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Neurophysiologists in the Netherlands have found that if you place a hamster wheel outdoors in a natural setting, wild animals such as mice will come and run on it voluntarily. This suggests that the animals enjoy the activity.

Previously it was thought by some animal rights activists that caged animals such as hamsters and mice would run in the wheels as a form of neurotic behaviour, driven by the fact that they were confined to a small space. However, some researchers had suggested that small rodents seem to enjoy running on these wheels and exhibited unhappy behaviour if the wheel was removes. Johanna Meijer and Yuri Robbers sought to put this theory to the test by set up running wheels and cameras outside (in small open-sided shelters) to see how wild animals would respond.


The researchers put a bit of food near the wheel in order to lure the animals to the right area. They found that many wild mice would find the wheel, climb on and start running. Other animals to enjoy the ride were frogs, rats and shrews: the frogs would hop from side to sort to make the wheel swing back and forth while slugs seemed to rock up to the party by accident. That's slugs for you.

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Buoyed by the popularity of the wheel among wild fauna, the researchers set up a second wheel and camera in a nearby dune area.

Over three years more than 200,000 animals used the wheels.


Activity was monitored using a small magnet attached to the wheel and a stationary magnosensor.

Some of the animals seemed to use the wheels unintentionally, but others seemed to jump out of the wheel only to return a little later for another go. The researchers think this suggests they enjoy running.

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Mice were most keen on the wheels, running for more than 1 minute in 20 percent of cases, with one mice running for an astonishing 18 minutes. The mice never walked.


The researchers were concerned that the food placed need the wheels may have induced the animals to run, so they stopped providing food near one of the wheels for more than a year and the running continued. The number of visits to the wheel did drop significantly, but the amount of wheel running activity among those animals that did visit increased by 42 percent.

The team speculated that wheel running could be experienced as "rewarding even without an associated food reward, suggesting the importance of motivational systems unrelated to foraging".

You can read the full paper, published in Proceedings of the Royal Society B: Biological Sciences here.