The internet tells me that certain sounds, in this case the sound you can make when you run your thumb along the teeth of a comb, causes some cats to initiate the gag response or gag reflex. Here is the video:
The reason the lady who made the video gives is incorrect in my view (but see below). So what is the reason? In humans the gag reflex prevents something from entering the throat and is stimulated by touching the back of the mouth. Sometimes, very rarely, I automatically initiate the gag reflex when I cough a lot. The point I am making is that the reflex is not always kicked off by putting a finger down your throat.
But….why does this particular sound made with a comb cause this response? For me it is similar to old cats having minor fits when they hear certain sorts of sharp sounds. I don’t know the answer for sure but I am tempted to conclude that this is about brain function and the sound tweaks the brain.
My guess is that the gag reflex in this instance is not typical, by which I mean to stop something going down the throat, but a very minor version of a fit.
Other, similar sounds cause the same behavior:
There may be a connection, as the lady says, with the vibrissae (the whiskers). These are very sensitive. The buzzing sound might stimulate the cat’s whiskers. This may send a false signal to the cat that something is in his mouth. But I don’t think this is what is happening. As mentioned I see the gag reflex in this instance as a non-useful or non-purposeful automatic reflex caused by certain sounds. In some older cats these sounds cause full-blown fits but in younger cats it causes the gag reflex.
That leaves us with the question, why does it happen? The answer may throw a lot of light on how the domestic cat perceives his/her environment. Anyone got any good ideas?