Because of the burrowing nature of your gerbil, the bedding that lines your gerbil’s cage plays an important role. The best types of lining to use are aspen, Carefresh or corncob. Aspen has been known to cause allergies in gerbils, though, so discontinue use if you notice your gerbil’s nose is irritated. Shredded paper also works, but it will start to smell more quickly.
Be sure to avoid soft wood shavings such as pine or cedar because these can cause respiratory problems and liver damage, especially in pups. Commercial nesting material made from cotton or loose fibers is also not recommended because the gerbil can ingest it or get caught in it and break an appendage.
Fill the cage about a third full with the bedding material. This will allow plenty of room for your gerbil to burrow and play. However, if breeding, the cage only needs about 2 inches of material.
Another thing to keep in mind is that by providing more bedding you are recreating your gerbil’s natural environment. Sometimes too much bedding will cause it to go wild. If this occurs, adjust the level of the bedding to encourage more tame behavior.