A cat might be anxious because of something that is happening around them or not far from them. They might be slightly afraid and the normal reaction will be to run away silently and hide. If they are walking at the time, they will lower their body to tense the muscles of their legs in readiness to spring up and run. But this is not fear. It is anxiety about what might happen.
A domestic cat might become genuinely frightened because of the animal including the human-animal that is in his presence often immediately in front of him. It might be a predator and sometimes a domestic cat views humans as predators. Humans are in fact the world’s greatest predator if we want to be totally honest with ourselves.
And if that dangerous ‘hostile’ corners them they will vocalise their fear. But it’ll a ‘qualified’ vocalisation by which I mean it is intended to state, “I fear you, but don’t push me too far because if you do, I will attack you and defend myself.” It is both a signal of fear and also of an impending attack.
This vocalisation is a throaty, yowling noise. It will vary between individual cats as all feline vocalisations do. And their ears will point backwards and flatten on their head to protect their ear flaps. These actions indicate that the cat is fearful but ready if needs to be to defend themselves.
For a domestic cat, fear does not equate to being paralysed into inaction. This can happen to people but push a domestic cat into a corner, at a certain point in time they will attack fearlessly with great aggression.
But before that final action they will deliver the usual snake sounds which are the spit and hiss. This is the final attempt to deter the aggressor on the understanding that most mammals appreciate that a snake is a dangerous creature. It is something that they have learned throughout evolution and therefore the signal transmitted with these two snake sounds is, “I am dangerous and therefore you should go and don’t threaten me anymore”.
Should that signal fail to elicit the required response from the aggressor then the attack begins. So, as you can see it is a staged buildup to the final action of physical attack with various vocalisations and behavioural postures i.e. body language.
The cats in the audio below are fighting.