How Does Your Pet Really Feel about That Exercise Wheel?

If you've ever owned a pet hamster or gerbil, you'll be familiar with the constant squeaking of the exercise wheel. Captive rodents, including laboratory mice, seem to be capable of running on these wheels for hours on end. But do they actually enjoy running in place, or are they simply exercising out of sheer boredom? Now, thanks to a team of Dutch researchers, we might know the answer.

While studying the circadian rhythms of animals in the wild, a research team from Leiden University Medical Center decided to conduct a secondary study by setting up exercise wheels in the urban and rural sites the creatures were frequenting. By installing video cameras, the scientists were able to watch the running wheels throughout the day and night, and it turns out that the mini-gyms attracted quite a few new members.

Not only did hundreds of mice stop by to take a spin on the wheel, but it was also used by rats, voles, shrews, frogs, and even snails. While the statistics weren't staggering -- most of the animals didn't partake -- there were still plenty of rodents choosing to use the wheel for a minute or more. Lead researcher Yuri Robbers said he believes the concerns about mice running because they are stir-crazy appear unfounded. "It seems that they see the running as rewarding in itself, or maybe as a form of play," he said.

More about mice:

• Mice and rats learn as quickly as dogs, and despite having poor eyesight, they remember a correct path forever after finding it.
• Although some mice can grow to 7 inches (17.8 cm) in length, the smallest mouse is the African pygmy, which rarely exceeds 3 inches (7.6 cm) and weighs only about .35 ounces (10 grams).
• Despite what cartoons suggest, mice don't like cheese; they prefer grains, seeds, and fruit.