It had taken a while, but Blue had managed to categorise most of the pets in the city. She knew which ones belonged to which packs and which were just small, singular pets. She assumed they were meant to protect the ones without a pack, until they found their own packs. Even the ones in packs were so very poorly looked after sometimes.
This one was one of the singles, and Blue realised that she smelled largely familiar because the female shared space with her when she went to her big building. So, not a threat. It didn't lessen Blue's protective stance of the Alpha and his mates den though. If someone could snatch away their female without the alpha noticing, Blue was going to be largely more diligent in her watching.
Huffing in annoyance, Blue just stood her ground. Tail swaying and arms tucked in so her claws weren't too threatening, she maintained her defensive post and watched the pet with a tilt of her head.