Physical Discomfort Threshold For Pets
March 21, 2008 2:22 PM   Subscribe

What is the "baseline" level of physical comfort for a housepet?

When I say I feel "good" physically, I refer to the absence of pain or discomfort I experience at that moment: no headache, upset stomach, congested nasal passages, fatigue, itchy feet, dry skin, etc. But what about dogs, cats, and bunnies?

As somewhat heartier creatures than us in certain ways (they can eat raw or past-expiration-date meat, etc.), do housepets tolerate more physical discomfort, without recognizing it as such? Do they suffer from pain or discomfort that would register for humans as "not feeling well," even when they appear to be happy and in good health?

I'm not talking about a simple higher threshold for pain, or a lack of a way to express mild discomfort. Obviously, a dog scratches at an itch that it recognizes as "itchy enough to tend to."

I guess what I mean is, do we know whether animals take some measure of pain or discomfort for granted because they don't know any better? Are they only ever healthy and happy, based on the criteria I mention above, in a relative sense? Is Fido's definition of "itchy enough to tend to" way itchier than ours would be?

Yes, I'm throwing away my weekly question. I have the day off, it's a blizzard outside, and I'm just in that kind of pointlessly inquisitive mood :)
posted by Rykey to Pets & Animals (12 answers total) 1 user marked this as a favorite
Well, in practical terms, we measure the animal's happiness in terms of behaviour. We don't know if they're itchier than normal, we just know if they're scratching more than normal, etc.

I'm not sure how you'd measure itchiness (or pain, etc.) that did not cause a change in behaviour. But I'm not sure it matters. Unless they've been punished or rewarded for a certain response then I'd expect that their behaviour is a good indicator -- that is, if it doesn't cause a change in behaviour then it's not a significant change in itchiness/pain/etc.
posted by winston at 2:31 PM on March 21, 2008

The reason the sensation "itchiness" exists is to get the organism to respond to the cause of the itchiness. I can't imagine why we'd expect a non-scratching dog to be itchy -- what point would it serve?
posted by BaxterG4 at 3:00 PM on March 21, 2008 [1 favorite]

I sometimes wonder if having hands factors into this. My universe is so much more... graspable than my rabbit's.

Speaking of, I think a rabbit, in particular, will just sit there looking miserable while a human under the same stimulus would complain loudly and at length. Of course, I don't have any hard evidence, just watching their behaviour when they're back from the vets, and guessing how I'd feel.
posted by Leon at 3:09 PM on March 21, 2008

I'm not sure there is "knowing any better" as far as pain goes. Either you have the pain and endure (or don't, as the case might be), or you don't have it and marvel that you could possibly stand the pain. My perspective as someone with a comparatively low-intensity chronic illness - average people go, "Oh my goodness! How can you stand it!" at what I deal with, and I try very hard not to go, "Oh my goodness! How can you stand it!" at people who deal with more than what I have to put up with. Human tolerance is higher than what you might realize.

As for animals, just because humans can't read the cues doesn't mean the cues aren't there, and even if the cues aren't there, that doesn't mean they aren't feeling it. For example, I've been told that many declawed cats suffer back pain and semi-permanent spinal tension because without their toe-tips, they can't properly relax some of their back muscles. The way cat locomotion works, it's all tied together. Most laypeople can't see this, but it's treatable by chiropractors, and I've spoken to owners who say their cats have responded very positively to treatment. I once tried giving my aunt's very skittish declawed cat a backrub and she basically melted - that never happens.

Another example: fish. We fishkeepers love our finny friends, but there's a bit of a communication barrier there beyond what you might expect with a cat or a dog. Limbs and head tilts and vocalizations are useful for communication, it turns out. Bettas are smart enough to do tricks, but you can't really make eye contact because your head is 50 times their size, and it's your fingers they associate with food. As far as pain goes, many fish will act almost completely normal until they're on the brink of death, which is one of several reasons that there's the, "He was fine last night and now he's dead!" stereotype associated with fishkeeping. (The other being that fish often die because of basic neglect, so the fish wasn't fine at all, he just looked fine, you stupid ass. Do some damn water changes. Sorry, sorry, pet peeve.)

Anyway, I realize I didn't give a straight answer exactly - just some food for thought.

On preview - Baxter, you've never had an itch that you've ignored, not because you were forced to but because it seemed more trouble than it was worth to scratch?
posted by bettafish at 3:26 PM on March 21, 2008

(FWIW, carnivores can eat spoiled food because they have a different set up in their digestive system with a lot more immune cells. )

I think my dog isn't that different from me in her general amount of comfort. When she injured her leg a few months ago, she made a very low continual whine the first night until the painkillers kicked in. In the week or so it was healing, she was no longer whining, but I could tell her behaviour was different. She showed less interest in things she normally liked. She was restless about choosing a place to sit or lie down. It might not have been obvious to a stranger that she wasn't happy, but it was glaringly obvious to me.

