Kostya continued growling but by now even more of his aggression had trickled away. At this point his heart wasn't really in the fight anymore, and his aggressive stance was mainly just to keep up appearances. His initial response had been more spur of the moment than born out of an actual desire to fight and it was clear that the smaller wolf was a much more skilled fighter than Kostya himself.
That being said he remained tense and weary, ready to react if the stranger attacked him again, while he knew he was outclassed he didn't intend to do down without a fight if this lack of aggression was a trick. This time when he spoke his voice was less aggressive, and less fearful, "What're ya' doin' roun' ere' then? Mos' wolves tha' I know, know not ta' bother someone in their den unless they're lookin' ta' drive em' out."
Kostya took the insult about exercise in stride, subconsciously acknowledging the truth of it, but the females last insult caused him to let out an amused snort, "Bulky? Ya' say that like it’s a bad thing, I'll sure be enjoyin' tha' winter more than a scrawny little thing like you." Despite the insult Ksotya's voice wasn't particularly aggressive or mocking, instead it has a quality of curiosity to it, as he was trying to puzzle out the coywolf's reaction; see if she could take insults as easily as she gave them.