Even the young wolves love their belly rubs!
Why Animals Like Tummy Rubbing
Some canine can't resist a good belly rub, and the reasons are both behavioral and neurological. While showing off his tummy is a conscious act that speaks to his relationship with you, your animal also undergoes a neurological reaction when you start stroking his fur.
The combination of the two can make tummy rubbing a wholly satisfying experience for your pet -- if he lets you do it in the first place.
When animals display their tummy for a rubdown, they are performing an act that is, at its core, submissive.
Rolling over to show you his belly leaves him physically vulnerable, and represents a strong degree of both trust in and submission to you. Rubbing his belly just plain feels good, much like other types of petting, but it also shows him that his trust and submission were well-placed, and that you won't take advantage of his vulnerability.