In another example, when she had been caught out in the rain, though I felt guilty as all hell, she was her normal cheerful self as soon as I had towelled her off and run a blow dryer over her for a few minutes. I imagine she was exceedingly uncomfortable before I arrived home, but once the source of the discomfort was gone, she didn't seem to remember it.
posted by happyturtle at 3:32 PM on March 21, 2008

Response by poster: Thanks for the input so far; I know this is a strange question.

Since I'm no scientist, bear with me as I exhibit my ignorance (and stoopid terminology) here:
I think what would answer my question would be to determine whether an animal's "pain sensing" nerves were "firing" without obvious external signs of discomfort or decreased activity on the animal's part.

If the answer was "yes" with an adequate sample, we could say, "So, it seems that [species] often walk around with significant discomfort, even though it's not visible to us, and it doesn't seem to bother them too much either." And therefore, maybe, "People seem to attach a certain meaning to discomfort and pain that [species] don't, and so we respond with more urgency than they do."

Right? Or does physiology not work that way? Is the evolutionary essence of pain and discomfort in a species such that such stimuli would, almost by definition, elicit a behavioral response from the organism (what BaxterG4 is saying, if I understand him correctly)?

And on a more concrete level-- can anyone point me toward research in this vein?
posted by Rykey at 4:18 PM on March 21, 2008

I think people might have higher requirements for contentment. In order to be content my cats just have to be fed, not very hungry or cold, and have either me or the other cats around. For me to be content I need to have those requirements, but also some assurance that those conditions will continue into the future. If I don't think that my content condition will continue - for example, if I'm not sure I'll have enough money to buy groceries tomorrow, and therefore will be hungry - I won't be content.

I also think that people think more about their pain. If I have a slight pain in my leg I'll wonder if it'll get better, if it'll continue, if it'll get worse, how it happened, and what I can do to ease it. If my cat has a slight pain she'll probably just blow it off.
posted by christinetheslp at 4:20 PM on March 21, 2008

Best answer:
Pain is entirely subjective. It's mediated by attention, state of mind, meaning (in humans), level of opioids, etc. For example, you can have your arm ripped off in battle and literally not feel it because your body is putting tons of opioids out in order to get you out of the situation to somewhere safe, where you will soon start to be in agony unless someone gives you some morphine. The pain sensations are being generated that whole time-- but they aren't causing suffering because the opioids are preventing that, as can other neurotransmitters at various levels (ie, the spinal cord, not just the brain). This rapidly becomes complicated and philosophical because if pain signals are blocked before they reach the brain, is there really any pain at all?

So, you can't objectively measure pain in any creature because there is no objective to measure. This is why in humans you cannot tell someone who is faking from someone who is in agony. there is no "painometer" and there probably never will be because pain is processed at various levels of the nervous system and suffering is different from pain.

For example, one pain doc I spoke with had a woman who was in what she said was unbearable agony and it couldn't be relieved by mega-doses of opioids. When he questioned her closely, he realized that she thought this pain was a recurrence of her breast cancer and meant she was about to die. When he told her that the pain was normal age-related back pain, she suddenly didn't need any opioids at all because the meaning of the pain had shifted. This is not to say that she was "faking"-- it's just that when you think pain means death, it feels worse than when you think it's no big deal.

since pets can't anticipate death (as far as we know), this aspect is unlikely to affect them, but the opioids and other stuff about attention will. cats apparently have very high brain opioid levels, so they probably don't feel much pain generally, but it's hard to know.
posted by Maias at 5:16 PM on March 21, 2008 [1 favorite]

I think what would answer my question would be to determine whether an animal's "pain sensing" nerves were "firing" without obvious external signs of discomfort or decreased activity on the animal's part.

I suspect you will find much greater intra-species difference than inter-species. I've had dogs and horses that were 95% normal, bright eyed and happy even after suffering bad injuries and I've had ones that were the biggest babies imaginable and acted like they were dying because they stubbed their toe.
posted by fshgrl at 7:20 PM on March 21, 2008

Neither I nor anybody else has any idea how rats subjectively 'feel' about being in pain, but speaking as a former rat owner it may be an interesting data point that they absolutely refuse to show it - and will go to great lengths to hide it - until they are on the brink of death.

Presumably something to do with avoiding other rats who might eat them in a weakened state (this is also, again presumably, why a dying rat will spend its final few days frantically trying to get out of its cage).
posted by Ryvar at 9:09 PM on March 21, 2008

I've read somewhere the theory that while animals feel the sensations of pain as as "I", "A", "P", and "N", they really don't have the mental processes that would make make those individual sensations equal "PAIN". And they don't have the psychological impact of pain (reliving of past pain, dread of continued pain, fear of death, etc) that makes it so unbearable for humans, as in Maias cancer patient example.
posted by Theresa at 4:34 AM on March 22, 2008

One data point: My dogs skitter and jump head-first into walls, furniture, etc. and it doesn't seem to faze them at all. If I hit my head at similar speeds it would hurt a lot.
posted by Jacqueline at 7:50 AM on March 22, 2008

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