Are grumpy cats really so grumpy? Study suggests selective breeding may have impacted cats’ ability to clearly express themselves

Breeding cats to have certain features could be hindering their ability to communicate how they are actually feeling

The research – by cat behaviour and welfare specialists at Nottingham Trent University – argues that over time people have selectively bred cats based on human preferences and to display specific features that we find appealing, but which might make it more difficult for individuals to communicate effectively.

Breeding cats to have these features – such as brachycephalic breeds with flat faces, big eyes and foreheads and often seemingly grumpy expressions – could be affecting their ability to communicate how they are actually feeling.

The study involved the use of an analytical technique called geometric morphometrics, which enables the researchers to plot points on images of cats’ faces to correspond with their underlying facial muscles.

Changes in the location of these muscles are associated with changes in facial expressions displayed by cats, therefore the method can be used to identify how these plots move depending on an individual’s internal state, such as when they experience pain.

The faces of 19 popular breeds – including Persian, Bengal, Norwegian Forest, Egyptian Mau, Devon Rex and Scottish fold – with about 100 images across each breed, were used as part of the research.

Images of cats with ‘neutral’ facial expressions were chosen so that the researchers were able to distinguish changes caused by selective breeding specifically, rather than differences caused by specific expressions and underlying emotional states the cats may have been experiencing at the time.

The team placed 48 dots on the image of each cat’s face, enabling them to see how these points changed across all breeds.

While the different breeds of cats all had neutral expressions – and therefore the facial muscles technically should remain consistent – the researchers identified significant variations in how the dots were distributed, illustrating how selective breeding over time has altered cats’ faces.

What this might mean is that the neutral facial expression in one breed might now look the same as the expression of pain or discomfort in another.

To test this, they looked at how facial features of each breed corresponded with features known to be associated with the expression of pain in domestic shorthaired cats – narrower ears positioned further apart, narrowed eyes and the nose and mouth positioned closer together.

The researchers found that, while the system could differentiate between pain and no pain in domestic shorthaired cats, these differences were no longer detectable when analysed across wider, more diverse populations.

Brachycephalic cats – those with flat faces which have gone through some of the most extreme selection to have a certain appearance – had greater pain-like expressions compared to breeds with more proportioned features (mesocephalic) and those with elongated faces (dolichocephalic).

And they found that for particular flat-faced breeds, their neutral (not in pain) faces produced scores indicative of greater pain than most other breeds, including those actually in pain.

It is already known that some cat breeds are more likely to suffer physical health problems as a result of how they have been bred. For example, brachycephalic cats such as the exotic short hair or modern Persian can have issues with their eyes and breathing.

The faces of 19 popular breeds were used as part of the research