Leading cat welfare and behaviour scientist Dr Lauren Finka delves into a fascinating study about how cats use their facial expressions to communicate.
They say a picture paints a thousand words, but when it comes to our notoriously enigmatic felines, is this really true? Just like their closest ancestors (the African or near-eastern wildcat), our domestic cats come fully equipped with some impressive biological functions that enable them to do much of their communicating ‘in absentia’.
Dr Finka plotted dots for the location of underlying facial muscles to measure expressions.
For example, cats possess special skin glands located over various parts of their bodies. These glands are able to secrete semiochemicals (chemicals that contain important messages) which they deposit within their environment when they scratch or rub against things, spray urine, and even when they deposit their faeces. These special chemical signals are left for other cats to find and decode, which they do using a specially adapted organ located in the roof of their mouths (known as the ‘Jacob’s organ’). As cats’ closest ancestors are mostly asocial, many of these chemical messages have been designed to help them steer clear of each other (unless mating might be on the cards of course!).
During the course of the cat’s domestication, we have vastly altered their physical appearance, creating the diverse range of modern cat breeds that we know and love today. What we haven’t done however, is intentionally try to breed cats in order to improve their social skills. The consequences of this are that while our pet cats might look a lot different from their ancestors, on the inside they might not be all that dissimilar. While our cats have been gifted these great signal-at-a-distance capabilities, they haven’t necessarily inherited the ability to communicate complex messages when in close proximity to others, for example via their behaviour and body language. And what if, rather than breeding cats to be better communicators, we’ve actually (unintentionally) done the opposite, by changing their looks in ways that make them even harder to ‘read’?
The science has already made it clear to us the potential downsides of indulging in our desires to create what we consider to be the perfect looking feline. Indeed, some cat breeds are much more likely to suffer from chronic health complaints, due to the specific genetic mutations they inherit, or simply because the physical proportions of their bodies make normal activities much more difficult for them to perform. For example, the cartilage abnormalities that give the Scottish Fold their characteristic ‘folded’ ears also cause them to suffer from painful joint problems and arthritis. Additionally, the very flat, disproportionate faces of brachychephalic cats, such as the Exotic Shorthair or modern Persian may cause issues with their eyes and breathing.
The facial expressions on cats can vary greatly.
Thanks to a recent study, we now also have some initial evidence to suggest that these breed related issues might not only affect cats’ physical health, but also their ability to express themselves and communicate via their faces.
Facial expressions are an important method of communication for many animal species. Such expressions can be used to signal individuals’ intentions or underlying emotions. Even in the case of the often stoic, domestic cat, research tells us that their facial expressions can indicate when they are in pain, fearful, frustrated, or comfortable. As owners, we will generally be aware of the different facial expressions our cats display. Some of us will also have a good idea about how our cats are feeling, or what they want, based on how their face looks at a given time.
However, research suggests that in general, when humans are presented with the faces of unfamiliar cats, we can really struggle to correctly identify if the cats in question are in a positive or negative emotional state. Interestingly, this research was limited to domestic short-haired cats, so this task might become even more difficult when people are presented with cats that have very different looking faces, such as the elongated face of the Oriental cat, or the flattened, condensed face of the Exotic Shorthair. Would we stand a chance at being able to tell if these cats were relaxed, in pain, or anxious from their facial expressions?
In this month’s article, we will focus on a study looking at how the facial features of cats have been altered due to intense selective breeding, and the impact this might have on their ability to clearly display different facial expressions and emotions.
The genetics of the Scottish Fold mean it has very different facial expressions to other cats.
What did the study do?
For this study, I focused on the faces of cats across nineteen different common cat breeds, including the Persian, Bengal, Norwegian Forest Cat, Egyptian Mau, Devon Rex, and Scottish Fold to name a few. I obtained approximately 100 pictures for each breed, only selecting an image if the cat appeared to have a ‘neutral’ facial expression. This was so that when I compared face shapes across the breeds, I could identify differences in their appearance caused by selective breeding, rather than differences caused by a particular emotional state they might have been expressing at the time the picture was taken.
I then began the painstaking task of measuring their faces. To do this, I manually placed 48 dots on each image, each dot corresponding to the location of underlying facial muscles. Using a special analytical technique called geometric morphometrics, I was then able to quantify how the locations of these facial points changed across the neutral faces of cats from the different breeds.
In theory, changes in the locations of these dots should indicate when the cat is displaying a particular facial expression, because we know how each of the muscles the dots are linked to contracts and changes the shape of the face during this process. However, because in this case, all the cats appeared to have ‘neutral’ expressions, if these dots showed significant differences in their locations across the different breeds, this tells us something quite important.
