Mouse Health

Behavioral Disorders

Whisker biting

If you notice that one or several of your mice has lost its whiskers, there is a whisker biter in the cage. Check your mice -- the mouse who still has whiskers is the whisker biter. Usually this mouse is the dominant mouse of the group. Whisker biting is a method of suppressing other mice. This behavioural disorder may be caused by stress -- changes in the group, too many mice in the cage, or having babies. You can't take a mouse without whiskers to a show. The tendency of becoming a whisker biter is hereditary, so you shouldn't breed from a whisker biter. You can, however, have a whisker-biting mouse as a pet but preferably in its own cage.

"Jumping in loops"

Jumping in loops is a rarer behavioural disorder than whisker biter. Mouse jumps a loop by jumping upwards so that its feet touch the lid of the tank. It is rather tiresome for the owner, especially if there's a constant "bump, bump, bump" -sound coming from the mouse tank all night long. This behaviour may be hereditary or stress-related. Avoid breeding from such a mouse.


The so-called waltzers are not a different species of mice, it is a balance disorder caused by a hereditary inner ear defect or an inner ear infection. This defect causes a balance disorder, which makes the mouse to run around in small circles like it was dancing after its own tail. When the disorder gets worse, the mouse falls over because it does not know anymore which way is up and which way is down. This disorder can not be cured, so when you notice that your mouse feels bad it is better to let it out of its misery.