My old guy lost his hearing, probably around 27 years old. I have one now that is 21 and he seems to be getting hard of hearing so I've started pointing when I want him to move somewhere along with using the words he's used to. I figure by the time his hearing is gone he'll know what the pointing means. The vet didn't seem worried or think it was out of the norm back when JC went deaf. I think animals suffer from some of the same old age ailments that people do. I have 2 cats that are 15 who've lost their hearing too.