The motivations of mice

8 07 2014

The next phase of Mike‘s giant enrichment study is finding out whether a cage’s degree and type of enrichment predicts how much mice want to live there. We want these data to test the hypothesis that good welfare, as induced by good housing, promotes longevity (and these data give us a way to see how much the mice value different types of living condition).

In this set up, mice are placed in a small non-enriched cage, which is connected by a single tunnel to their normal home cage (which as a rule will be enriched with running wheels, and/or treats and extra resting places). This tunnel crosses a metal grid, which every two days becomes very slightly more electrified. This is not as bad as it sounds: the currents used and their increments are absolutely tiny, and mice never have to cross if they don’t want (since water, food and bedding are available both sides of the grid). Once all 3 mice per cage have given up crossing for two days straight, they are taken out of the experiment and put back into their regular home cage. Here you can see two home cages (in this instance, home cages with orange plastic ‘satellite dish’ running wheels), each reached by a tunnel from a small non-enriched standard lab cage (in the foreground).

Hiccups so far include the videos not having decent internal timers/time stamp mechanisms (hence the cheap alarm clock ingeniously duct-taped across the home cages); the video cameras spontaneously shutting off every 13 hours, meaning that some poor soul (typically Mike) has to come in every evening just to re-press ‘record’; and the mice screwing things up by taking items from their enriched cages into the supposed barren cages (bad mice, bad!). But despite this, fingers crossed it all seems to be going OK…

mouse motivation