One cat goes belly up in front of the harp whenever it is being played. The other likes to sit on my knee and occassionally put her teeth against the vibrating strings. I think it has more to do with being involved than it does with the quality of my playing.
We don’t have animals like cats and dogs, but me and my boyfriend have noticied that the neighbourhood dogs in the park, bark and howl when I pratice… which is hilarious when it happen 😉