Why Do Cats Hiss? Animal Mimicry
The generally accepted answer to the question, why do cats hiss, is that the cats are mimicking snakes. It sounds far out, but it makes some sense too, it is a natural instinct for cats to hiss when they are about to go on the defensive, just like snakes will do.
A snake in the wild will oftentimes stand up and hiss as a warning, think of the cobra in the Indian jungles, that is what they will do; a rattlesnake will do this too, and at the same time they will shake and rattle their tails. Have you ever noticed a cat do this somewhat as well? Cats will often hiss and slowly shake their tails as their own warning to back off.
When we think about it, cats even look somewhat snakelike, it's in the eyes. Genetically cats and snakes do have some similar traits and it's been postulated that if we went far enough back into history that cats and snakes do have similar origins.
Is all of that hissing an embedded natural instinct that goes back millions of years into the past? While we can't be exactly sure, the hypothesis sure seems to make a whole lot of sense.
Whatever the case may be, when a cat hisses it wants you to back off. And it's best that you do so because getting a cat bite could land you in the ER faster than you can whistle Dixie.
Other things to watch out for when a cat feels threatened or is angry is fluffed up fur, drawn fangs, a menacing facial expression, and the slow waving of the tail. When they do this they are either frightened by something, or are simply protecting what they see as their territory, or in the case of the new mother, protecting her kittens. Whatever the case, back away or you could definitely receive a nasty scratch or bite. Sometimes when cats hiss, they will also sort of growl, it depends on the cat, those are all things to be on the lookout for.
Another possible reason of why your cat is hissing could be that they are sick or even mentally unbalanced (if it happens to the best of them). If this hissing and freaking out keeps happening for no apparent reason, they please take them to see the vet right away they could be very sick.
We all want our cats to be obedient little guys who love to purr and cuddle, and hopefully your cat acts this way most of the time. They should. If you cat is mad and hissing all the time there's a big problem that isn't being addressed somehow. There you have it, now you know the answer to the question-why do cats hiss-now, if you could only get them to pee in the litter box all the time.