Interactions with Other Gerbils
Gerbils are very social animals, and it is not a good idea to keep them
singly. Pair bonded or family units of gerbils are usually quite
affectionate with each other. They will play, chasing each other
around, wrestling and boxing. They will also groom one another, sleep
in piles, and cuddle together. Your gerbils will be much happier
if kept at least in pairs (same sex unless you plan to breed, which requires
a lot more care).
However, some gerbils will fight - although this can sometimes be difficult to distinguish from the play wrestling or boxing commonly exhibited. Often, one animal will appear distressed and loud high pitched squeaks may be heard, and the activity is more intense and violent than play. The Gerbil FAQ states that gerbils who have fought severely may never be able to live together in harmony. Not unlike people, some gerbils just cannot seem to get along. This is true even for families - young gerbils in the wild are sent off to find their own territories, so family groups may begin fighting as the babies mature. If so, they need to be separated.
If you have a single gerbil, or if one of a pair dies, it can be very difficult to introduce a new gerbil, especially mature (i.e. greater than 8-10 weeks) gerbils. It is best to keep a group of similarly aged gerbils that are raised together from a young age, but if you need to introduce older gerbils, see "How to Introduce Gerbils." Often, if you have a gerbil greater than 10 weeks, it is easiest to introduce a youngster (less than 10 weeks), although older gerbils can sometimes be successfully introduced. However, sometimes certain gerbils just don't get along, so if gerbils persist in fighting it may be necessary to just keep them separated.
Thumping
This is something gerbils do when they are excited or stressed, as a
warning to other gerbils. The thumping is produced by pounding both
hind legs on the ground. Often, if one gerbil is startled and begins
thumping (described in the gerbil FAQ as a quick "da-dum, da-dum" sound),
others in the enclosure or room will also begin thumping. It varies
in loudness and tempo, depending on the urgency or meaning, but can be
quite loud considering the small creature that produces the sound!
The infectious nature of the thumping means that if some activity in the
home produces a rhythmic thumping or clicking type noise, the gerbils may
join in.
Young gerbils may do quite a bit of thumping, but often it seems that it is just a learning activity rather than a danger warning. Thumping is also an important part of the mating ritual.
Grooming
Gerbils will often groom themselves, including one another. As
well as the benefits to their coats, this is an important part of their
social interaction. They also appreciate being offered sand for taking
a dust bath (they will roll and play in the sand, which helps clean their
fur).
Noises
Gerbils make a high pitched squeak - but mainly as youngsters.
Adults usually vocalize only when playing, excited or stressed.
Chewing/Gnawing
Gerbils, like most other rodents, are avid chewers and will chew their
way through cage furnishings somewhat regularly. It is important
to provide appropriate chewing toys, like wood blocks and branches, to
allow the gerbils to indulge this natural activity.
Burrowing
In the wild, gerbils live in a complex system of tunnels and burrows,
so it is nice to allow the gerbils room to burrow in their enclosure.
A deep layer of wood shavings combined with hay will provide some room
for burrowing.
Scent Marking
Gerbils have a scent gland on their abdomen, and this is used to mark
items in their territory. Gerbils that rub their stomachs on their
cage furnishings are simple marking their territory.