stop your pork In an effort to make advances in animal welfare, European researchers have developed a tool to decipher the emotions pigs express in their various grunts. Across Switzerland, Denmark, Norway, France and the Czech Republic, biologists examined more than 7,000 recordings from 411 pigs, ranging from brief squeals of satisfaction at nursing to screams of desperation at slaughter, before classifying them into 19 different categories.
“We show that it is possible to determine the emotions of pigs from their vocalizations,” explains project leader Elodie Briefer, a lecturer at the University of Copenhagen. The study, published in the journal Nature in early March, offers a new way to improve animal welfare, according to the researcher, with a tool to categorize an emotion based on the noise produced.
“We also use a machine learning algorithm (…) that creates a spectrogram and trains itself to recognize negative and positive associations,” she specifies. Once this new way of monitoring is developed, it will allow farmers who only have tools for physical well-being to ensure the mental health of their animals. “If the proportion of negative noises increases, the farmer knows that something is probably wrong and can examine the pigs,” says the researcher.
For the Danish Agriculture Agency – the Scandinavian country is home to 13.2 million pigs, a European record of more than two pigs per capita – the implications of the study are promising. “This concept (…) could be a useful tool in the work to monitor the health and welfare of pigs, among other things,” said Trine Vig, a spokeswoman for the council. She says the study achieved 92% accuracy in determining whether the call was negative or positive and 82% accuracy in classifying the actual context in which the sounds were made.
According to the study, positive feelings are expressed in short tones, while negative thoughts are most often expressed in lengthy tones. But why deal with the pig rather than with the calf or the rabbit? For the authors of the study, the pig, known for its wide variety of squeaks and noises, was the perfect stallion. “They have a very powerful voice, which makes studying easy,” says the academic. They produce vocalizations all the time. Even in low-intensity situations, they continue to vocalize.