Most dogs get noisy when exposed to anything new or unusual.
The stimuli that trigger noise can vary for dogs and includes barking, whining, growling, or howling. Whenever growling or barking is successful at achieving the pet's goals, the dog feels rewarded. Subsequently, the growling will likely become more frequent or intense. Medical problems can contribute to vocalization, and senile changes may lead to barking problems in older pets. In some cases where barking becomes intense, repetitive, and difficult to interrupt, it may be deemed compulsive.