I've recently adopted a deaf kitten (two days ago). She doesn't respond to any sounds, but she does respond to my senior non-deaf cat hissing and growling (I'm slowly introducing them).
Is it possible that our deaf kitten can sense the growl/hissing? They don't even need to be in eye-shot of each other. The senior cat hears the kitten's bell and growls, and the kitten can pick up the growls/hissing and responds with her own growls. Could someone maybe explain this?
She may not be able to necessarily hear the growling and hissing, but she may be responding to the non-verbal body language the older cat is using to indicate her displeasure.
For example, the older cat's face is not going to look happy - so she could be responding to the way the cat's face looks angry, or how her body is positioned - there is so much more to communication than just the sound.
It's the same as human communication - even if you can't hear my voice, the my facial expressions or my body language can often indicate my mood.
I would suspect that your kitten is picking up on the other, non-verbal communication exhibited by the other cat, such as the motion of her tail (lashing, bristled, etc), her face (she may recognize the hissing/growling face), the "puffing" of the older cat's body/fur, etc.
