Cat owners tare familiar with their pets’ individual personalities, habits and preferences, and they can tell when the behavior is different than normal, but understanding what these changes mean can be much more difficult.

Veterinarians have identified 25 behavioral signs displayed by cats which could indicate that they are suffering pain, which could ultimately reduce suffering by leading to faster diagnosis of problems and illnesses. The researchers undertook the project as part of a larger initiative aimed at identifying the expression of pain in cats, focusing on the face. This initial study was a key prelude to the research to see if any facial elements were widely recognized as symptoms of pain. This was not found to be the case, however the scientists’ ongoing work indicates the face may actually be very useful in observing pain, although the signs are very subtle. 

The aim of the study was to collect and classify expert opinion on the possible behavioral signs in cats that denoted pain. These signs were classified as either 'sufficient' (their presence indicated that the cat is pain) or ‘necessary’ (the signs must be present to conclude that the cat is in pain) for pain assessment in cats.

By repeating a process of behavior analysis and selection, their work revealed 25 key 'sufficient' signs, such as an absence of grooming, hunched-up posture, avoiding bright areas, change in feeding behavior and difficulty to jump, which all infer pain, but no ‘necessary’ signs. These results highlight that being able to evaluate a set of behaviors will be much more reliable than looking out for one single symptom.

Professor Daniel Mills, Professor of Veterinary Behavioural Medicine at the University of Lincoln’s School of Life Sciences, said, “Both owners and veterinarians are clearly able to recognize many behavioral changes in cats which relate to pain. However, owners may not always recognize the clinical relevance of what they see. For example, they may view the changes as an inevitable part of natural aging and not report them to the vet as a concern, or at least not until the behaviors become quite severe. We hope that having an agreed list of more objective criteria, which relates to specific signs of pain, could improve the ability of both owners and vets to recognize it.

“Throughout the study, we consulted a variety of international experts so that we could be sure the signs were universal indicators of pain. By creating this core set of signs, we lay the foundation for future studies into the early detection of pain in cats, using scales which are crucially based on natural, non-invasive, observations.”

Citation: Isabella Merola and Daniel S Mills, "Behavioural signs of pain in cats: an expert consensus", PLOS One, DOI: 10.1371/journal.pone.0150040