They may appear aloof and peaceful but a new scientific study says cats might be suffering in silence. The study by Dr. Daniel Pang from the University of Calgary Faculty of Veterinary Medicine and a colleague from the University of Montreal, says cats are notoriously hard to diagnose when it comes to their pain levels. But they have created a scale that looks at the feline facial expression, including ears, eyes and even their whiskers. A closing or narrowing of the eyes or a flattening of the ears can be a sign that the animal is in pain. Pang said veterinarians have historically under prescribed pain medication to cats as opposed to dogs. The study, by Pang and Dr. Paulo Steagall at the University of Montreal, was published last month in 'Scientific Reports'.