Gerbils are social animals and live in small family groups in the wild. They will cuddle, groom, chase, and wrestle with each other. As with other social animals, e.g., wolves, there is usually one dominant pair that mates, and the older offspring help care for the young. As the offspring reach adolescence and adulthood, they leave their social group to form another.
In captivity, gerbils prefer to be in social groups as well, though it is up to the owner to keep the group at an optimal size. The Amercian Gerbil Society has made the following recommendations:
- Always introduce two strange gerbils using the split cage introduction method (described below). Young pups, sexually mature pairs, and an older male and young pup clan most easily.
- Never keep more than two adult females together
- Never keep more than four adult males together, though some have success with up to seven
- Never, ever breed more than one female in a single tank
- When a second litter arrives remove all but 1-3 older pups to keep from overcrowding
Split cage introduction method
try to introduce a new gerbil into an established group.
Gerbils are very territorial, and will be aggressive towards other unfamiliar gerbils. Ideally, you should pick out two gerbils that are already living together, or that are between six and eight weeks old. This will result in a much smoother transition for them to live together in the new cage you will provide. However, if one or both gerbils are over eight weeks old a Split Cage Introduction is recommended. Split cage introductions work only for two lone gerbils. Gerbils that have been separated for more than a day need to be gradually reintroduced using a split cage.
You will need a cage or tank (15-20 gallon aquarium) that can be divided into two sections. There are some commercial cages that can be purchased that are divided in two, but these can be difficult to find. To make a split cage, simply divide the cage or tank using stiff, heavy hardware cloth with small holes. Place the divider from corner to corner, so the cage is divided into two equal triangles. (This makes it more secure.) Alternatively, your hardware store may be able to make a plexiglass divider. By drilling holes in the plexiglass you will allow the scents to travel through. In either case, be sure that the divider fits tightly and is secure. Gerbils will try to crawl under, over, or around the divider to get to the gerbil on the other side. Also, test that the cover of the cage fits snugly. Monitor the gerbils carefully after placing them in the divided cage until you are convinced that your split cage is secure.
Scent is important to gerbils just as it is to other animals, such as cats. When one animal gets accustomed to the scent of the other, they are less likely to become aggressive. For cats, rubbing each cat with the same towel will transfer scent from one to the other. When using the split cage method for gerbils, we can transfer their scents to each other by carefully switching the gerbils to opposite sides of the cage four to five times a day. After a week of these daily transfers, remove the divider. Have heavy gloves handy and be prepared to separate the gerbils if a fight should occur. You will need to watch them carefully for at least five to six hours, maybe longer. (Removing the divider is best done on a day when you will be available to monitor them closely.) Do not leave them alone together if you can not monitor them. If you need to leave, replace the divider. Once they are grooming each other and sleeping together in the same nest, you can feel confident they have made the transition well, and can live peacefully together.