In the wild gerbils form small family units. They are social creatures and hug, clean, run after, and tussle with one another. As is the case with other communal animals like wolves, there is a principal pair of gerbils that reproduce while the older progeny look after the young. As the pups reach puberty and consequently maturity, they leave their community to form another social group. Even in confinement, gerbils prefer to be in groups. However, it is entirely at the owner’s discretion to determine the most advantageous size of such a group.
The American Gerbil Society has made a set of recommendations you can see below:
Two stranger gerbils should be introduced to each other only through the split cage method (as described below). Generally speaking, young gerbils, sexually developed pairs with a mature male and young gerbils set up groups most easily. It is advisable not to keep more than two adult females together. Although some breeders have managed to breed successfully with seven male gerbils together, it is better to keep no more than four males together in one place. Never raise more than one female gerbil in a single cage. When a second litter comes along, remove all but about 1-3 gerbil pups to prevent overcrowding.
Gerbils are extremely defensive creatures and hence are somewhat violent towards gerbils they don’t know. It’s best to choose two gerbils that are already living together and are aged between six to eight weeks. This will lead to a smoother process when they move to a new cage. If one or both the gerbils are over eight weeks old, a Split Cage is the best possible solution. The Split Cage system works well for two isolated gerbils. Gerbils that have been kept separated for more than one day can be slowly reintroduced to each other through the Split Cage set-up.
Split Cage Introduction Method
A cage or tank of approximately 15-20 gallon capacity that can easily be divided into two parts is necessary. There are some two-chambered ready-made cages available on the market but these are hard to find.
To make a Split Cage, simply partition the tank or cage using stiff, heavy hardware cloth with small pores. Put the separator diagonally so that the tank is divided into two identical triangles. This kind of division makes the cage more spacious and secure for each of the gerbils.
On the other hand, you might be able to construct a Plexiglas dividing wall. Drill holes in the Plexiglas to allow the scent of one gerbil to be carried over to the other through these openings. Irrespective of whether you use hardware cloth or Plexiglas, ensure that the divider fits snugly and is secure. The gerbils will attempt to creep underneath, over or around the partition to get to the gerbil in the other half of the cage. Also, check that the cover of the cage fits properly. Do not forget to observe the gerbils after placing them in the two-chambered cage until you are absolutely confident that the split cage is safe and sound.
Just like many other animals including cats, gerbils are sensitive to scent. When one animal gets used to the body scent of the other, they tend to become less hostile. In the case of cats, wiping each cat with the same towel transmits the scent from one to the other. In the case of gerbils, you can transfer the scent effectively by cautiously moving the gerbils to opposite sides of the cage four to five times per day.
After a week of these daily relocations, slowly take away the divider. Be ready with heavy gloves to part the gerbils if a brawl starts. You need to watch them carefully for at least five to six hours, and sometimes even longer. Only remove the divider when you are available to keep an eye on the animals.
Do not leave them together unless you are there to monitor them. If you need to leave suddenly, don’t forget to put the divider back before you leave. Once you see that they have begun grooming each other and are sleeping peacefully together in the same nest, you can be sure that the transition has been successful and now, they will live together in complete harmony.