A "hamster wheel" is a circular exercise device commonly used for small pets, particularly hamsters. It allows these animals to run and play while remaining in a confined space. The wheel spins as the pet runs, providing physical activity that helps maintain their health and well-being. In addition to being a toy for pets, the term "hamster wheel" is often used metaphorically to describe a repetitive and unproductive routine in human life. People may feel like they are running in place, expending energy without making meaningful progress, similar to how a hamster runs in its wheel.