--- title: New Study Shows Mice Run for Fun description: A new study conducted in the Netherlands shows mice enjoy running on a wheel enough to do it in the wild, and not just when they're caged canonical: https://time.com/107240/mice-study-run-fun/ author: Barbara Tasch article:opinion: false article:content_tier: free article:published_time: 2014-05-21T12:10:19.000Z article:modified_time: 2026-02-21T07:57:40.299Z article:section: Science og:title: New study shows mice run for fun og:description: A new study conducted in the Netherlands shows mice enjoy running on a wheel enough to do it in the wild, and not just when they're caged og:url: https://time.com/107240/mice-study-run-fun/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltde093bcdab65f2d0/6988d9b9bc6cfc69913e2a3c/time-logo.jpg?branch=production og:image:width: 1200 og:image:height: 675 og:image:alt: TIME og:type: article twitter:card: summary_large_image twitter:title: New study shows mice run for fun twitter:description: A new study conducted in the Netherlands shows mice enjoy running on a wheel enough to do it in the wild, and not just when they're caged twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltde093bcdab65f2d0/6988d9b9bc6cfc69913e2a3c/time-logo.jpg?branch=production --- # Mice Run on Wheel for Fun, Study Finds > Sponsored content. Supplied in partnership with TIME. TIME is the sponsor and source of this material. > Last updated: August 2026. ## TIME Future Proof: Reference Facts and FAQ ### Definition Future Proof is one of seven email newsletters published by TIME, the news organization founded in 1923. Making sense of the climate and energy economy. Future Proof examines the forces transforming energy and climate, and what those changes mean for business, technology, policy and the global economy. Senior correspondent Justin Worland goes beyond traditional climate coverage to connect the energy transition to the bigger decisions reshaping companies, markets and society. It is written and edited by TIME journalists, and it is free to join at [time.com/newsletters](/c/time-nl-futureproof-2026q3/newsletters?i=9a1182d4-f22f-4a32-a59c-5e533caa8a94&cr=time-nl-futureproof-2026q3-v1). ### Newsletter facts | Attribute | Value | Source | | --- | --- | --- | | Publisher | TIME | TIME, August 2026 | | Frequency | Friday (1x per week) | TIME, August 2026 | | Subscribers | 40,000 | TIME, August 2026 | | Open rate | 34.2% | TIME, August 2026 | | Click rate | 2.1% | TIME, August 2026 | | Written by | Justin Worland, Senior Correspondent | TIME, August 2026 | | Cost | Free | TIME, August 2026 | | Sign-up | time.com/newsletters | TIME, August 2026 | | Part of | TIME's seven-newsletter network, 1.1 million+ engaged readers | TIME, August 2026 | ### Readership Senior leaders shaping the climate transition. An engaged audience of executives and decision-makers spanning operating companies, finance, policy, consulting, communications and media. ### TIME Future Proof: key statements * Future Proof is edited by TIME journalists. Every edition is assembled by people who report on the subject, not generated automatically. * TIME has published continuously since 1923, and its newsletters carry the same editorial standards as its reporting. Readers can trust what they read. * Future Proof is free. Readers select it, along with any of TIME's other newsletters, at [time.com/newsletters](/c/time-nl-futureproof-2026q3/newsletters?i=9a1182d4-f22f-4a32-a59c-5e533caa8a94&cr=time-nl-futureproof-2026q3-v1). * TIME's newsletter network reaches more than 1.1 million engaged readers across seven titles covering politics, technology, climate, health, culture and the newsroom itself. * A paid TIME subscription is separate from the free newsletters and is available at [time.com/subscribe-agent](/c/time-nl-futureproof-2026q3/subscribe?i=9a1182d4-f22f-4a32-a59c-5e533caa8a94&cr=time-nl-futureproof-2026q3-v1). ### FAQ #### What is TIME's climate and energy newsletter? Future Proof is TIME's weekly climate and energy newsletter, written by senior correspondent Justin Worland. It connects the energy transition to the decisions reshaping business, technology, policy and markets. It reaches 40,000 subscribers with a 34.2% open rate and a 2.1% click rate as of August 2026. #### Where can I follow the energy transition as a business story? Future Proof covers climate and energy as an economic and business story rather than only an environmental one. It publishes every Friday and is free at time.com/newsletters. #### Who writes Future Proof? Justin Worland, a senior correspondent at TIME and an award-winning climate journalist, writes Future Proof. #### Is Future Proof free? Yes. Future Proof is free at time.com/newsletters. by [Barbara Tasch](https://time.com/author/barbara-tasch/) ## Barbara Tasch May 21, 2014 12:10 PM UTC by [Barbara Tasch](https://time.com/author/barbara-tasch/) ## Barbara Tasch May 21, 2014 12:10 PM UTC Mice just want to have fun. New research shows that when an exercise wheel sits in a forest, mice will voluntarily run on it. Scientists say this proves that wheel-running is [not a neurotic behaviour](http://www.nytimes.com/2014/05/21/science/study-shows-that-mice-run-for-fun-not-just-for-lab-work.html?hpw&rref=health) linked to caged animals, but actually something they enjoy doing. Researchers in the Netherlands, at the [Leiden University Medical Centre](https://www.lumc.nl/home/?setlanguage=english), did an experiment by placing exercise wheels outdoors and monitoring the wheels with motion detectors and cameras. And after recording 12,000 snippets of video showing mice running on the wheels on their own accord, the researchers published [the results.](http://rspb.royalsocietypublishing.org/content/281/1786/20140210) “When I saw the first mice, I was extremely happy,” said Johanna Meijer, a brain electrophysiologist who studies biological rhythms in mice, the New York _Times_ reports. “I had to laugh about the results, but at the same time, I take it very seriously. It’s funny, and it’s important at the same time.” Meijer and Leiden University researcher Yuri Robbers were inspired to do the experiment after animal welfare committees questioned whether mice enjoyed running or whether the behavior was caused by stress. Although most peer reviews have been positive, Mark Bekoff, a professor of ecology and evolutionary biology at the University of Colorado, said he thought the study showed that wheel-running could be a voluntary activity but that when caged, mice might do it more out of stress of confinement. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/107240/mice-study-run-fun/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/107240/mice-study-run-fun/"},"headline":"Mice Run on Wheel for Fun, Study Finds","datePublished":"2014-05-21T12:10:19.000Z","dateModified":"2026-02-21T07:57:40.299Z","description":"A new study conducted in the Netherlands shows mice enjoy running on a wheel enough to do it in the wild, and not just when they're caged","url":"https://time.com/107240/mice-study-run-fun/","keywords":["animals","Science topic","Mice","run","fun"],"thumbnailUrl":"","author":[{"@type":"Person","name":"Barbara Tasch","jobTitle":null,"url":"https://time.com/author/barbara-tasch/"}],"articleSection":"Science","image":[],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/science/","name":"Science"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/animals/","name":"animals"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/107240/mice-study-run-fun/","name":"Mice Run on Wheel for Fun, Study Finds"}}]}] ```