

Wild mice actually enjoy running on exercise wheels - mhb
http://www.theguardian.com/science/grrlscientist/2014/may/21/wild-mice-exercise-wheels-behaviour-stereotypy-neurosis

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pwg
Previous discussion is here:
[https://news.ycombinator.com/item?id=7788162](https://news.ycombinator.com/item?id=7788162)

