Research on the facial expressions of animals, including cats, is still a very recent topic. The analysis of the facial expressions of animals began very recently. It turned out that, especially in the case of cats, it is very difficult to make any general observations, based on which it can be assumed that a specific expression in cats of all species tells us, for example, that kittens feel pain, fear or joy and pleasure. The matter is even more complicated by the fact that different species of cats have a different face structure, a different skull shape, the location of the nose, eyes and ears. Finding common features for all cat species has proven difficult, but not impossible.
Scientists decided to use machine learning in the study. It was also analyzed how when the kitten experiences emotions, the positions and movements of the muscles of its face change. Almost a thousand different feline grimaces were found. The next stage of the study was to look at the differences in the facial expressions of cats before and after surgery, then the grimaces related to the perception of pain were determined.
As a result of this research, the key features of a kitten’s facial expressions showing pain and suffering were discovered. These are:
- ears curled and spaced apart,
- frosty eyes or slight strabismus,
- lips tightened slightly in the nipple,
- cheeks pulled down towards the nose and eyes.