The reasons why hamsters sleep all the time and are not active:

1. Hamsters need to sleep 15-20 hours a day, and hamsters are nocturnal animals and have a different schedule than humans. Therefore, when the owner sees the hamster, it will sleep all the time and not like to move.

2. When a hamster catches a cold, drowsiness will also occur. This is because the hamster's body becomes hot, its mental state is depressed, and it begins to anorexia, resulting in a decline in body function and the hamster's lack of willingness to move. Breeders need to treat their hamsters promptly to prevent the cold from worsening and becoming life-threatening.

3. When hamsters are unfamiliar with the breeding environment, they will sleep all the time. This is because hamsters lack a sense of security and feel scared, so they use sleep to escape.

4. When the temperature of the breeding environment is too low, the hamster will enter a hibernation state. At this time, the hamster will sleep the rest of the time except drinking water. The owner can place the hamster in a higher temperature environment, and the hamster will wake up after a period of time.

5. When the breeder feeds too much every day, the hamster will feel full, which will cause the hamster to be lethargic.