Image credit: Giovanni Handal via Wikipedia
This Easter I visited one of my cousins and, as is tradition for a lot of people this time of year, we had a crawfish boil. Eating boiled crawfish (crayfish for you non-Cajuns) is an ever present activity in southern Louisiana, at least when they’re in season, and I’ve had my share over the years. Although for me it’s a mostly social thing because I can take or leave crawfish as a food.
Anyway, it had been a while since I observed the actual cooking process. When the squirming wriggling mass of crawfish are lowered into the boiling water, I’ve always had a moment of dread and mortification, wondering how much these creatures are suffering in their final moments. And how long they remain alive in that pot.
When I was a boy, I mentioned this once or twice, and was teased for it, both by adults and other kids, for essentially being concerned about the welfare of “mud bugs.” At the time I accepted this as a correction for attributing too much intelligence and feelings to these creatures. But the disquiet each time I saw it never went away, although I eventually learned to keep my mouth shut.
In retrospect, after seeing other kids get the treatment over the years, I now see the teasing as a defensive reaction. No one wants to consider that we may be subjecting these creatures to unconscionable suffering. Far easier to conclude that they have no real sentience, and to squash any sentiment that they might, particularly in kids who might go on to ask difficult questions.
Pain in crustaceans such as crawfish, as well as invertebrates overall, is a difficult issue. The evolution of vertebrates and invertebrates diverged from each other long before central nervous systems came along, so many of the structures we associate with cognition and pain are either radically different or missing.
Even in vertebrates, we have to be careful. Vertebrates have specialized nerve cells throughout their peripheral nervous system called nociceptors, which are sensitive to tissue damage. Signals from these nociceptors are rapidly relayed to the spinal cord and brain, where it usually leads to automatic responses such as withdrawal reflexes or avoidance behavior, as well as changes in heart rate, breathing, blood pressure, and other metabolic functions.
But, as counter-intuitive as it sounds, nociception by itself is not pain. Pain is a complex emotional mental state. Neurological case studies show that in humans it happens in the forebrain, the thalamo-cortical system, where the right kind of lesions on pathways to the anterior cingulate cortex can knock it out. This means that the processing happening in the brainstem is below the level of consciousness, and that the behavior associated with it, when seen in other species, is not by itself an indicator of conscious pain.
This is an important point, because a lot of the material out there confuses nociception with pain, citing things like protective motor reactions and avoidance behavior as evidence for pain. But pain is a higher cognitive state. To establish that it’s present requires demonstrating that the animal can engage in nonreflexive operant learning and value trade off reasoning.
All vertebrates appear to display at least incipient levels of this more sophisticated behavior, indicating that all vertebrates feel pain. Although in the case of fish, many species are missing a type of nociceptive fibers, c-fibers, which transmit the signals that lead to the long burning type of pain associated with prolonged suffering. These fish appear to suffer the sharp pain when an injury is incurred, but not the long burning pain that land-animals experience.
However, nociceptors haven’t been found in most invertebrates, either of the fast sharp variety or the long burning kind. This has led many to conclude that they don’t feel pain. However, many invertebrates do show some reflexive reactions similar to the ones associated with nociception in vertebrates, which seems to show they have alternative interoceptive mechanisms for accomplishing similar results.
Perhaps a more difficult issue is whether they show any signs of the cognitive abilities required for pain in vertebrates. Todd Feinberg and Jon Mallatt, whose book, The Ancient Origins of Consciousness, is my go-to source for this sort of thing, lists crayfish as demonstrating global operant learning and behavioral trade offs.
Following the citation trail, the paper that reaches this conclusion shows that crayfish, while having a pretty limited repertoire of behaviors, can nonetheless inhibit reflexive responses, and change responses depending on value based calculations. This is pretty much the same capability in vertebrates associated with the capacity to experience affective states, such as pain.
That would seem to indicate that the crawfish, while possibly not experiencing pain as we understand it, nonetheless are in distress.
I read somewhere that lobsters being boiled can live for up to three minutes. (The experiments to figure that out can’t have been pretty.) Hopefully, crawfish, being smaller, die quicker. And hopefully they lose consciousness quickly.
Some countries ban boiling of crustaceans alive, requiring that cooks kill the animal prior to boiling them. Apparently there’s a device you can get that will shock the head of a lobster, killing it instantly, or at least rendering it unconscious. Unfortunately, even if it’s anatomically feasible, the idea of using something like that on the hundreds of crawfish about to go into a pot isn’t very practical. There’s just too many packed too closely together. Some people advocate freezing first, but it’s not clear that’s a humane way to go either, and doing so with a large cache of crawfish is, again, not practical.
So even if people could be convinced that there was suffering to be concerned about here, I doubt there would be much change in the technique, although it might lead to less people wanting to eat them in the first place.
There is also the fact that lobsters only have 100,000 neurons, less than half what fruit flies and ants have, and only about a tenth of what bees or cockroaches have. I couldn’t find anywhere how many crawfish have, but I suspect it’s comparable to the lobsters. In other words, the resolution and depth of their experience of the world is extremely limited, far more so than many other animals whose welfare we typically disregard.
How much of a difference should that make? Is it right to think of them as conscious? Does the fact that they themselves have no empathy and couldn’t return ours, matter? How concerned about this should we be? Should we follow the example of the countries that outlaw boiling lobsters alive?