Wild Wheels: Dutch Study Finds Wild Animals Run in Nature

Dutch researchers placed a 24-cm wheel in a natural urban area and found wild mice were the main users (88% of wheel events), with rats, shrews, frogs, and even slugs also using it. Over more than three years they logged over 200,000 visits and 12,000 video clips, showing wheel running occurs in the wild and isn’t merely a captivity artifact. The study suggests wheel-running may reflect natural motivation—possibly metabolic reward, play, or exploration—and varies with season, with implications for how we view lab mice and animal welfare.