Cat owners the world over are familiar with their pets' individual personalities, habits and preferences, and are adept at spotting when their feline friends' behaviour differs from the norm. However, understanding what these changes mean can be a much more difficult task.

International veterinary scientists have therefore come together and identified 25 behavioural signs displayed by cats which could indicate that they are suffering pain.

The expert consensus, led by Dr Isabella Merola and Professor Daniel Mills from the University of Lincoln, UK, supported by cat charity Feline Friends (Derbyshire), represents the first list of its kind to be agreed by a panel of veterinary experts in feline medicine.

The research, published by scientific journal PLOS One, involved prominent academics and clinical practitioners from across the globe with specialisms including internal medicine, anaesthesiology, oncology, dentistry, behaviour, dermatology, ophthalmology and neurology.

The list they have created could now help cat owners and veterinary practitioners to spot important signs that the animals are in pain and ultimately reduce suffering by leading to faster diagnosis of problems and illnesses.

The aim of the study was to collect and classify expert opinion on the possible behavioural 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 behaviour 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 behaviour and difficulty to jump, which all infer pain, but no 'necessary' signs. These results highlight that being able to evaluate a set of behaviours 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 recognise many behavioural changes in cats which relate to pain. However, owners may not always recognise the clinical relevance of what they see. For example, they may view the changes as an inevitable part of natural ageing and not report them to the vet as a concern, or at least not until the behaviours 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 recognise 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."

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 recognised 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.

Caroline Fawcett, Chairman of Feline Friends, says that the results obtained from the research so far take a major leap towards a better understanding of our pets: "Cats are notorious for not showing that they are in pain, and the more that we can find out what the signals are, then the sooner we can get them to the vets for diagnosis and treatment. There is a long way still to go before the more subtle signs can be identified, but we are really excited about progress to date. The team at Lincoln is highlighting its dedication to cat welfare by tackling this extremely difficult project."