Cephalopods and pain?

[robyn]

Hi Everyone,

I was hoping some of our ceph keepers and/or scientists would be able to share their opinions on whether cephalopods can feel pain. Not only in the sense of perceiving noxious stimuli (presumably not in question), but also whether they experience the subjective 'emotional' component of pain.

I am interested in the adaptive value of pain-related behavioural changes, but pain is a difficult thing to measure in animals (and let me stress I am not planning to subject any cephs to painful stimuli in the near future, its mostly a theoretical interest for now).

Apart from the various conditioned-avoidance studies out there, I am curious to gather any reports of things like altered food-handling behaviour after tentacle/arm injuries (like avoiding the use of an injured body part), changes in exploratory or social behaviour after an injury, or changes in body patterning (perhaps more inclination toward camouflage) that might suggest recuperative behaviours indicative of ongoing sensations of pain.

Cephalopods are an interesting group to consider the adaptive value of pain for a couple of reasons. Firstly, because of their advanced cognitive abilities, it is possible that they may exhibit not only the sensory aspect of acute pain, but also some analog of its emotional component, something commonly assumed to be present in humans only. Secondly, pain is important to signal to animals that they are injured and need to either attend to a wound or protect themselves during the healing process. Given that cephalopods do not have the value of a social group on which to rely if they are incapacitated during a recovery process, ongoing pain that interferes with hunting may be maladaptive. Being prey-animals (in most cases), hiding outward signs of distress is adaptive, thus perhaps we might see clear physiological indicators of pain, but very subtle behavioural indications.

There are not many invertebrate pain models out there (most work is done on rodents), I would like to see more serious scientific study into pain perception in cephs, which might provide some impetus to see them covered by vertebrate-centric animal welfare laws.

 

[DWhatley]

Robyn,
I have wondered the same thing. Cousteau mentions (Soft Intelligence) that they used tourches underwater and that an octopus burned itself investigating the fire. They had to stop the experiment because the animal did not withdraw and was obviously burned. On the other hand, chemical sting reaction is well observed even in the home aquarium. I have noticed at least twice that my aquarium kept octos have protected regrowth on severed arms and, with the current briareus, would not leave the den openly until the severly truncated (2 to the webbing) arms were several inches long. The briareus observation is antecdotal at best and could have various interpretations having nothing to do with pain. Another observation I have made with two species (mercatoris, hummelincki) near natural death is the desire to keep to smooth surfaces. In several of my journals (I can dig up the links to the actual events this is a activity that interests your direction) I have mentioned that they would stay on the pumps, other pieces of plastic and most notably my hand. Again, this may be discomfort or it may be avoidance of being attacked by the cleanup crew before final death.

 

[spinycheek]

I wonder how one could think that animals are devoid of emotional pain, as it's so obvious in certain situations like losing a lifetime partner. Animals across many genera exhibit symptoms of loss, frustration, anxiety, etc. I do agree that true studies are important to provide a real foundation for this, but it just seems so obvious to me. It's like launching a study to prove to people that losing your eyes inhibits your ability to see.

 

[robyn]

Thanks D, that is just the sort of detail I was hoping for. Did you perchance notice any type of 'grooming' behaviour toward the injured limbs, such as might be required to keep the wound free from parasites?

Spinycheek, I agree with you that it seems counter-intuitive that animals do not experience the subjective component of pain, however it is incredibly difficult to show these things in a way that is objective - this is one of the reasons why animal welfare committees (and ourselves as scientists, I think) have problems with allowing such a notion as animals get further removed phylogenetically from our mammal-centric view.

Actually you provide a great example of why it is such a fraught issue in your reply - that animals exhibit symptoms of "loss, frustration, anxiety etc." - it is problematic for a scientist to conclude that a behaviour they observe is due to something like loss or frustration, because by necessity it requires us to project our own, preconceived notion of the animals' emotional state in order to make a conclusion about the 'meaning' of a particular behaviour.

 

[robyn]

I should probably clarify that I am interested in the emotional component of physical pain, not emotional distress as humans might experience from loss of a loved one or something similar.

An emotional (subjective) response to physical pain (or the likelihood of it being about to occur) are things like (and these are necessarily anthropomorphic) fear, panic, despair, depression etc. Like the unpleasant feeling you get recalling a painful experience, or the panic felt by some at the prospect of a dentist visit.

Very difficult to measure in animals, obviously enough.

 

[DWhatley]

Robyn,
Not really having anything in mind, my recordings and guessing are kind of scattered but I feel that observations at the moment rather than rememberences are closer to reality. My notes won't be anything really usable but might give you some ideas on things to observe.

I started recording that SueNami's extreme shyness (literally all other briareus have been more social much more quickly) and particularly her recluse behavior may have been arm related at post #18.