What this would mean is that when different breeds actually do display different facial expressions, it is unlikely that we would be able to clearly identify them, because there is simply too much variation in the general appearance of cats’ faces, even when no expressions are present. In other words, the expression on the cat’s face when experiencing fear or pain in one breed, might look the same as the expression on a cat’s face when they are relaxed or contented in another breed.
To test this hypothesis, I conducted a second study where I measured the degree to which the facial features of each cat breed corresponded to features we know are associated with the expression of pain in domestic shorthaired cats (for example, narrower ears positioned further apart, narrowed eyes, and the nose and mouth positioned closer together). I could then compare how much the faces of each breed appeared to show ‘pain like’ expressions, compared to faces of domestic short haired cats which were actually in pain (due to a routine neutering surgery).
How cats are bred can impact on how they live together in multi-cat households.
What were the main findings of the study?
As predicted, all of the facial points that I measured varied significantly based on the breed of the cat. This highlights how selective breeding has altered cat’s faces in ways that might make communication and expression more difficult for certain individuals.
Interestingly, the analyses also indicated that certain breeds had neutral faces containing ‘pain-like’ expressions, even though they weren’t actually in pain (as far as it was possible to ascertain). This was particularly true for breeds with rounded, flattened faces (also referred to as ‘brachycephalic’).
Why is this study useful?
This study raises the important issue of how our selective breeding of cats might not only impact negatively on their physical health, but also on their ability to communicate.
For example, if the faces of certain breeds such as the Scottish Fold look like they are permanently in pain, this might make it much more difficult for owners or vets to actually detect when pain is or isn’t present. In this case, it may be much more useful to focus on other aspects of the cat’s behaviour and posture other than their face.
However, not only has selective breeding changed the appearance of cats’ faces, but also the shape of their general bodies. It is therefore likely that differences in these features will also impact on cats’ abilities to communicate clearly. For example, take the classic ‘Halloween cat’ posture (legs fully extended, a highly arched back and large poofed-up tail) that cats display when they want to look as big and threatening as possible. This posture may be easier for a well-proportioned domestic shorthaired cat to display, compared to a munchkin cat with very short legs, or a tailless Manx cat.
However, much more research is needed to now try to understand how these general appearance differences across breeds might impact on cats’ abilities to clearly express themselves, as well as our, and other cats’ ability to understand them.
The ‘squashed’ face — in this case of a Persian — impacts on how cats communicate.
What does this mean for me and my cat?
Most of us will have a strong desire to understand our cat’s emotions and identify their needs as much as we are able. In multi-cat households, we will also want our cats to get along well with each other. What this research suggests is that we not only need to think carefully about the types of health conditions certain breeds might be more prone to, but also how their physical appearance might limit how easily they are able to communicate, both with us and with other cats.
This research suggests that we may have inadvertently selected certain breeds (such as those with brachycephalic faces) to look like they are physically compromised, even when they’re not. The reason we might find these sorts of facial appearances appealing is that they may look more vulnerable. This may then motivate us to want to care for and protect them, even when they don’t actually need it. The downside for our cats is that they may receive unwanted attention from us when they might just prefer to have some peace and quiet. Or equally, when they are actually in pain or distressed and do need our help, will we be able to tell? Such cats might also struggle more to communicate with each other, which could lead to less harmonious multi-cat homes. From a welfare perspective, avoiding purchasing cats that have been intensively bred, including those with more extreme, disproportionate features is recommended.
Facial expressions are one of the ways cats communicate.
Where did all the pictures of cats come from?
The photographs of the different cat breeds were from online sources such as Google. In this instance, looking at pictures of cats on the internet was my job for several months! I extracted the images of domestic shorthaired cats in pain from videos previously taken of a population of female cats during neutering at a veterinary clinic in Brazil. These cats were part of a previous study to support the development of a composite acute pain assessment scale, aimed to help veterinarians more accurately assess pain levels in cats and provide them with the right amount of pain relief. All cats received pre-surgery analgesia and then more pain relief post-surgery. The videos where cats were deemed to be ‘in pain’ were taken just before they received their second dose of analgesia.
Who conducted the study? When was it published?
The study was carried out by myself as part of my research at Nottingham Trent University (NTU). The study also included several co-authors from NTU, University of Lincoln and São Paulo State University in Brazil. The results were published in December 2020 in the open access journal ‘Frontiers in veterinary science’.