Researchers have placed a hamster wheel in a forest. It then turned into a funny amusement park.

News JVTech Researchers have placed a hamster wheel in a forest. It then turned into a funny amusement park.

But why do hamsters and mice run around on wheels all day long?

The experiment we are interested in today is not new (it was carried out between 2009 and 2013 and the results of this
study
have been available since 2014, an eternity on the scale of the internet and social networks), but it is currently experiencing a little buzz on Twitter and we thought it was nice to relay it here.

It was in 2008-2009, therefore, that Johnanna H. Miller and Yuri Robbers, a couple of Dutch researchers from the LUMC university hospital (Leids Universitair Medisch Centrum), the equivalent of a CHU here in France, s is asked this singular question: “But why do rodents locked up in laboratory cages run?”. Do they do it for fun? Because they are stressed? Because there’s a food reward at stake? And would they do it too, if they were completely free of their movements, in the middle of nature and without any pressure or reward? This is the whole point of this study.

Spinning wheels 24 centimeters in diameter in the middle of nature

To carry out their experiment, the two researchers thus decided to place two cages in nature, with the doors open, a wheel 24 centimeters in diameter and a plate of food, just to attract onlookers passing by. Obviously, the cages were not placed at random, the first was installed at the top of a dune, away from any human presence, while the second was in a clearing filled with bushes and infested with small rodents.

So as not to miss anything of their experience, the researchers also trained small cameras with night vision and an infrared motion sensor on the cages. This is how they were able to recover no less than 200,000 recordings in 4 years from which they were able to extract a whopping 12,000 video clips. It then took them about a year to deliver the analysis of their experience.

Mice, shrews, snakes, snails, slugs or even frogs, a real amusement park for animals

What have we learned from the video clips recorded during this experience? Well, to the researchers’ surprise, rodents (hamsters, rats, mice, shrews, etc.) really like running in wheels and they want more!

Of all the voluntary participants (and volunteers) in this experience, there are notably traces of snails, slugs, but also frogs or even snakes, probably more interested in self-service prey than in the 24-hour tour of the Dune cage… But in nearly 70% of cases, the participants were… mice. They are the most assiduous at the gym!

Observations showed that wild mice ran on the wheels throughout the year, increasing steadily in late spring and peaking in summer in the green urban area.

Some animals seemed to use the wheel inadvertently, but mice and shrews, rats and frogs have been seen leaving the wheel and then returning to it after a few minutes to operate it.

The conclusion of the researchers is formal, in these specific cases, the use of the wheel was intentional.

If in the vast majority of cases the participants only did a few laps of the wheels, for a period that was ultimately quite short, in 20% of cases, the mice ran for more than 60 consecutive seconds. Like that, for no reason, simply for pleasure and desire. A rodent marathon runner was even observed running in the wheel for… 18 minutes without stopping!

Little by little the researchers stopped placing food, and if the night raids then naturally decreased, a large part of those who came for the first time continued to come regularly for a little ride at the Disneyland in the forest. . And the popularity of the small rodent playpen has continued to grow, even with the youngest rodents who have never experienced the food plates of the beginning.

That’s all well and good, but what is the conclusion of this beautiful story?

The study, published many years ago on The Royal Society website, shows us that running in a wheel is a kind of “rewarding behavior” for animals and “probably not motivated” by stress or anxiety.

If in laboratories these types of wheels are generally used to study how activity levels influence the body, one is entitled to wonder if their use is not the result of stereotypes or neuroses resulting from their captivity. Here, the study suggests rather the opposite, namely that it can be voluntary.

But then, why do rodents, and more specifically hamsters and mice, run in wheels?! To really know, you’d have to be able to ask them, but as it stands, the study suggests that:

The existing explanations are that running on a wheel is a consumptive behavior that satisfies a motivation like playing or getting away from it or that it is related to the metabolic system…like a motor response to hunger or the search for food.

Wheeling can be experienced as a reward, even when no food is at stake: Running on wheels can be a voluntary behavior for wild animals in the wild.

The full study is available at
The Royal Society website.