Why is your gerbil sleeping in the center of his cage?

Gerbils often sleep in the center of their cage because it provides a sense of security and visibility. Being in an open area allows them to be aware of their surroundings while resting. Additionally, the center may be the most comfortable spot in terms of temperature and bedding. If your gerbil is sleeping more than usual or seems lethargic, it could be a sign of health issues, so it's worth monitoring their behavior.