A recent study from the University of Gothenburg, published in the journal Biology, has made significant strides in understanding the sensory capabilities of shore crabs, suggesting these crustaceans experience pain.

Previous observational studies suggested that crustaceans might feel pain, but this research team is the first to use EEG-like measurements to directly assess their neural responses. Using sophisticated electrophysiological techniques, researchers examined how the crabs’ central nervous system reacted to potentially harmful mechanical and chemical stimuli. The study targeted sensitive parts of the crabs’ bodies, such as the soft tissues of their claws, antennae, and legs, applying mechanical pressure and acetic acid to these areas.

The findings revealed that the crabs responded distinctly to both types of stimuli, suggesting the presence of nociceptors—sensory receptors that detect damage and potentially harmful conditions—indicating a sophisticated sensory system that could support the capability for pain perception.

“We could see that the crab has some kind of pain receptors in its soft tissues, because we recorded an increase in brain activity when we applied a potentially painful chemical, a form of vinegar, to the crab’s soft tissues. The same happened when we applied external pressure to several of the crab’s body parts,” explains biologist Eleftherios Kasiouras from the University of Gothenburg, who led the study.

Mechanical stimuli prompted quick, intense responses from the crabs, while chemical stimuli induced prolonged reactions, showcasing how these animals process different types of environmental threats.

“It is a given that all animals need some kind of pain system to cope by avoiding danger. I don’t think we need to test all species of crustaceans, as they have a similar structure and therefore similar nervous systems,” says Eleftherios Kasiouras. (Totally Vegan Buzz does not condone the use of animals in research.)

Past research has also provided compelling evidence supporting the idea that these animals are capable of experiencing pain.

In 2013, a landmark study demonstrated that crabs avoided areas where they had previously been subjected to electric shocks. This behavior strongly suggested not only an awareness of pain but also the ability to remember and act on past painful experiences, implying cognitive processing beyond simple reflexes. Similarly, other experiments have shown that lobsters and prawns exhibit stress-like physiological responses when exposed to harmful conditions, such as boiling water or extreme handling.

Further research into hermit crabs highlighted their ability to make trade-offs between the prospect of pain and potential rewards. For instance, hermit crabs would leave their shells when exposed to painful stimuli, even when doing so exposed them to greater risks of predation. This kind of decision-making indicates a complex processing of pain signals, a trait previously thought to be limited to higher vertebrates.

Every year, an estimated 580 billion farmed crustaceans, including crabs, lobsters, prawns, shrimp, and crayfish, are killed to meet global demand for seafood. This staggering number highlights the scale of the industry and the vast number of sentient beings affected. Crustaceans are used in various culinary practices worldwide, ranging from boiling and steaming to frying and grilling, often with little consideration for their welfare.

With emerging research confirming that these animals can feel pain, the treatment of crustaceans in farming and food preparation is coming under scrutiny. Unlike terrestrial livestock, crustaceans are largely excluded from animal welfare laws in most countries, leaving them vulnerable to practices that may cause significant suffering.

In 2021, the UK officially recognized animal sentience in law, including crustaceans and cephalopods, acknowledging that they can experience feelings. However, methods such as boiling crabs and lobsters alive or de-shelling prawns while they are still alive remain widespread throughout the farming industry.

While this study suggests finding a humane way to kill these animals, many animal advocates argue that no method of farming or killing can ever truly be humane. The only ethical approach is to abstain from eating crustaceans—and all animals—altogether, advocating for a lifestyle that eliminates their suffering entirely.