Pet mice kept in cages need to move more than the enclosed space allows, so their owners install exercise wheels. If the rodents want to exert their natural instinct to run around, they do it on this device. Here’s a curious twist: a team of Dutch researchers has discovered wild mice also enjoy using exercise wheels. They have plenty of room to roam, but when they find the wheels in the wild, they hop on and go for long spins. Avoid behavior like that. Soon you will ramble through more spacious places. When you do, don’t act like you do when freedom is limited.