It should be noted that dogs specifically don’t just howl at the azan. They respond to church bells, ambulance sirens, and many loud and regular sounds. Such a perception has arisen because we see that most of the time they react to the call to prayer.
Since they howl at a religious voice, it is seen that this situation has various meanings among the people. However, when we look at the researches of scientists on this subject, it is seen that there are many natural reasons for the emergence of this situation.
They find the adhan too noisy.
This is why they react more to the morning prayer. Because when it is very quiet, the suddenly rising sound makes the dogs nervous, revealing their need to respond, and this causes them to howl in unison.
Dogs can also hear high-pitched sounds that we cannot. These creatures, whose sensory sensitivities are much more developed than ours, can be quite disturbed by the sounds of azan, ambulance and siren supported by loudspeakers.
Another possible cause could be classical conditioning. Just like with Pavlov’s dog.
Before meat was given to the dog in this experiment, the bell was ringing. The dog, who experienced this situation every time, started to drool as soon as he heard the bell, as he started to condition.
As in this experiment, dogs may immediately begin to howl when they hear the sound of azan, thinking that their ears will be disturbed. In other words, they react automatically by being conditioned thanks to what they have learned even before they are disturbed.
Howling is a warning system inherited from wolf ancestors.
When they feel they are in danger, they warn their flock. They also intimidate the enemy herd. Since they have lived with people for centuries, it is a form of behavior that arises from the synthesis of the city and nature.
Sources: 1, 2