DEVELOPMENT OF VOCAL COMMUNICATION

  From birth on, both wolves and dogs are very vocal. Newborn pups moan, squel, and scream as they wiggle around and compete for the mother's nipples.

Early Vocal Signals
( Squeal / Scream / Yelp / Yawn ) 

Pups squeal and scream during their first few weeks of life, but rarely by 5-6 weeks of age. These sounds are short, harmonic, and high-pitched. Screams are generally higher-pitched, much louder and less frequent. Squeals are not associated with any particular pup or adult behaviour, and adults appear to ignore them. When pups scream, their mother grooms them or repositions them, often eliciting more screams. Scream serve as a mild distress calls.
Pups yelp when stepped on or being carried, and their mother responds promtly by attending to them.Yelps are rare, brief, loud sounds.
Yawns are sounds produced during yawning and have no apparent social role.

Early Adultlike Vocal Sounds
 ( Moan / Whine / Growl / Bark )

Moans are most common pup sound.Moans, like squeals, screams, and whines are most common during first two weeks of life when pups are deaf. Pups moan while nursing, asleep, or resting; their moans do not elicit any overt response response from the mother. Pups also moan when huddled together, providing a possible tactile signal to the littermates. 
Pups also whine from birth on. Whines are higher-pitched than moans. Pups whine and moan in the same contexts, so the two vocalizations may carry similar information.
Pups growl as early as a day, but not frequently until their fourth week. During the first 3 weeks, pups may growl when huddled. Older pups growl during active interactions with litermates. Pups also bark in response to sounds outside.



Late Adultlike Vocal Signals
( Woof / Squeak ) 

Pups woof from their third week on, most often during their mother's absence. Woofs are associated with both hesitancy, and aproach and reflect uncertainty. 
Pups do not squeak until day 15, by by the week 4, squeaks become the most common sound in the pups repertoire.  
In weeks 3 and 4, pups squeak while in contact with one another but not interacting. During the next 2 weeks, they squeak mostly during interactions with littermates or with their mother. 

The Neonatal Vocal Repertoire 

The vocal repertoire of newborn pups begins to give way to an adult - structured repertoire shortly after the pups can see, hear and move about. Four most common sounds of newborns ( moans, whines, squeals, screams ) are made repeatedly during first 2 weeks of life, then decline rapidly or disappear entirely. Together with the yelp, these four sounds provide a stepped series that permits the mother to monitor the status of her litter. The decline of these early sounds indicate that pups rapidly outgrow the need for distress signal system. By 3-4 weeks of age, pups can avoid situations that may have been life - threatening earlier. Loss of squeals and screams still leaves moans, yelps and whines to indicate low, moderate or high level of distress. 
At 1-3 weeks, before the development of social behaviour, pup signals primaly serve to indicate distress. After 3 weeks of age, these vocal signals assume their adultlike roles. These are mainly used by wolves in a form of howls.