Invertebrates Shouldn't Be Treated Like They Don’t Feel Pain, Urges Review


Rachael Funnell

Social Editor and Staff Writer

clockMar 25 2022, 17:28 UTC
invertebrate pain

"Animal sentience is bound to complicate an already complex moral world." Image credit: Mana Photo /

Animal sentience has triggered parts of the world to rethink the way they treat (and farm) certain animals, including octopuses, crabs, and lobsters. Now, a review is urging that culturally and scientifically we embrace the same U-turn that saw babies being recognized as capable of feeling pain, this time for invertebrates.


Published in the journal Science, the paper explores the ethical and policy issues surrounding animal sentience and how the scientific community has come to acknowledge pain in closely related species.

Now, they are pushing for this understanding to be extended to distantly related species in the invertebrate walks of life in the face of increasingly building evidence of animal sentience among creatures like octopuses and crustaceans.

“When the medical community recognized infant pain in the 1980s, it was because the evidence was so overwhelming that physicians could no longer act as if infants are immune to pain,” write the authors. “A similar point is being reached where invertebrates can no longer be treated as if they only have a nociceptive response to harmful stimuli.”

A nociceptive response is when a living thing responds to painful stimuli without processing the feeling of pain. An example given in the paper is when a human will withdraw their hand from a hot surface before the understanding of pain has reached their brain.


Octopuses were found to be capable of feeling pain emotionally as well as physically in a 2021 study. In it, researchers gave octopuses a painful injection, which saw them avoid places associated with discomfort and attempt to soothe boo-boos by grooming.

While denying such pain response has to date, as the researchers put it, “been morally convenient during human’s history of animal exploitation” (in the US, octopuses aren't even considered "animals" in federal research), the growing body of evidence for pain experience in invertebrates surely calls for a rethink in our approach to these animals.

“Current research indicates that a wide range of animals have interests in avoiding felt pain, and that they would not consent to painful procedures if given the opportunity,” they wrote. “This makes pain a harm to them, and thus places a moral obligation on humans to recognize that harm and to avoid causing it if possible.”


As growing research and animal sentience legislation increasingly lean towards invertebrates as not being immune to feeling pain, the authors urge that these animals become a part of “our species’ moral landscape,” but it won't be easy.

“Although we are used to thinking about how our actions affect other humans, recognizing widespread animal sentience requires us to also notice – and consider – our impact on other species,” they wrote. “This way, animal sentience is bound to complicate an already complex moral world.”


  • animals,

  • ethics,

  • pain,

  • invertebrates