Cats who have been handled roughly in the past could hiss in protest, expressing their displeasure or refusal in being held or approached. Your cat is stressed and afraid:
If your cat is frequently hissing at your kitten, keep meetings short and brief, using a feliway diffuser to help them remain comfortable and calm.
Why do cats hiss at their own kittens. When exposed to a strange situation, like moving to a new home, your cat may hiss at movements, noises, and other unsettling aspects that she’s not used to. This growing aloofness is normal behavior for mother cats as their kittens begin to grow up. Although a hiss sometimes indicates that your kitty is about to attack the newcomer, it's usually just a warning for him to back off before she runs off.
Scientists who study cat vocalizations tend to view spitting as a variation on the hissing theme rather than a separate sound. Sometimes, cats even hiss at the veterinarian because they don’t like being handled, poked and prodded. Mother cats hiss at their kittens for a few different reasons.
Some cats may instinctively hiss or act assertively when you introduce a new kitten, so you’ll need to offer lots of reassurance and extra attention. As long as this doesn’t turn into a physical confrontation or your cat is too stressed by the situation this will subside when they realize there is no real threat. He hissed, spit, and arched his back.
There are quite a few reasons that mother cats will eat their newborns. Even if your cat is the sweetest little cat on the planet, if she has ever felt threatened or needed to send a warning to someone (feline, canine or human), she has probably hissed at some point. Similarly, you may notice your cat hissing a lot when you pay a visit to the vet.
Some mama cats may find that they have one kitten is either ill or not going to make. When you observe your cat hissing especially the adults, one question that might cross your mind is why do cats hiss at kittens? A cat who feels the need to take the hissing up a notch may advance to spitting.
Here are a few reasons and explanations on “why?” 😺. Social behavior sets in early, especially for felines. This is due to the feline feeling that they are in unfamiliar territory, unsure of what to expect.
A cat’s hiss sounds close to that of a snake’s or an overloading radiator. It can be very painful for cats when they experience mastitis. Finally, when kittens are weaning at about 4 weeks of age, their mother will hiss at them to discourage suckling.
Let’s say that you’ve just brought the kitten home after visiting the vet. Another is if mama is malnourished. A cat who has had little to no socialization with other cats will have a very hard time adjusting to a new housemate.
The infection from the mammary glans may be passed from the queen to the baby. “cats may hiss at new kittens to establish boundaries, generally when the established cat’s boundaries are being pushed,” adds demos. Cats also hiss at their kittens to warn them of an incoming threat.
“a hiss is a quick means to tell the kitten to stop.” what to do if your cat is hissing.  hissing is considered a “voiceless” vocalization and it is more drawn out, while spitting is an explosive burst of sound. Cats who are in pain hiss when they’re touched in a spot that hurts.
Perhaps your new furbaby is now frightened or is even responding in kind. Territorial aggression when a cat hisses at a new cat or kitten, she is expressing a form of territorial aggression. Your cats have met each other, and your resident feline became aggressive.
Sometimes cats might hiss at new kittens because the kitten smells unpleasant or strange. Primarily, mothers hiss so that kittens can learn to mimic the sound. A cat might be scared of a newcomer, and will turn to hissing and growling at the new cat as a warning to get out of their space.
The kittens’ vulnerable state may not be able to have their immune system handle it. Cat hissing is a warning, reminds demos. Their ears flatten, their spine arches to the point where furs on their back stand and their tail puff out.