Evidence-based profiles of animal cognition, emotions, and sentience. Each entry is backed by scientific research on animal behavior and neuroscience.
Sentience is the capacity to have subjective experiences and feelings. This includes the ability to feel pain, pleasure, and emotions. The sentience scores shown are based on the best available scientific evidence regarding each species' neurological capacity, behavioral indicators, and cognitive abilities.
Growing scientific evidence suggests that at least some invertebrates, particularly cephalopods (octopuses, squid, cuttlefish) and decapod crustaceans (crabs, lobsters, crayfish), are likely sentient. The UK became the first country to formally recognize these animals as sentient in law through the Animal Welfare (Sentience) Act 2022.
Many jurisdictions and scientific reviews increasingly recognize strong evidence for sentience in cephalopods and decapod crustaceans (e.g., learning, flexible behavior, responses consistent with pain). This has driven policy recognition in some places.
Yes. The scientific consensus, formalized in the Cambridge Declaration on Consciousness (2012) and reinforced by the New York Declaration on Animal Consciousness (2024), is that mammals, birds, and many other animals possess the neurological substrates necessary for conscious experience, including the capacity to feel pain.
Fish pain is one of the most actively debated topics in animal welfare science. Strong evidence supports pain capacity: Sneddon (2003) identified nociceptors in fish responding to mechanical, thermal, and chemical stimuli, and fish show prolonged behavioral changes after painful stimuli that go beyond simple reflexes. However, prominent skeptics including Rose (2002) and Key (2016) argue that fish lack the neocortical structures required for conscious pain experience. The 2024 New York Declaration on Animal Consciousness — signed by over 500 scientists — concluded there is "at least a realistic possibility" of conscious experience in all vertebrates, including fish. The weight of evidence tilts toward fish having at least some capacity for suffering, but genuine scientific disagreement remains about whether their experience is comparable to mammalian pain.
No. While plants exhibit sophisticated responses to damage and environmental stress, these are biochemical and hormonal processes, not conscious experiences. Plants lack neurons, synapses, nociceptors, and a brain — the fundamental biological structures required for pain perception. The scientific consensus is that plants are not sentient.
Fish pain is one of the most actively debated topics in animal welfare science. Sneddon (2003) identified nociceptors in rainbow trout, and fish show prolonged behavioral changes after painful stimuli. However, Rose (2002) and Key (2016) argue fish lack neocortical structures for conscious pain. The 2024 New York Declaration on Animal Consciousness (500+ signatories) concluded there is "at least a realistic possibility" of conscious experience in all vertebrates, including fish. The weight of evidence tilts toward fish having pain capacity, but genuine scientific disagreement remains.
Evidence for insect sentience is growing but remains less certain than for vertebrates; a precautionary approach is reasonable. Veganism typically reduces direct harm to large, clearly sentient animals and reduces land use—likely reducing many forms of animal suffering overall, including incidental insect deaths.
The scientific mainstream accepts that mammals and birds have the neurological and behavioral capacity for pain and other affective experiences. This is reflected in broad scientific consensus statements and welfare science.
Sus scrofa domesticus
Pigs demonstrate cognitive abilities in specific domains--such as spatial memory, object discrimination, and social learning--that are sometimes compared to those of young children or dogs. However, cross-species cognitive comparisons are inherently limited, as different species excel in different domains (Marino & Colvin, 2015).