Some dogs react to the sound of a piano being played by whining or howling. This behavior can be attributed to a combination of factors. First, dogs have a keen sense of hearing, and the piano's tones may evoke an instinctive response. The pitch and intensity of the piano's sound can stimulate a dog's auditory senses, triggering whining or howling.
Also, some dogs are highly attuned to their human companions and often seek attention and interaction. So, when they observe their owners playing the piano, they may interpret it as a form of communication or a call for engagement.
Specific musical notes or melodies might also create an emotional response in dogs, leading to vocalizations to express their feelings. Overall, the whining or howling at the piano can be seen as a combination of a dog's acute hearing, desire for attention, or an emotional reaction to the music being played.