Humans caused cats to evolve. That’s not a particularly dramatic statement. After all, they’re domesticated animals. Their very existence is the result of artificial selection by us. However, research on our feline friends has identified ways in which we may be unintentionally shaping the evolution of their species.
The research in question is a follow-up to earlier work on dogs, conducted way back in 2013. Because mans’ best friend should get research priority, naturally.
This earlier research found that dogs evolved to be cute. Dogs which retain puppy-like characteristics into adulthood are preferred by people. In particular, dogs which raise their inner eyebrows in a cute, puppy-like way are more likely to be adopted out of shelters.
Based on this, the researchers inferred that dogs have been evolving to become more appealing to us. The species was undergoing hefty artificial selection as we picked out features we wanted. But that didn’t stop natural selection. Suddenly it became advantageous for a dog to look cute to us. And the inner eyebrow raise was born, selected for, and continues to influence how we feel about dogs today.
Four years later the same group of researchers are back, asking the same questions but of cats. Have we been unintentionally influencing their evolution? Accidentally selecting for characteristics that appeal to us? Or since it’s cats we’re dealing with; have they learnt to use their powers for evil and subconsciously manipulate us?
This new research repeated the same experiment as before, except this time they examined cats. If it ain’t broke, don’t fix it!
The researchers visited more than 100 members of Felis catus in shelters around the UK. Whilst being recorded, the experiments went up to these animals as though they were looking to adopt. How the cats behaved was carefully documented and rigorously analysed. Everything from the shape of their mouth, proximity to door, tail position, and dozens of other characteristics.
(as an interesting aside, this was the first time such a rigorous methodology has been applied to cat faces; leading to the formulation of a new method the authors label “catFACS” after similar approaches applied to other animals. Whilst that is a very sensible name with scientific precedence and a good acronym, catFACS just makes me think of cat facts; and the hilarious image below)
After carefully documenting how the cats behave, they then examined how long it took for them to be adopted. A correlation between a particular cat behaviour and a faster adoption would be a strong indicator natural selection was driving the felines to become more appealing.
By now you’re probably on the edge of your seat. So which cat facial expression tricks humans into accepting them as their dark overlords? Unlike dogs
Unlike dogs, it turns out none of the cat expressions was correlated with adoption. None of the noises they made had an impact either. Not even the cutest meow could persuade humans to pick a cat. However, one feature was strongly linked to adoption rate: rubbing. The more cat rubbed their face on someone in a friendly way; the quicker they were adopted. A few other variables were also linked to adoption rate, such as where the cat sat in their chamber, but these seem to be correlated via rubbing (i.e. cats sitting in certain places did more rubbing).
This rubbing is a fairly friendly behaviour, being done to owners more than strangers. But in this context it was being done to strangers, suggestign the cats may be trying to be friendlier in an effort to be adopted. This could be the result of natural selection driving cats to become more appealing to humans to increase their survival chances.
As an interesting aside, they did find a few other strange variables that influenced the cat rate of adoption. People seemed to prefer male cats (which were ironically a smaller proportion of the population). Tortoiseshell cats also seemed to be adopted a bit less than often, but the rate wasn’t particularly significant.
But before we go on discussing secret cat evolution, there are some caveats. Which the researchers do a good job of pointing out. The main one big that this isn’t a new behaviour. Unlike the case with dogs, with wolves not knowing how to cutely raise their eyebrows when adults. Wild cats will also rub up against each other as a sign of affection. The transfer of this to humans (and a possible increase to appeal to humans when needing adoption) suggests there may be some ongoing natural selection influencing this behaviour.
Wild cats will also rub up against each other as a sign of affection. The transfer of this to humans suggests there may be some ongoing natural selection influencing this behaviour. However, the fact it is already present in the species makes it difficult to quantify just how significant the impact of any evolution is. There might not be any, beyond the forces which initially drove its domestication.
What’s far more interesting is how facial expressions don’t seem to matter. Humans are driven by faces, to the point where we even spot them where they aren’t. But to ignore them in our feline friends? Seems odd. Or maybe we just know that if we spent too much time looking a cat in the eye, we will see pure evil staring back.
Caeiro, C.C., Burrows, A.M. and Waller, B.M., 2017. Development and application of CatFACS: Are human cat adopters influenced by cat facial expressions?. Applied Animal Behaviour Science.
Waller BM, Peirce K, Caeiro CC, Scheider L, Burrows AM, et al. (2013) Paedomorphic Facial Expressions Give Dogs a Selective Advantage. PLoS ONE 8(12): e82686. doi:10.1371/journal.pone.0082686