At any given time, as many as 12,500 Duroc pigs are sniffing the farmyards of Imani Farms, a pig farm in southwestern Ontario.
The ranch’s lofts are a cacophony of screeches, screams, barks and growls, each sound conveying a different feeling or need. Pigs are expressive animals with a wide variety of vocalizations, according to Stewart Skinner, 38, a co-owner of the farm. Interpreting their conversations can occasionally make even experienced farmers stupid.
“I’ve often joked that this job would be much easier if we could speak pig,” Mr Skinner said.
Deciphering the emotions behind that squeak might soon get a little easier. Researchers in Europe have developed an algorithm that assesses the emotional state of pigs based on the sound the animals make.
“It is now widely accepted that animal welfare is based not only on the physical health of animals, but also on their mental health,” said Elodie Briefer, an associate professor of biology at the University of Copenhagen and author of the study published this week in the journal. Scientific Reports. The sooner a farmer can discern whether an animal is happy or sad, the sooner any problems in the animal’s environment that could affect the animal’s health can be addressed.
Pigs are among the more articulate pets and are more likely to produce a wider range of sounds than relatively taciturn goats, sheep and cows. To crack the code of pig communication, scientists in five research labs across Europe used handheld microphones to collect about 7,400 different calls from 411 individual pigs. The calls are recorded during all kinds of situations in a pig’s lifespan, from birth to slaughterhouse.
Researchers then assigned each sound a positive or negative emotional value based on what the article calls “intuitive inference.” In other words, researchers made an educated guess as to how the pig likely felt about the event in which the sound was recorded (i.e., eat, good; castration, bad).
On the first listen, most people tend to do a little better than chance to guess a pig’s feelings based on the sound alone. However, listen carefully to enough pig calls and patterns will form.
Grunts associated with positive emotions — the sounds pigs make when feeding, running, or reuniting with their mothers or littermates after a separation — tend to be shorter and have a monotonous consistency in tone.
Unsurprisingly, an unhappy pig sounds awful. Situations that triggered screams of fear included being accidentally crushed by a mother sow (a common danger to piglets), awaiting slaughter, starvation, fighting and the unwelcome surprise of strange people or objects in their pens. The screams, screeches, and barks recorded from animals experiencing fear or pain are both longer in duration and more variable in tone than the sounds of contentment.
When people are taught to listen to these simple differences, people can more accurately interpret an animal’s emotional state, said Dr. letter. But artificial intelligence performed best of all. The researchers’ algorithm, designed by co-author Ciara Sypherd, correctly identified the animal’s emotion as positive or negative 92 percent of the time.
The research is the product of SoundWel, a European Union sponsored project to improve animal health and welfare. Researchers with the project are now looking to partner with an engineer who can incorporate their data into an app or other tool that farmers can use to interpret their animals’ calls and emotional state in real time, said Dr. letter.
Understanding the emotions of animals has practical and legal ramifications. Animal laws such as those currently in the UK Parliament state that animals can think and feel, and that the government must consider their well-being when making policies that could affect them. The European Union recognized animal awareness in 2009.
A cost-effective and easy-to-use pig grunt decoding tool can be a valuable asset to a farm, Mr Skinner said.
“The ability to spot problems early is the single biggest determinant of treatment success,” said Mr. Skinner. “Any tool that can be adapted to barn settings and that would increase the understanding of what the individual animals are feeling would be valuable.”
