When a fight becomes particularly thorny and drawn out, sometimes it takes the involvement of an empathetic, calming third party to lower the temperature in the room.
According to a study published Tuesday, the hoofed mammals appear to have the cognitive ability to watch and empathize when two other pigs fight — and then intervene afterward to reduce the levels of aggression or anxiety — a form of social regulation that can benefit the wider group.
The study observed that bystander pigs sometimes intervene after a conflict by approaching one of the warring parties and initiating physical contact, by applying the calming touch of their snouts, rubbing either of the parties with their ears or simply sitting up against one of the opponents. Occasionally, a pig also placed its entire head over the body one of the combatants, which was also effective.
“Pigs are highly social, and they have a very complex and high cognitive capacity to recognize familiar individuals,” Giada Cordoni, one of the study’s authors at the University of Turin, told The Washington Post.
When a victim is contacted after a fight, its anxiety levels drop, while aggressors that are approached are less likely to attack the victim — or other members of the group — again.
Cordoni describes this resolution strategy involving a third pig as a “triadic conflict mechanism.” The study marks the first time it has been observed in the species — having previously been identified only in humans, wolves, primates and birds. It also illustrates what she describes as pigs’ “evolutionary convergence with humans.”
Louisa Weinstein, a conflict mediation specialist who works with humans, agrees.
“When a third person comes in, it’s an opportunity for someone to hear you. In a conflict, the other person isn’t understanding your perspective. The third party is going to at least understand your perspective,” she said in a telephone interview. “The third party contains the conflict and the emotions associated with it. … We automatically regulate and behave better when someone else is there.”
The Italian researchers spent six months in 2018 observing 104 pigs on a farm near Turin, in northern Italy. The pigs were free to forage throughout a 13-hectare woodland area — an environment that let them move and behave naturally. Researchers collected hours of video data to analyze.
They found that domestic pigs can take part in a wide array of post-conflict strategies in the minutes after a fight.
The two fighting pigs can engage in reconciliation — or a third pig not involved in the conflict can make unsolicited physical contact with the aggressor or the victim, often with its snout.
“The nose is very important for pigs, not just for communication and exploration, but for social interaction,” Cordoni said.
Cordoni added that a victim’s anxiety levels were seen to decrease after such contact, whereas “when the third party contacted the aggressor, we can detect a reduction in the frequency of the aggression directed at the other victim.”
This suggests that bystander pigs have the cognitive and empathetic skills to detect emotions like anxiety in other pigs. The physical contact — which is not solicited by either of the antagonistic animals — also suggests that the third pig knows when the moment is right to intervene, as well as how to do it, the researches said.
Another observation made by the scientists, suggesting a further similarity pigs share with humans, was the influence of family dynamics on how fights played out. Bystander pigs were more likely to intervene with pigs they were closely related to, suggesting they recognized and responded to family ties.
Conversely — in intrafamily fights, pigs that were distant relatives were more likely to engage in reconciliation compared to pigs that were closely related. Cordoni suggests this might be because closely related pigs are more secure in their relationships, meaning that any damage caused by conflict tends to be lower, whereas unrelated pigs have weaker preexisting ties, making conciliatory behavior necessary.