It is a common misconception that crabs and lobsters scream when you dip them in boiling water to cook.
But even if this myth isn’t true, scientists say there are still good reasons to avoid this classic kitchen technique.
Zoologists from the University of Gothenburg are calling for an immediate ban on cooking crabs alive after making a groundbreaking discovery.
The researchers have proven that crabs can actually feel pain, just like any other animal, meaning that being boiled will likely be an excruciatingly painful death.
Lead author Eleftherios Kasiouras, a PhD candidate at the University of Gothenburg, told MailOnline: ‘We believe that boiling shellfish alive should be banned and that other techniques such as electrostunning should be applied at the time of catching the shellfish.
‘More and more evidence is emerging, including our research, that decapods (crabs) experience pain, so we should treat them as we would other animals.’
In their study, the researchers used brain scans to see how crabs’ nervous systems respond when exposed to painful stimuli.
This revealed the first evidence that crabs process pain in exactly the same way as humans.
Researchers call for an urgent ban on cooking crabs alive as a shocking study proves they can actually feel pain (stock image)
The researchers took partially paralyzed shore crabs, also known as European green crabs, and attached electrodes to clusters of nerves called ganglia, which are part of their central nervous system.
The crabs were then subjected to painful chemical or physical stimulation using solutions of acetic acid and specialized probes.
They found that damage or stress to the claws, antennae and legs caused a spike of electrical activity in the associated ganglia.
Mr Kasiouras says: ‘Our findings showed that when a painful stimulus was applied to the tissues of shore crabs, that stimulus was transmitted to the brain. These reactions were prolonged and intense.”
The researchers also tested the same areas with non-painful stimuli such as salt water, but did not see the same kind of response.
‘We didn’t get any reactions, so what we saw was certainly not a reflex. From our findings we saw that these were responses to pain,” says Mr Kasiouras.
Previous research has shown that crustaceans such as crabs, shrimp and lobsters are likely to experience pain.
However, these studies focused on observational methods and looked at evidence such as touching the affected area more often or trying to avoid the danger.
Researchers recorded the brain activity of paralyzed crabs while they were subjected to painful stimulation by acid and physical probes. They discovered that these tissues contained pain receptors that sent messages to the brain when stimulated
This graph shows the spike in brain activity that occurs when acetic acid is applied to the leg of a shore crab. The red vertical line indicates the moment the acid was applied
What makes this recent study different is that it is the first to document how a crustacean’s nervous system actually responds to noxious stimuli.
In our bodies, and in the bodies of many other animals, specialized receptors called nociceptors detect damage and send signals to the central nervous system that are interpreted as pain.
In their paper, published in the journal Biology, the researchers argue that the existence of nociceptors is a “key criterion” for an animal to feel pain.
The neural activation observed by the researcher is a strong indication that there must be pain receptors in the tissue that send responses to the central nervous system.
And what applies to crabs almost certainly applies to other crustaceans with a similar structure and nervous system.
This is therefore strong evidence that crabs, shrimp, crayfish and lobsters are all capable of feeling and processing pain.
In light of these findings, the researchers say there is an urgent need for more legal protections for crab welfare.
Co-author Dr Lynne Sneddon, an animal pain expert at the University of Gothenburg, said: ‘We need to find less painful ways to kill shellfish if we want to continue eating them.
Although they are not currently covered by EU animal welfare legislation, the researchers say their research shows that crustaceans, including crabs such as the European green crab used in the toad (pictured), lobsters, shrimps and crayfish, all feel pain when they are killed.
The researchers are calling for crabs to be stunned with electricity when captured so they don’t suffer a painful death from cooking or suffocation (file photo)
‘Because we now have scientific evidence that they both experience and respond to pain.’
In the EU, crustaceans are one of the few animals not covered by welfare laws. This means that there are no guidelines on how to handle it in the laboratory or in the kitchen.
That means it is legal to cut or cook crabs while they are still alive, which is not the case for the mammals we eat.
While the researchers acknowledge that their own research was undoubtedly painful, they emphasize that as few crabs as possible were used in the hope of improving the welfare of all crustaceans in the future.
Mr Kasiouras added: ‘In the UK, decapod crustaceans are considered sentient, so animal welfare legislation should certainly be extended to these groups of animals.
“More research is needed on that topic and we hope we can announce some guidelines in the future.”