Why does a cat hiss?

It seems likely that the similarity between the hiss of a cat and that of a snake is not accidental. It has been claimed that the feline hiss is a case of protective mimicry. In other words, the cat imitates the snake to give an enemy the impression that it too is venomous and dangerous.

The quality of the hissing is certainly very similar. A threatened cat, faced with a dog or some other predator, produces a sound that is almost identical to that of an angry snake in a similar situation.

Predators have great respect for venomous snakes, with good reason, and often pause long enough for the snake to escape. This hesitation is usually the result of an inborn reaction. The attacker does not have to learn to avoid snakes. Learning would not be much use in such a context, as the first lesson would also be the last. If a cornered cat is capable of causing alarm in an attacker by triggering off this instinctive fear of snakes, then it obviously has a great advantage, and this is probably the true explanation of the way in which the feline hiss has evolved.

Supporting this idea is the fact that cats often add spitting to hissing. Spitting is another way in which threatened snakes react.

Also, the cornered cat may twitch or thrash its tail in a special way, reminiscent of the movements of a snake that is working itself up to strike or flee.

Finally, it has been pointed out that when a tabby cat (with markings similar to the wild type, or ancestral cat) lies sleeping, curled up tightly on a tree-stump or rock, its coloration and its rounded shape make it look uncannily like a coiled snake. As long ago as the nineteenth century it was suggested that the pattern of markings on a tabby cat are not direct, simple camouflage, but rather are imitations of the camouflage markings of a snake. A killer, such as an eagle, seeing a sleeping cat might, as a result of this resemblance, think twice before attacking.