Mouse stops using wheel

Question
We have a wild mouse captured as what appeared to be a young adult
becuase he (or she) is blind.  He's acclimated to a 3-deck cage and
learned to run in a wheel. Doing fine for about a year now.


Watching him run endlessley in his wheel, I finally built a device,
using a reed switch and magnet connected to a dismantled computer
mouse which, when connected to my computer, measures total revs of the
wheel in an evening and max speed. The little athlete ran nearly four
miles the evning I got it working, maxing out at nearly 5 mph.

But a few nights later, he stopped using the wheel almost
completely. Just a few desultory turns in an evening.  No more furious
and prolonged running now for over a fortnight.

Any suggestion as to why he's slacking off?

One suggestion is the he's a she and the behaviour is related to
estrus but the slacking off has gone on since Sep. 3.

Answer
Hi Mike,

I just have to say - I LOVE the idea of measuring his (or her!) revolutions on the wheel, and that is just too cool!  It sounds like something my husband would rig up.  :)

Estrus in mice occurs approximately every five days, and when no male hormones from urine are present, can become absent entirely over time, so I don't believe that's what's happening here.  Instead, since it occurred just after the introduction of your device, I would wonder if he/she is irked about something to do with it?  Mice have a different hearing range than people, and if the mode of measurement is mechanical (instead of optical, for instance), it could potentially be making a noise that bothers the little guy when he runs on it.  Another possibility lies in the kind of computer you are using - some older desktop or TV monitors create an ultrasonic noise that bothers mice, so if it is running more than usual at night or when he runs on the wheel, he may be less inclined to do so.

I would personally try removing the measurement mechanism briefly and relying on something different for a couple of weeks to see if there is any change.  If so, it may just need a bit of tweaking to be less intrusive on his habits.  If nothing changes, then I'd wonder if he just happened to have odd timing with becoming bored, as mice can, and might just need a little mixup with the type of wheel, or some new things to explore to get him interested again.

I'd be interested to know how it works out, so please keep me updated!  So cool!

-Tam