July 28, 2021 published at 1:57 AMReuters Dr. Liz Ruelle uses a new app called Tably that reads cat's faces and helps her monitor a cat's health at the Wild Rose Cat clinic in Calgary, Alberta, Canada, on July 14, 2021. Reuters Cat owners who love to take pictures of their furry friends now have a new excuse to pull out their smartphones and take a snapshot: it may actually help the cat. A Calgary, Alberta, animal health technology company, Sylvester.ai, has developed an app called Tably that uses the phone's camera to tell whether a feline is feeling pain. The app looks at ear and head position, eye-narrowing, muzzle tension, and how whiskers change, to detect distress. A 2019 study published in peer-reviewed journal Scientific Reports found that the so-called 'feline grimace scale,' or FGS, is a valid and reliable tool for acute pain assessment in cats.