For centuries, crabs suffered in agony. Scientists have finally determined whether these creatures experience pain.

Crabs, lobsters, and other marine creatures are often caught to become human meals. They are frequently boiled alive before being eaten, as they are believed to not feel pain—crabs and lobsters lack the brain areas responsible for processing pain, according to Live Science.

However, a new study has changed everything. Researchers conducted a series of experiments to test the reaction of two dozen crabs to painful stimuli, such as being poked with a plastic tool or having small amounts of vinegar injected into their eyes, antennae, and the soft tissues between their claws and joints.

During the experiments, scientists also used electrodes to measure responses from the central nervous system. The results indicate that crabs exhibit nociceptive reactions, which were not observed when the researchers used non-painful substances like seawater. In simple terms, the scientists proved that crabs can indeed feel pain.

It is noteworthy that the experiments involved shore crabs (Carcinus maenas). The researchers found that these crabs possess nociceptors, nerve endings that detect bodily damage and send pain signals to the brain. Nociceptors have also been previously identified in humans and many mammals. They activate when the body is injured or at risk of injury, sending signals to the brain that alert it to potential threats.

According to co-author of the study, biologist Eleftherios Kassiouras from the University of Gothenburg in Sweden, the mere presence of nociceptors does not necessarily mean that an animal feels pain. It is known that these receptors can trigger a pain reflex—for example, the instinctive withdrawal of a hand from a hot stove. However, humans experience the sensation of pain in our brains. Therefore, while nociceptors alone do not prove that crabs feel pain, they are part of the larger puzzle.

Another study also indicated that lobsters and crabs respond behaviorally to pain. The combination of these behavioral reactions with the central nervous system responses increases the likelihood that the animal experiences pain.

In 2016, researchers conducted a study on hermit crabs and discovered that these animals exhibit protective behavior in response to injury: hermit crabs leave their shells to avoid electric shocks.

The new research on shore crabs meets another criterion, providing compelling evidence that crabs can feel pain. Considering all this evidence, scientists concluded that crabs and lobsters are indeed capable of feeling pain and have been suffering all along while being boiled alive in hot water.