It has been suggested that cats actually began hissing after hearing snakes hiss. This behavior may actually originate from imitating snakes. Your cat might really be a copy cat! Because snakes can be so deadly, other animals know to pay attention and shy away from its characteristic hiss. The hiss is a warning to other animals or people to stay away, whether it comes from a snake or an unhappy cat. A cat’s hissing is often a result of fear. The introduction of another animal into the home, for example, another
cat or a dog, is a common reason for a cat to hiss. Anything or anyone a
cat doesn’t know scares it and so it hisses as a defense mechanism. Source: omgfacts