Burrowing is vital for a gerbil; gerbils need a minimum of 6 inches of a substrate such as Megazorb, Ecopetbed, Carefresh and BedExcel. Sawdust is not suitable for gerbils, it may cause respiratory problems. Hay is also good for gerbils to chew, alternate layers of hay and megazorb are good since they help support the network of tunnels.
Gerbils cannot have a fully wire cage. The best environment for them is a large glass tank, which ideally can be expanded with a wire topper. The topper means you can fill the tank section solely with substrate with the wire section allowing a place for a medium sized silent spinner, hammocks and rope toys. Most importantly, gives a place for water and a dust bath where it will not become contaminated or buried.
Your gerbils tank size must be a minimum of 24" length by 12" width by 15" high plus topper for a pair of gerbils although bigger is definitely better as gerbils are extremely lively, active rodents. If you are not using a topper, than a larger tank is needed. Tanks frequently come up on freesites and second-hand. A lid can easily be made using thin wood, a layer of mesh and a staple gun. You can also make your own tank topper.
Toys and enrichment
Gerbils love to chew, so give them plenty of cardboard and wooden toys to occupy them. Chewing is very important for them, as their teeth are constantly growing and need to be worn down. Good gerbil toys are hammocks, sisal rope, wooden rope and parrot toys, wooden bridges and cotton pods.
A medium size silent spinner wheel is very useful for exercise and some gerbils also enjoy a large exercise ball. You can also freerange your gerbil as long as you have gerbil-proofed the area and have a safe way of catching them once finished.
Please see our section on Rodent Enrichment for ideas on how to keep your gerbil happy and interested.
Pet shop cages
Please be aware that there are a huge volume of cages being sold as suitable for gerbils that it would be cruel and depressing for a gerbil to live in. Pets at home do quite a few cages, labelled as gerbilariums which are just far too small. Although they are marketed as big enough for 2-3 gerbils, in reality they do not even have enough room for a single gerbil.
Similarly, any cage that has no provision for burrowing is just not suitable for a gerbil, typically a lot of hamster and mouse cages say they fit gerbils as well, but this is not the case. Rotastack in particular is not suitable for any rodent let alone something as active and in need of burrowing depth as a gerbil. See our article on Why modular systems are bad for your pet for more information.
No animal should have its habitat determined by the space available in someone's house, or by what would looking 'good' or 'fun' in the corner of your room!