Sometimes domestic cats make a silent hiss. Some cat owners want to know why they do it. Perhaps they know that the domestic cat hiss is an act of “protective mimicry”. It is meant to replicate the hiss of a snake and cats may even combine it with a spit just like snakes. Further, the tabby cat when curled up sleeping looks like a snake so you can understand the evolutionary origin of the cat hiss.
The reason why a hiss may come out silently is because it is instinctive and even when communicating with their human companion and owner they may hiss but it is a half-hearted version which renders it silent. A cat may hiss at their owner because, for instance, they think that their food is going to be stolen from them. The cat feels threatened.
An example of when a domestic cat might perform a silent hiss is if she brings in a mouse and their owner tries to get the mouse off them. Their cat might growl and produce a silent hiss. It may come out at any time when the owner or another person performs an action which gives the impression to the cat that the person is a predator and threatening them. Taking their food as mentioned above is a good example because predators scavenge the prey of cats. This certainly takes place a lot on the plains of the Serengeti in Africa when lions kill prey and scavengers such as hyenas trying to get off them.
However, it is not quite the same thing in a human home, in suburbia but a cat may instinctively feel threatened and the reason might not be entirely clear. It might be a toy rather than food that a person wants to take off the cat. Under these circumstances a cat might regard the toy as a prey item and therefore if there are efforts to remove it from the cat it will feel as if a predator is stealing their prey animal.
I stress: the reason why the hiss might be silent is because it is not full-blown but are curtailed, slightly ambivalent version of the genuine thing. This ambivalence may come about because the domestic cat has lost some of their wild traits when behaving as a true domestic cat.
I would help to try and work out what happened to cause it because it means that the cat is upset about something and we all want to ensure our cats are content and that they feel safe.