* Increased appetite: Gerbils may eat more food than usual during pregnancy.
* Nesting behavior: Gerbils will start to build a nest out of nesting materials such as hay, paper, or fabric.
* Lethargy: Gerbils may become more tired than usual during pregnancy.
* Swollen belly: The gerbil's belly will become swollen as the pregnancy progresses.
* Darkening of the nipples: The gerbil's nipples may become darker in color as the pregnancy progresses.
* Milk production: The gerbil will start to produce milk a few days before giving birth.