Pigs show strong evidence of compassion, at least by the measures scientists use to study it in animals. They catch each other’s emotions, respond to distress signals, and in controlled experiments, will actively free a trapped companion in about two minutes on average. While “compassion” is a complex human concept, pigs display many of the same building blocks: emotional contagion, prosocial helping, and social bonding.
Pigs Catch Each Other’s Feelings
One of the clearest signs of compassion in any species is emotional contagion, the ability to feel what another individual is feeling. Pigs do this reliably. When pigs watch a companion being physically restrained, they become visibly distressed themselves, freezing in place, attempting to escape, and producing sharp alarm calls that mirror the restrained pig’s behavior.
What makes this finding especially striking is that pigs don’t even need to witness the stressful event directly. In experiments where pigs had no view of their companion’s negative treatment but were reunited afterward, the observer pigs still picked up on the distress. They showed the same fear-related body language: ears pinned backward, alert posture, and heightened vigilance. Naive pigs with no prior experience of stress responded the same way after simply being near a companion who had been socially isolated. The emotional state transfers through proximity alone.
They Actively Help Trapped Companions
Emotional contagion on its own could be a reflexive response. What elevates pig behavior toward something closer to compassion is that they act on those feelings. In a 2023 study, researchers gave pigs the option to open a door that would release a trapped group member from a compartment. In 85% of cases, pigs freed their companion within 20 minutes, with a median time of just 2.2 minutes.
This wasn’t random exploration. Pigs were significantly more likely, and faster, to open a door leading to a trapped pig than to open an identical door leading to an empty compartment. The trapped pig’s distress signals mattered too: the more vocal the trapped pig was, the higher the probability that another pig would come help. This suggests pigs aren’t just bumping into doors by accident. They’re responding to a social signal and taking directed action.
Their Brains Are Wired for Social Processing
Pig brains share key structures with human brains that are involved in social and emotional processing. Brain imaging research has identified resting-state networks in pigs that are homologous to those in humans, including regions like the insular cortex, the anterior cingulate cortex, and the prefrontal cortex. In humans, the insular cortex plays a central role in empathy, helping us feel what others feel. The anterior cingulate cortex is involved in processing social pain. Finding these same networks active in pig brains doesn’t prove pigs experience empathy identically to humans, but it shows the neural hardware is there.
Stress Hormones Reveal Social Bonds
Hormonal data adds another layer. When pigs are separated from their social group, their cortisol (the primary stress hormone) surges to nearly three times baseline levels. Weaning and social isolation produce the highest spikes. After reunion with companions, cortisol drops significantly, though it stays somewhat elevated compared to baseline, suggesting the stress of separation lingers even after the group is back together.
Oxytocin, often called the bonding hormone, tells a subtler story. Salivary oxytocin in pigs drops to its lowest point during social isolation, the only context where pigs have no access to social support. During reunions, oxytocin tends to rise, particularly when reunited pigs engage in prolonged physical contact like nosing and nuzzling. This pattern mirrors what researchers see in other socially bonded species.
Pigs Communicate Emotion Through Their Voices
Pigs don’t just feel emotions internally. They broadcast them. Their grunts change in measurable ways depending on their emotional state. Grunts produced during negative experiences last significantly longer (averaging 0.43 seconds) than grunts during positive experiences (0.35 seconds). That difference, confirmed across hundreds of recorded vocalizations, means other pigs have acoustic information available to gauge a companion’s emotional state. Combined with the evidence that distress calls increase helping behavior, pig vocalizations appear to function as genuine emotional signals, not just noise.
Mirror Use and Self-Awareness
Compassion in its fullest sense requires some degree of self-awareness, the ability to distinguish your own experience from someone else’s. Pigs show suggestive evidence here too. In a landmark experiment, pigs learned to use mirrors to locate a hidden food bowl. After five hours of mirror exposure, seven out of eight pigs could see a food bowl reflected in a mirror, then walk away from the mirror and around a barrier to find the actual bowl in about 23 seconds. Naive pigs who hadn’t learned about mirrors looked behind the mirror instead.
This ability requires more than simple stimulus-response learning. Each pig had to observe its surroundings in the mirror, remember what it saw, relate the reflected image to real space, and then navigate accordingly. Researchers described this as “assessment awareness,” a cognitive capacity shared with primates, dolphins, elephants, and a small number of bird species. It places pigs in rare cognitive company and suggests they have the mental sophistication that more complex forms of empathy require.
Social Lives Built on Hierarchy and Affiliation
Compassion doesn’t emerge in a vacuum. It develops in species with complex social lives, and pigs fit that description. They live in groups with well-established dominance hierarchies, where individuals are classified as dominant, intermediate, or subordinate based on patterns of wins and losses in social encounters. Losing rank triggers measurable stress responses and changes in brain chemistry.
But pig social life isn’t all competition. Positive interactions, including sniffing, nosing, licking, and calm proximity, are common and form the basis of affiliative bonds. Pigs cooperate on foraging tasks regardless of whether their partner is a relative or an unrelated group member. In one cooperative task where pairs of pigs had to lift a log together to access food, kinship made no difference in success rates. Non-kin cooperated just as readily as siblings, suggesting that pig prosocial behavior extends beyond the family unit.
What “Compassion” Means in Pigs
Scientists are careful about projecting human emotions onto animals, and for good reason. Compassion in humans involves conscious awareness of another’s suffering, an emotional response to it, and a motivation to help. Whether pigs experience this full sequence subjectively is something no experiment can definitively prove. What the evidence does show is that pigs meet the behavioral and physiological criteria at every step: they detect others’ distress, become emotionally affected by it, and take action to alleviate it. They do this with brains that share the same empathy-related structures as ours, using vocal signals that encode emotional information, within social groups held together by affiliative bonds.
By any functional definition, pigs are among the most compassionate non-primate animals studied so far.