how do mice change as they get older?

Question: how do mice change as they get older?
- Keywords:
  mice
Asked by Dan to Sara on 18 Nov 2015. This question was also asked by Mil99.
- Sara Falcone answered on 18 Nov 2015:
  
  Hello Dan 🙂
  
  So first let me start saying that the mice I work with are a bit different from the mice in the wild so they might age a bit differently (also because the average life span of a wild mouse is 6 months… not really much time to change >_<).
  Our mice usually gain weight, some even quite a lot, and become lazier. Some of them go a bit grey around their noses or on the belly. Also when mice are young they pee always in the same spot in their cage (so you, know, the cage stays cleaner – clever mousey!), when they get all they don't do it anymore.

Question: how do mice change as they get older?