Pain is as plain as the look on its face

Many pet owners believe they know how their dog or cat is feeling.

They may be right. Research into facial expressions of emotion and pain could help producers and veterinarians better understand when an animal is feeling discomfort.

People who spend a lot of time around animals may already have an ability to read emotions but now there is scientific evidence and possibly a computer application to understand variations in facial expressions, said Mirjam Guesgan.

She has researched facial expressions in sheep and lambs when she completed her doctorate at Massey University in New Zealand.

“By doing this kind of research, we are bringing those sorts of things to people’s attention. Once they are aware of it and you can train people to look for these different expressions then they can do it themselves,” she said.

She recently completed a post-doctoral fellowship at the University of Alberta.

Mammals display a spectrum of emotions and when people have more empathy for them they can offer better treatments or protect themselves when working around large or dangerous animals.

“If you are not reading the horse’s body language or face correctly, you can get injured,” she said in an interview.

To prepare a computer model, good base line data is necessary to determine meaning in facial expressions.

“It involves decoding the facial features and showing how they change when an animal shows a particular kind of emotion.”

Despite their different anatomy, mice, rats, rabbits, horses and sheep all display similar faces to indicate pain, which can be transferred to a pain coding indicator called a grimace scale. When in pain, many animals squint their eyes, hold their ears back and tighten their mouths. They may puff out or suck in their cheeks.

“You need to identify those features first and then you can program them into some sort of computer algorithm,” Guesgan said.

That algorithm compares the image of the animal when it is has a neutral expression to the face that indicates pain.

Most of her work has been done with sheep. They often hide their pain but during the course of the research their facial expressions did change. This may be a way to communicate with one another.

“You might want to let others in your group know, ‘hey I am in pain, help me out or go away,’ ” she said.

Research was done on the lambs after their tails were docked. They were not subjected to any extra circumstances to elicit a response.

Happiness or contentment is less researched, although people often have a good sense of how an animal such as the family dog is feeling.

“When it comes to animal welfare research on the positive side, there hasn’t been that much work done. It is an emerging field.”

Studying positive emotions in dogs may be a good start.

“They co-evolved with us. They have evolved over about 100,000 years together so the cues that we are sending back and forth especially could be real,” she said.

Studying facial features is easier than interventions like monitoring heart rates or blood tests looking for stress hormones.

At the same time, people can’t jump to conclusions.

“We have to be a bit careful be-cause it is very tempting to want to put a particular emotion on an animal based on facial features.”

“We may think an animal is experiencing something but we need scientific evidence to really tell those facial expression or heart rate or changes in brain activity. Any of those can give use clues as to how an animal is feeling,” she said.

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