Yuki's mouse

One of my favorite students has two cats and they have a lot of mice. I've never met these cats but I feel close to them in any case. These cats are possessive of their mice, and their balls and other toys, and they like to hide them around the house. Do they ever find them again? Maybe not. But they know they're there somehow.

The possessive is almost always made this way: Yuki's mouse. We don't say the mouse of Yuki. People would understand us, but it wouldn't be the best way. We say, David's blog. My sister's house. My daughter's shoes. My best friend's wedding.

The plural of mouse is mice. I don't know why. Yuki's mice are hidden in many places. In this way she can always have another one, Yuki's new mouse...