pigs emotions can now be decoded. Over tens of thousands of acoustic recordings collected throughout the lives of pigs, from their births to deaths, an international team of researchers is the first in the world to convert pig grunts into real feelings across a wide variety of situations and life stages.
The research is led by the University of Copenhagen, the ETH Zurich, and the National Research Institute for Agriculture, Food and Environment (NRAE), which is believed to be in the works in order to improve animal welfare in the future.
Is a pig grunt worth a thousand words? Perhaps so. A group of researchers from Denmark, Switzerland, France, Germany, Norway, and the Czech Republic have translated pig grunts into feeling. The results have been published today in scientific reports.
Researchers used over 7000 audio recordings of pigs to determine if an individual pig is experiencing a positive emotion (happy or excited) or a negative emotion from when he is born. The recordings were then collected in a wide variety of situations, both positive and negative, from the moment he was born.
"With this study, we demonstrate that animal sounds provide ample insight into their emotions. "We also demonstrate that an algorithm can be used to decode and understand the emotions of pigs, which is an important step toward improved animal welfare for livestock," says Associate Professor Elodie Briefer of the University of Copenhagen''s Department of Biology.
Short grunts are happy grunts
In both commercial and experimental scenarios, researchers recorded pig sounds, which based on the behavior of the pigs, are often associated with a positive and negative feeling. Positive situations included, among others, separation, fights between piglets, castration, and slaughter.
The researchers used different mock scenarios for the pigs to evoke more nuanced emotions in the midst of the spectrum. These included an arena with toys or food, and a corresponding arena without any stimuli. Along the way, the pigs'' calls, behavior, and heartrates were also monitored and recorded when possible.
In contrast, researchers examined more than 7000 audio recordings to see if there was a pattern in the sounds as a function of the emotions, and if they could discern positive situations and feelings from the negative ones.
The differences between the extremes were particularly interesting. Using an even more thorough evaluation of the sound files, the researchers discovered a new pattern that revealed what the pigs experienced in certain situations in even greater detail.
"When we look at positive and negative situations, we notice a clear difference in pig calls. There are far less amplitude, with minor fluctuations in amplitude. Grunts begin high and gradually decrease in frequency. By using an algorithm to discern these sounds, we can classify 92% of calls to the correct emotion." Elodie Briefer:
Farmers can monitor animal emotions
The study of animal emotions is a relatively new field that has developed over the last 20 years. Today, it is widely accepted that livestock''s mental health is crucial for their overall health. Despite, today''s animal welfare is focused primarily on livestock''s physical health. In fact, several systems can automatically monitor an animal''s physical health for a farmer.
"We have trained the algorithm to decode pig grunts. Now, we need someone who wants to develop the algorithm into a tool that farmers can use to improve the welfare of their animals," says Elodie Briefer.
She adds that, with enough data to guide the algorithm, the method might be also used to better understand the emotions of other mammals.