The characteristics of a healthy mouse
The laboratory mouse’s closest genetic relative is the wild mouse: Mus musculus. Knowledge of the behavior of the wild species provides information which is helpful in assessing the well-being of a laboratory mouse.
The way in which a laboratory mouse can engage in its natural behavioral repertoire (e.g. nesting behavior) 
, determines in no small measure its state of well-being. Multiple strains of laboratory mice are available, both inbred and outbred stock. Genetic modification technology has greatly expanded the number of available lines. Consequently, there is a great diversity in behavioral characteristics and a broad range of physiological normal values.
Mice have a short lifespan with an associated high metabolic rate and rapid maturation and reproduction. In general, they have large litters. A healthy laboratory mouse is alert, curious, engages in social interactions, looks well-nourished and clean, and is vivacious. 
 |
 |
| Healthy and alert mouse |
Diseased mouse |
