Vet-Approved by Dr. Luqman Javed

Crabs, along with other crustaceans, are often cooked by boiling them alive. When dropped into scalding water, crabs scramble and scrape the edges of the pot to escape. Is that a clear sign of pain and suffering, or merely an evolutionary response to aversive stimuli?

Whether crabs feel pain has been a hotly debated topic among scientists due to its many implications for the commercial crab fishing and restaurant industries. We’ll dig deeper into this topic below so you can know that you’re treating a crab as humanely as possible, whether it’s a pet or a main course.

The Evolution of Research into Animal Pain & Suffering

The idea that animals don’t feel pain was prevalent until recent decades. French philosopher René Descartes suggested that animals don’t feel pain because they lack sentience or self-awareness. This argument was accepted by most until the 1970s when bioethicist Peter Singer suggested that consciousness is not a consideration in pain. He argued that we don’t assume people with lower consciousness, such as infants or people with cognitive disabilities, experience less pain or experience pain differently.

Despite this argument, the notion that animals may not feel pain persisted into the 1990s. In fact, veterinarians in the U.S. were not taught to treat pain in animals prior to 1989 (the prevailing opinion then was to ignore pain). As the concern for animal welfare and pain relief grew, scientific studies were conducted to determine whether animals feel pain and, if so, how similar the perception is to that of humans.

In 2012, American philosopher Gary Varner reviewed the research on pain in animals and developed criteria for pain perception in animals. His conclusion was that all vertebrates experience pain, but invertebrates, such as crabs, likely do not.

man catching crab
Image Credit: Renato Laky, Pixabay

These criteria include:

  • A nervous system
  • Sensory receptors
  • Opioid receptors that demonstrate reduced responses to unpleasant stimuli with anesthesia or analgesic pain relief
  • Physiological changes to pain stimuli
  • Protective reactions, such as limping or self-mutilation
  • Avoidance learning
  • Balance of avoiding pain and satisfying other motivation, such as self-protection
  • Sentience

Research into Pain Perception in Crabs

Crabs are decapod crustaceans with an exoskeleton and a set of claws or pinchers. Some species are not true crabs, such as hermit crabs and king crabs, but share many similarities. Crabs do not have a neocortex, which is the foundation of the argument that they don’t feel pain.

Several studies were conducted to determine if crabs display one or more of the criteria for pain perception. At Queen’s University, researchers collected 40 European shore crabs and placed them into individual tanks. Half of the group was given 200-millisecond electrical shocks every 10 seconds for a duration of two minutes. The other half served as a control group.

In the shocked group, 16 of the crabs started walking in their tanks, and four attempted to climb out. The control group crabs walked into the tank, but none attempted to climb out. In addition to the behavioral responses, the shocked crabs showed significant physiological responses, including an increase in lactic acid, indicating stress.

Queen’s University also studied pain responses in hermit crabs. As a common species kept as pets, hermit crabs have soft exoskeletons and protect themselves by inhabiting empty seashells. When hermit crabs were given a shock, they left their shells and performed excessive grooming to the shocked area of their body.

hermit crab on sand
Image credit: Pixabay

The hermit crabs also chose between avoiding pain and self-preservation. As the shocks increase in intensity, hermit crabs are more likely to leave the protection of their coveted shells and seek out new shells. Conversely, if their environment is scented with the odor of a predator, the hermit crabs are more likely to stay in their shells following an electric shock.

Though this research is limited to two species, the results suggest that other crab species share the same pain perception and behaviors.

Do Crabs Deserve Animal Welfare Protection?

Based on current research, several animal welfare groups, including Advocates for Animals and PETA, argue that crabs can feel pain and, therefore, should be protected under the umbrella of animal welfare laws.

Humans eat crabs all over the world, and commercial fishermen use a variety of methods to catch and store their haul. Crabs often fight within crowded groups or experience amputation when pulled from nets. As they’re prepared for cooking, crabs are thrown into boiled water alive or may be electrocuted or chopped while still conscious.

man cooking crab
Image Credit: tiverylucky, Shutterstock

In 2005, the European Food Safety Authority released a statement attesting to the awareness, behavior, and complexity of crustaceans, recommending that they’re killed using only humane methods. Inhumane methods may include boiling crabs alive, storing marine crabs in freshwater, microwaving crabs, and removing the tissue or limbs while the crab is alive.

Commercial stun guns, such as CrustaStun, are available to electrocute shellfish and render them unconscious in 0.3 seconds and dead in 5 to 10 seconds. This is a more humane method than boiling, which can take minutes to kill.

aquarium plant divider

Final Thoughts

The fishing and storage methods, cooking methods, and research processes involving crabs and other crustaceans have raised questions of whether they feel pain, how they experience pain, and whether they deserve animal welfare protection. While research suggests that crabs do experience pain and suffering, some scientists and lawmakers disagree.

While we may never have a definitive answer, it may be best to err on the side of caution and treat the animal as ethically as possible, whether it’s your beloved pet you’re your soon-to-be dinner.

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Featured Image Credit: David Mark, Pixabay