As soon as the puppy is born , the puppies emits moans and barks. These sounds allow him to establish contact with his mother or even to express his distress if he moves too far away from her. 

Later, the moans will be especially emitted by the dog when he is in pain or fear. If he bows to a dominant dog, he may also moan.

When he grows up, the puppy's repertoire is enriched! He learns to bark but also to bark, growl, howl Barking begins around 2 to 4 weeks of age. At first, it's just a matter of barking to get others to take notice. Aggression or warning barks do not start until they are 12 weeks old. The meaning of barking is interpreted by looking at the overall posture of the dog, the position of its ears, its tail, etc.

Grunts and growls are frequently associated with aggressive or defensive behaviours. They are often heard when dogs play with each other and try to establish their dominance. The dog growling when baring its teeth announces an imminent aggression.

Only certain breeds of dogs howl: Nordic dogs for example. These wolves and sled dogs, howls are used to communicate at great distance. There are also dogs that howl in distress whenever they are alone. This can then reflect a very pronounced anxious state of the dog.