I wonder if Vivia has an affinity for rodents that can fit in small spaces. (Like mice)

Vivia would make friends with anything living in the walls, they don't bother him while he reads. He may be a metaphorical cat, but he won't chase away any rodents. Zilch would've gotten along with him very well *coughs in my crack ship*. I'm sure that the animal detective has some pet mice they'd enjoy playing around with together. Free entertainment!