Why you should always have 2 gerbils
Do Gerbils need anti-depressants?
Gerbils, unlike many of their cousins need the social interaction of other gerbils in order to live. If a solo gerbil is left alone in the cage it becomes depressed and will die. Introducing new gerbils to an established cage can create territory problems, so getting at least two in the beginning will keep them alive, happy, and friendly. Besides you can only run on a wheel so long before it gets boring.
Depression and Loneliness
Gerbils are a lot like humans because they do not cope well being by themselves. The gerbil will display very typical depression behaviors such as listlessness, reduced appetite, and isolation. They can be snapped out it with love and attention from their owner, but this will also take some time. You can ask your vet if it would be appropriate at this time to introduce another gerbil and how.
Shorter Life Span
Now, I am not saying your gerbil will commit suicide, but it is a proven fact that a depressed lonely gerbil does not live very long. The typical life span of a healthy gerbil is 2-4 years, however many lonely gerbils do not last the first year. Nothing is worse than having to bury a gerbil just because they were lonely.
Age does make a difference
If you are planning on introducing another gerbil to your lonely gerbil it is recommended they be 4-6 week old at the most. If they are any older, it will be almost impossible for them to grow accustomed to each other because they become fixated on their group's odor. All we want in the end is for everyone to be happy and healthy anyway.
Hey Bud this is my Turf
Gerbils are very territorial, and can become aggressive with others they do not know. When introducing gerbils to one another it is best to bring them to a neutral territory so that neither one is dominant of the space. Then once they have gotten to know each other a bit more you can blend the two cages together.
To avoid all of these negative reactions, it is really best to buy two or more gerbils from the same family at the same time. They will be happy with more of their family, and they will have others to play with. Gerbils also tend to play more nicely with members of their own family, just like humans.