Saturday January 20, 2018

Do lobsters feel pain when we boil them alive?

Boiling live lobsters is the most popular way to cook them.

Boiling live lobsters is the most popular way to cook them.

Listen 9:42

The government of Switzerland has passed a law stating that as of March 1st, people there will no longer be able to put a live lobster into a pot of boiling water to cook it without stunning it first. Boiling live lobsters is the most popular way to cook them. We justify it with the thought that lobsters can't feel pain like we do, but is that right? Can lobsters feel pain?

Dr. Robert Elwood, a professor emeritus of animal behaviour at Queen's University Belfast, has spent the latter part of his career trying to figure out if there is such a thing as pain for lobsters. He says there's been quite a bit of research in this area in the past 10 to 15 years and the evidence is stacking up. "We can't prove pain in any animal species. You can only do studies and if they're consistent with the idea of pain, you begin to think perhaps we should give them the benefit of the doubt. It's what we call the precautionary principle and [it] gives them some protection in case they do feel pain."

Probing for signs of pain

You can't ask a lobster if it feels pain. There's plenty of anecdotal evidence out there of lobsters that try to move away from heat, but it's extremely difficult to know if that's because of a reflex or if they truly are feeling the heat as pain.

"Pain is not something we perceive," says Elwood. "It's an interpretation of a nervous input."

He first wanted to determine if crustaceans like lobster were acting by reflex. The first experiment he did was to put acid onto a prawn's antenna to see what it would do. Prawns, like other decapod crustaceans such as crabs and lobsters, all have similar nervous systems.

"What I found was that the prawn would groom that specific antenna, not the alternative one. And that could be reduced if we applied to a local anesthetic. But they showed an awareness of the site of the acid and what they were doing was not consistent with the idea of a reflex."

The lengths crustaceans will go to avoid a 'painful' stimulus

Another way scientists can try to tease apart whether a lobster is feeling pain is to look at motivational tradeoffs — what a crustacean will give up to avoid a noxious stimulus.

Elwood says, "A reflex will occur regardless of your motivation to do other things. If you tap someone's knee and ankles on the foot to move by reflex, it'll move the same way if they're hungry or not. It doesn't matter."

His team ran a number of experiments where they gave shocks to hermit crabs, the crabs that inhabit empty gastropod shells.

"Now some crabs got out of the shell, but they were more likely to get out of an un-preferred type of shell than if they preferred that type of shell. They were trading off between keeping the good quality shell and avoiding the shock," says Elwood. "The remarkable thing there is that they're giving up an extremely valuable resource in order to escape the noxious stimulus, the electric shock."

He says this is another bit of evidence that's "consistent with the idea of pain" because humans, if they can, will also pay a lot of money to avoid pain.

Different nervous systems

One of the reasons it is so challenging to figure out definitively if crustaceans like lobsters experience pain like we do is because their nervous system is very different from those of vertebrates like us. Some scientists believe that since lobsters don't have the same brain anatomy as we do, that they cannot feel pain.

Elwood thinks there's a good chance that different animals, even with very different nervous systems, can perform the same functions. He gives the example of how lobster, octopus, and humans see.

"They all have parts of the brain devoted to analysis of visual stimuli, but they have independently evolved. They are completely different, but nevertheless they perform the same function. So it's quite possible, given the utility of pain in promoting the fitness of animals, you could have the same function in completely different organisms."

Weighing the evidence

"What we have is a list of criteria that you would expect to see of pain much beyond this is simple withdrawing or away from the subject," says Elwood. "When you find that the animals fulfil those criteria, you are beginning to suspect that perhaps they might feel pain."

But not everyone agrees.

Greg Irvine, the executive director of the Lobster Council of Canada, says, "This is an issue that's come up several times over the last few years. And we take it very seriously in the lobster industry. We ensure that the lobster is well looked after from the catching through the shipping and holding and into storage and into use for consumers and restaurants. And we encourage people to properly look after them. The jury is still out. There's no real scientific consensus on whether they feel pain if they're boiled, but it's the most traditional way to do it."  

Lobster cut

Dr. Zen Faulkes, a scientist who studies crustaceans, created this diagram to demonstrate what he says is the quickest way to kill a lobster at home. (Zen Faulkes/University of Texas Rio Grande Valley)