Altruism: behaviour of an animal that benefits another at its own expense. OR: selfless concern for the well-being of others. In other words, altruism is helping others without necessarily looking for a reward in return. It is an act of giving.
However, an interesting aspect of altruism is that it normally concerns one sentient being helping another sentient being – usually humans helping humans – but the benefit if felt by the group so there is a distant reward in terms of group survival.
For humans it is said that “Altruism and selfishness are 30–50% heritable in man in both Western and non-Western populations.” I take that to mean that up one half of humans inherit the gene that makes them able to behave altruistically.
For pigs it is 85%! That’s according to an interesting study published in the Proceedings of the Royal Society B journal.
The Times reports on this study, concerning 75 German landrace pigs split into eight groups. Each of the eight groups lived in a pen with doors that led to 2 smaller test pens. The doors had handles which the pigs could turn with their snouts.
The scientists took one pig and kept them entirely separate from the others in the group. This caused the pig to feel moderately stressed because pigs are highly social animals. The pig was then put into a closed test pen.
This was done 74 times in isolating different pigs. In 85% of cases, within 20 minutes, the trapped pig was released by a helper pig. The average time before release was a little more than two minutes. In other words, there was a rapid response by pigs to help the trapped pig.
For a ‘control’, they noticed that helper pigs did not open the door leading to the second test pen which was empty. This confirmed that the helper pigs were not simply exploring empty pens but deliberately releasing a pig who was confined to an adjacent pen and who they felt had to be released.
I take this to be an altruistic form of behaviour by pigs in a group to save a pig that had been removed from the group and confined elsewhere.
The Times author explains it thus: “A study looked at whether pigs would rescue a peer that had been taken from its group and put in a pen by itself. They could free the lone pig by using a door handle with their snouts. They almost always did, usually releasing the separated pig within minutes.”
The scientists reason that the pigs that were free were much more likely to open the compartment containing the trapped pig than if there was no pig in the compartment. This wasn’t about curiosity this was about saving a pig from their captivity.
They also found that those pigs that had spent time looking through a window between the test pen and the home pen were more likely to rescue the trapped pig.
The conclusion is that, “our study shows that pigs appear to be motivated to help others without receiving any direct benefits, which is likely to occur in many highly social species but has been difficult to prove experimentally.”
To me, it looks like pigs are more altruistic than humans! That wouldn’t surprise me if it’s true. It also confirms how intelligent pigs are. It also confirms to me how cruel farmers are to pigs when they are subjected to intensive farming and associated cruel practices.
Note: study referred to: Sibly, R., Curnow, R. Selfishness and altruism can coexist when help is subject to diminishing returns. Heredity 107, 167–173 (2011). https://doi.org/10.1038/hdy.2011.2