Quote Originally Posted by .sarah
I don't think he is, but I'm not sure. I didn't pay much attention but he seemed to respond to noises.
Deaf animals learn very quickly to respond to vibrations. Best way to find out if it's noise or vibration is sneak up behind the cat, or while sleeping and clap your hands loudly, or open a can of food, or something else that should get a reaction, watch to see if the ears flick or any other indication of hearing.

We tried that on one at work that appeared to respond to noise, but found out it was simply 'feeling' the vibrations of our footsteps or opening the cage, not the actual sounds.