There is so much more to creating an interesting, stimulating habitat for your gerbils beyond a tank and litter! This post outlines what you really need, what you really don't need, and what you should avoid at all costs.
What you need:1)
Waterbottle. Don't bother with a dish of water. Gerbils are more likely to kick their litter into the water and upset the bowl, rather than sip gently like proper ladies and gentlemen.
2)
Burrow. Use a coconut, an overturned, cracked ceramic pot, or a wooden hut. Avoid anything that is plastic—it WILL get gnawed. If plastic is ingested, it can cause intestinal blockages or punctures. If your litter is deep enough, you can set the burrow on the bottom of the tank and let the gerbils create tunnels down into the litter. Your gerbils will love sleeping covered, “under ground!”
3)
Things to gnaw on. Gerbils' teeth grow continually throughout their lives, so they need to gnaw to keep their teeth the correct length. The humble toilet paper tube and paper towel tube make some of the best gerbil gnaws! Gerbils also like to gnaw on wood. You can use any of the woods listed here:
www.egerbil.com/domestic6.html.
What you should get:1)
Wheel. Avoid hamster-style wheels, like this one.

The bars are difficult to run on, and since gerbils run so fast they can easily get a foot stuck, resulting in injuries like broken bones. In addition, the tail can get caught between the bar across the wheel and the supporting bar, leading to breakage or amputation. Instead, you can try the mesh metal wheel (like this one).

The potential problems with this wheel are that a gerbil can catch a toe in the mesh, leading to injury. In addition, running on the rough metal surface can eventually damage the soles of the gerbils' feet. Compared to a traditional hamster-style wheel, though, this type of wheel is much safer. You can easily get around the potential problems by wrapping the outside of the wheel with cardboard. Finally, you can select a solid wheel, like the Silent Spinner.

The downside to using this type of wheel is that it is plastic, so it has the potential to be gnawed and broken. As noted above, if plastic is ingested, it can cause intestinal blockages or punctures. In addition, if a gerbil urinates or makes a poop on the wheel, it can't fall through, so the wheel will need to be cleaned regularly.
2)
Playpen. Especially if you don't have a wheel, your gerbil will need exercise. An enclosed play area with plenty of places to hide and things to gnaw on will keep your gerbil entertained and happy. You can put sheets of paper or a towel down on the floor to protect your gerbil from any harmful chemicals or dirt (and to protect your floor from your gerbils!). If you see your gerbils chewing on the towel, however, try a different tactic. The fibers can be ingested and the strings can wrap around a limb, which is bad news (see “Fluffy Bedding” below). Finally, make sure that the walls of the playpen are tall enough to prevent a gerbil from jumping over (gerbils can get over walls that are 18'' high), and never leave your gerbil unattended in a playpen unless your are 100% certain that it is 100% secure.
3)
Plain bedding. Your gerbils will appreciate something soft and fluffy to use to line their burrow. Try plain toilet tissue or plain facial tissues. They'll shred it up themselves into clouds of fluffy whiteness!
4)
Chinchilla sand. Many gerbils like to take sand baths. The sand helps to keep their coat soft and not oily. Get chinchilla sand and use an old pie plate. Put the plate in their tank and watch as they have a blast rolling around.
What you don't need:1)
Fancy toys. Chances are high that your gerbil won't touch those brightly colored pieces of wood shaped like hamburgers and hot dogs. Save your money!
2)
Run-about balls. While there might be some gerbils out there that like the run-about ball, it seems that the majority do not. Run-about balls tend to quickly accumulate urine and feces, which isn't a pleasant environment for your gerbils (especially when they try to run, causing the urine and feces to fly everywhere!). The ball will pick up all the lint and dust on your floor, making it difficult for your gerbil to see where he is going.
What you should avoid:Just because a product has a picture of a gerbil on the package doesn't mean that it's suitable for gerbils. You should always avoid:
1)
Fluffy Bedding. Any type of fluffy bedding is completely inappropriate for gerbils. Arms, legs, and/or tails can become wrapped in the fibers, cutting off circulation and leading to loss of the limb.
2)
Rope or other fibrous playthings. This is unsafe for the same reasons as "fluffy bedding," above.
Photo Credits:Hamster wheel from
www.jupiterimages.com/popup2.aspx?navigationSubType=itemdetails&itemID=23298387Mesh wheel photo starring Bel, taken by pepandmax
Silent Spinner wheel from
www.exoticnutrition.com/SPINNER.jpg