“Listen to your pig”, it is the message of European researchers concerned with animal welfare who have developed a tool to decode the feelings of pigs through their growls.
Distributed between Switzerland, Denmark, Norway, France and the Czech Republic, a group of biologists have studied more than 7,000 recordings of 411 pigs, from the brief noises of satisfaction when eating to the desperate screeches in the slaughterhouse, and classified them into 19 different categories.
“We show that it is possible to determine the emotions of pigs based on their vocalizations,” The person in charge of the project, Elodie Briefer, from the University of Copenhagen, explains to AFP.
Their study, published in the journal Nature, offers a new way to improve animal welfare with a tool that allows us to classify emotions through the noise emitted, according to the researcher.
“We also use a machine learning algorithm (…) that produces a spectrogram and trains itself to recognize negative and positive contexts,” he adds.
Once developed, this new type of surveillance will allow farmers, who only have tools to understand physical well-being, to ensure the mental health of their livestock.
“If the percentage of negative sounds increases, then the breeder knows that something is probably wrong. and can go examine the pigs,” says the researcher.
For the Danish Agriculture Council, which with 13.2 million pigs holds the European record of more than 2 pigs per inhabitant, the implications of the study are promising.
“This concept (…) could potentially be a useful tool among others in the work of monitoring the health and welfare of pigs,” estimates its spokesperson Trine Vig.
“We reached an accuracy of 92% (…) in determining if the call is negative or positive, in the classification, and 82% in the classification of the real context in which the sounds have been produced,” says Brieffer.
According to the conclusions of the study, positive feelings are expressed by short sounds, while negative ones are externalized for a longer time.
Why focus on the pig instead of the calf or the rabbit? For the study authors, the pig, known for its varied growls, was the perfect pattern.
“They’re very vocal, which makes studying easier (…) They’re making noises all the time. Even in low-intensity situations, they continue to vocalize,” says the university student.