"gnu's getting so old that he probably can't hear the full frequency range of a talking teddy bear"

It isn't true that age and deafness must go together. Many old people have fine hearing. Much of hearing loss has to do with noise from industry and - nowadays - amplified music.

My mother (who never drove a car and rarely worked outside the home)went for a hearing test at age 70 or 75. The audiologist said she had the best hearing he had ever tested.

We never went in for loud music, either.