Normal
It is a normal behavior for hamsters to run on the wheel at night, which is determined by their nature as nocturnal animals. Here is a detailed explanation of this phenomenon:

1. The Nocturnal Characteristics of Hamsters
Hamsters are typical nocturnal animals. They usually sleep during the day and become active at night. Running on the wheel is an important way for them to release energy and exercise.
2. Reasons for Running on the Wheel
Exercise Requirements: Hamsters need a lot of exercise to burn calories, and running on the wheel is their main way of exercising.
Adapting to the Environment: Hamsters in a new environment may run on the wheel to adapt to it.
Emotional Release: When hamsters feel stressed or unhappy, they will also run on the wheel to release their emotions.
3. Precautions
Time Control: Although running on the wheel is a normal behavior, don't let the hamsters run for more than 6 hours to avoid excessive fatigue.
Safety Measures: Ensure that the running wheel is stable and noiseless to prevent the hamsters from getting injured or disturbing the owner's sleep.
Environmental Optimization: If the hamsters run on the wheel too frequently, check if there are other factors (such as cats or other pets) that make the hamsters nervous.
4. How to Deal with It
Provide Toys: Add more toys to the cage to distract the hamsters.
Adjust the Environment: Place the hamster cage in a quiet room, or use a running wheel with less noise.
Observe Health: If the hamsters have a loss of appetite or abnormal urination and defecation while running on the wheel, they need to see a doctor in time.
Conclusion: It is a normal and healthy behavior for hamsters to run on the wheel at night. Owners just need to ensure their safety and comfort.