A Cossack Companion

While posting about the 'Cossacks letter to the Sultan' I noticed this dog, listening with a rather irritated expression on his face, to the banter at the table. 

I haven't noticed him before. What is he there for? Is it a symbol, a metaphor, or just a colourful detail? Maybe it's a reference to the terrible Sultan himself?

And what breed is he? Doesn't look like a sheep dog (where is the flock?) or a guard dog (who is there to guard in the middle of the cossack town?).  Could it be their idea of a companion dog?