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The Balance of Health

Claim

There is broad scientific agreement that mammals, birds and fish can experience pain, and growing evidence that some invertebrates such as decapod crustaceans can too.

The animals we farm can feel pain. For fish the evidence is strong; for crabs and lobsters it is now considered substantial.

Last reviewed
Reviewer
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Status
sample

Sample data. The figures and sources on this page are demonstration records showing how evidence will be presented. They are approximate and have not yet been through our review process. Read about how we will verify evidence.

Strong evidenceHow ratings work

Why this rating: Multiple independent reviews and expert bodies reach the same conclusion for vertebrates; invertebrate evidence is newer but substantial.

Supported by multiple systematic reviews or large, consistent studies using different methods, with few plausible alternative explanations.

300studies
Studies reviewed in the LSE sentience reportNot applicable, 2021. Source: Birch et al. (2021). Sample

Explanation

Sentience cannot be measured directly. Scientists use criteria such as nerve receptors for harmful stimuli, brain processing, responses to painkillers, and learning to avoid harm.

Mammals, birds and fish meet most of these criteria. A 2021 review of over 300 studies concluded that octopuses and crabs also show strong evidence of sentience.

Limitations
  • Subjective experience is inferred, not observed; how intense animals' experiences are remains debated.
Methodology
  • Criteria-based assessment of behavioural, physiological and neurological evidence.

Sources for this claim

Each source links to our record of what it found, its limitations and what we used it for, with a link to the original.

  1. 1
    Review of the evidence of sentience in cephalopod molluscs and decapod crustaceans

    Jonathan Birch, Charlotte Burn, Alexandra Schnell et al. (2021). Report commissioned by the UK Government (Defra).

    ReportSystematic ReviewStrong evidenceSampleView original ↗
  2. 2
    Defining and assessing animal pain

    Lynne Sneddon, Robert Elwood, Shelley Adamo et al. (2014). Animal Behaviour.

    Peer Reviewed StudyReviewModerate evidenceSampleView original ↗