When selecting a gerbil, it is generally recommended to adopt more than one at a time, as this lends to improved social interaction, and a healthier gerbil. When choosing from the litter, a gerbil should not demonstrate fear of humans, nor should you choose a gerbil from a cage where there is a sick animal. Therefore it is best to choose gerbils that have already been caged together, or that at least six to eight weeks old. Home made gerbil cages are relatively easy to make, often by using an old aquarium, or a cage from another animal, such as a hamster. Gerbils will attempt to chew through plastic cages, and may get sores, so these are not highly recommended.
Gerbils are very territorial, and can be quite aggressive to unfamiliar gerbils. If either gerbil is over eight weeks old, they should be introduced to each other using the split cage method. This method intends to introduce the rodents to each others’ scents while preventing fights. First, find an old aquarium tank - if possible with a division already inside. If this style is not found, a home made division can be just as effective. To make a split cage, purchase some ¼ inch to ½ inch wire mesh or cloth, and place it in the middle, securing it at the corners. Then furnish the cage with the litter. You should watch the gerbils after this has been installed, as they will try their hardest to get under or around the mesh to get to the other gerbil.