vol 33(1-2) 
... morphine-induced thermal response in the terrestrial ... and naloxone on a defensive response ... Ethical
Treatment of Invertebrates: How do ... on the recognition of pain ... 
http://www4.nas.edu/cls/ijhome.nsf/44bf87db309563a0852566f2006d63bb/7e63cb4f4c3f9982852568dc005243a8 


Sorry:8o: I still don't  know how  to use links!


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## whoami? (Jul 31, 2002)

Thanks, johns! 

This is more along the lines of what I was hoping for: that is, results from actual experiments. This article really doesn't seem to settle the issue one way or the other, and I am still left thinking that we just don't know whether or not invertebrates feel pain. Throughout this article are several issues brought up by Code Monkey and myself, and it's good to see them presented together with support from hard data. I must admit, though, that I failed to consider cephalopods, which are a more convincing (if uncertain) example of invertebrates that PROBABLY feel pain. Still, there is some dispute about the cephalopods, and arthropods are generally considered even "lower" organisms. So I obviously am not convinced that our beloved tarantulas feel pain either. But here's an interesting quote from the article:

"Although pain might seem less likely in the more "simple" invertebrates, than in the most "complex" invertebrates, such as the cephalopod mollusks (and, perhaps, decapod crustaceans such as crabs and lobsters, not considered here), this certainly does not mean that the more "simple" invertebrates ought not to be afforded respect."

Throughout this discussion, I thought I sensed this issue lurking below the surface, and thought that it might have been the cause of some kneejerk responses against me. As an invert owner, I can understand this and I definitely agree. To say that invertebrates don't feel pain makes them seem more "alien,"and thus expendable to us. We as a species are most respectful of animals that are like us, and for that reason I can understand wanting to think that invertebrates feel pain, if it has the effect of making them more tolerable in the public eye.

Still, I cannot in good conscience say that they DO feel pain when the issue remains unresolved. Truth-claims about nature DO require hard evidence, and absent evidence, those truth claims need to be either discarded or put on hold.

Later.


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## MatisIsLoveMantisIsLyf (Jul 28, 2017)

I've tried hitting a fly against the wall multiple times, she seemed ok. The thing is, they dont have bones on the inside, and their neurons are limited, so they most likely dont feel pain


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## LawnShrimp (Jul 28, 2017)

Hate to break it to ya but nobody's posted here for 15 years.

Reactions: Like 1


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## MatisIsLoveMantisIsLyf (Jul 29, 2017)

yeah i know but i still replied XD


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## 7Fin (Jul 29, 2017)

They're built with nerves made with sensors to create pain, just like us. I think that they feel pain, pleasure, distress, fear, and relief just like we can, maybe not as deeply as we do, but they feel it.


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## Whitelightning777 (Aug 3, 2017)

An animal that didn't feel pain would be at such a huge disadvantage that it certainly would not have outlived the dinosaurs!!

Whether or not they have memory or can even learn at all is a far more interesting question.


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## schmiggle (Aug 3, 2017)

Whitelightning777 said:


> Whether or not they have memory or can even learn at all is a far more interesting question.


They can and do. But even flatworms can learn. Flatworms in particular continue to store memories even after being decapitated.


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## TylerFishman5675 (Aug 4, 2017)

Invertabrates are nothing more than machines with primitive nervous systems and hemolymph, arthropods are entirely instinct based, think of you pulling your finger away from a burning stove that kind of instinct, think about how monarchs migrate to Mexico, or how ants will kill their own mother if they find her unfit,  entirely instinct  arthropods do not have emotion and emotions are typically what exacerbate pain and make it such a debatable topic, insects dont feel emotion, if you raised a tarantula from a sling, sure it may tolertae you somewhat more but it wont hesitate to try and injure you just for opening the lid on its container or running in fear of predation even though its just what feeds it every few weeks, its fun to anthrpromorphize our invertabrate pets and think they have seprate personalities that are entirely distict and unique in their mannersisms, but they truth is they are just following whats inside them


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## johanliam (Aug 6, 2017)

I think they do feel pain. Their neurons are smaller but still functions just like ours, just a lot less steps behind. they can even be trained. Check this out, 



_______________________________________
Pest Control DC


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## TylerFishman5675 (Aug 6, 2017)

johanliam said:


> I think they do feel pain. Their neurons are smaller but still functions just like ours, just a lot less steps behind. they can even be trained. Check this out,
> 
> 
> 
> ...


The fly is not trained it is simply trying to get to higher,  safer ground, all insects can do this.


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## mconnachan (Aug 6, 2017)

Unfortunately these are questions and answers we will never know, we all have opinions whether right or wrong, we can only guess whether these animals feel pain - however if a spider were to walk onto a hot surface for instance I can assure you it would feel the heat and therefor remove itself rather quickly, do you think it would stay on the hot surface and let itself become burned....you decide.
I know what my spiders would do!


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