On Beldar's thread I recorded and remember thinking that touching seemed to be painful. She would voluntarily come to be petted and squish herself through my cupped hand on a nightly basis until just before and then after brooding (possibly discomfort from her swollen mantle pre-brooding). After her brood, she would come to my hand but barely touch and never came for petting. Pain of just confusion in sesenence?

OhToo (post 25) was perhaps the most convincing that octpuses are mentally stressed when not feeling well. He was going into sesenence and showed the typical eye infection issues that occur. Either from the infection or age (Bel started having trouble managing her movements as well), he could not keep himself off the bottom substrate for long. I reached in to put him in a net and he latched on to my hand so strongly I could not get him to release. Ultimately he started biting me when I tried to remove him. Once he was finally in the soft net away from the substrate, he quieted down and did not try to latch on to me again.

Post brood, Trapper (posts 37 and 47) would stay on the smooth surface of pump near the end, forgoing any kind of den. She seemed to perfer my hand to anything else and would settle there until I put her down. Her grandson, Wiley (post 22) showed the same desire to stay on the soft surface of my hand in his last days.

 

[robyn]

D, you're a star. thanks so much.

 

[DWhatley]

No, I am a hobbiest that can shamelessly anthromorphize . I do try to record what I see and then make my intreprations noted as an IMO in hopes that it give ideas to those who have the responsibilities to advance knowledge.

Scientific documentation of cephs being capable of mental anquish from pain would be a terrific study but I am afraid your social goals are loftier than the science considering that we (myself included) raise, slaughter and eat animals like pigs and cows (chickens don't count ).

 

[robyn]

well, my goals are not solely about animal welfare, I have a specific interest in the neurological bases of pain that are conserved across invertebrates and vertebrates.

 

[ckeiser]

Robyn,

Have you read Jennifer Mather's paper on Invertebrate Suffering? She has done a lot of great work in the field of cephalopod behavior and this paper includes discussion on octopus pain experiences.
Great inquiry, robyn, best wishes for your research.

I'll attach the paper for anyone interested.

 

[robyn]

That is an interesting read - I have had the pleasure of meeting Jennifer several times and she is a great repository of cephalopod knowledge. Thanks ckeiser

 

[gjbarord]

I love these topics and since I am in port I am glad I get to respond.

I may never understand our fascination with placing emotions on animals. Perhaps we are secretly lonely in this world and we must do this so that we can relate to others on our planet? I do not have the answer. In any case, I do not believe that even humans feel emotional pain as a result of direct physical pain. The emotions result after the pain is inflicted, sometimes a long time after. As cephalopdos, in this case, have been around much longer than Homo sapiens, I would think that any emotional pain would be selected against during the evolutionary process. What good would emotional pain do to a solitary octopus??

I have been having great discussions with Jim Cosgrove about human self awareness and how it relates to animals. We are different than other animals, for better or worse, and we do not all share the same characteristics. Why then are we always trying to coincide another species natural behavior to our inclined feelings of what that behavior means?

Dogs are cute, but are they really cute?? I just think that the their is a great distinction between Homo sapiens and other animals, again for better or worse, so why are we always trying to lift up animals to our standing; and why are they only animals that we can relate to? ie, octopus or dogs. Why not coral??

Emotional pain would only be a necessity in a society where altruistic acts were common. Solitary or short-lived animals such as cephalopods would have little use for a large energy expenditure such as emotional pain. Whenever I experience emotional pain from a physical pain it leaves me pretty weak and my only consolation is my attending girlfriend and a comfy bed. Animals with predators abounding have no such luxury.

Just my good ole two cents.

Greg

 

[ckeiser]

For a solitary species, yes, I think you might be right Greg. But the highly gregarious Sepioteuthis sepioidea, which has developed very intricate social rituals, may have evolved some form of "emotional" pain. Of course, any investigation into this kind of topic has a high likelihood of anthropomorphism and researcher bias/subjectivity, so we must be very careful.

I don't think we should jump to any conclusion (emotional pain or not) without the proper evidence on which to make claims. This being said, I do have a distaste for the concept of a human-animal dichotomous worldview. I, like Darwin and many evolutionary biologists before me, prefer to look at life as a continuous spectrum with our species right there along with our cousins.

 

[gjbarord]

ckeiser, well said but I would have to think that even Darwin saw the differences in each species even though every species is moving toward something which does not necessarily have to be an improvement. As much as I hate to say this, there is something inherently different about humans as opposed to other animals whether you are religious or not.

It would definitely be an intriguing study if one could control the various intangibles and researcher bias.

Greg

 

[DWhatley]

Greg,
Your lonliness concept has sent me on a thoughtful rabbit trail about why we want to believe there are other forms of intelligent life on other planets.