Mongolian gerbils are tiny burrowing rodents, that live in large familial colonies in the wild. They are excellent pets, despite only starting down the path to domestication in the 1930’s. They are active, friendly, and incredibly fun to watch.
Enclosures
The most important factor when designing a gerbil habitat is to remember that they are burrowing animals. This means they need lots of depth to their enclosure that can hold bedding. It also means that anything placed into their enclosure is likely to be buried fairly quickly. They are also very avid chewers and have the ability to chew through both wood and plastic. This these factors in mind, I highly recommend that gerbils be kept in glass tanks. The are chew proof, easy to clean, and difficult for your gerbils to throw bedding out of. They also come in many sizes and are fairly common at pet stores. In general, I would consider a 40-gallon tank to be the minimum size for a pair of gerbils. However, gerbils will use absolutely all the space that you give them, so bigger is usually better.
In terms of what to put into the enclosure, the most important thing is to fill it with bedding. Gerbils love to dig and will spend most of their time designing and re-designing a tunnel system for themselves. The most common beddings to use are paper beddings or aspen shavings. Both hold tunnels well, though aspen does reduce odor a bit better than paper. You can also mix them both together, which helps tunnels hold even better. This bedding will need to be replaced periodically. I usually just switch out the bedding once it starts to have a noticeable odor (around once per month). Another option is to give the gerbils soil to burrow in, however this has very different maintenance which is outside the scope of this post (look at my posts on bioactive gerbil enclosures if this interests you).
The other necessities for a gerbil enclosure include a water source and a wheel. The trouble is that they will constantly bury these amenities if given the opportunity. One option is to put a divider of some kind in the enclosure and create a section with less bedding to place the bowl/bottle and wheel in. You will probably end up having to move bedding out of this area every couple of days as gerbils track more in, but it should keep the wheel clear. Another is to add a platform or tank topper that is at least several inches above the bedding. Personally, I like having a taller tank and adding a platform with the wheel and water on it. This option is easier to clean than a true tank topper. It also does a very good job of keeping the wheel clear, and if the gerbils do manage to get bedding up there it’s easy to sweep back off.
With water sources you have two main options, bowls or bottles. Bottles are quite loud when drank from (a big factor if the tank is in a bedroom). They are also fairly difficult for the gerbils to bury, though if the end does get buried they will become completely un-useable and also leak water into the bedding. For this reason, they should be checked regularly. Bowls have the benefit of being quiet and much easier to clean. However, they need to be on a platform or somehow separated from the bedding, otherwise they will be filled up with bedding quickly. You will want to use a gerbil sized bowl, not one large enough that your critters might fall in and douse themselves. I have personally used both bottles and bowls. I prefer bowls for situations where noise is an issue and bottles the rest of the time. Either way I highly recommend putting them up on a platform to keep the bedding away.
Wheels are an excellent way to give your gerbils lots of exercise, which these hyperactive little critters will appreciate. As mentioned before they’ll need to be behind a divider or on a platform to protect them from being filled with bedding. For most gerbils you will need a 10-inch diameter wheel or larger. Make sure that when the critters are running they are able to hold their back and tail straight. If it is curved that means the wheel is too small and can lead to back problems over time. This will also cause your gerbils to use the wheel less and less. For safety, you will also want to look at the wheel and make sure there are no gaps that a tail could get stuck in and no hole/wire mesh that could trap toes. The material of the wheel is also relevant. Many gerbils love chewing plastic. Plastic wheels, especially softer plastic, will often very quickly get chewed to pieces. Metal is immune to this, but can be very loud. My personal favorite is wood. It can take quite a bit of chewing before breaking down (though my gerbils don’t seem particularly interested in chewing it), plus these wheels are basically silent. Whatever wheel you chose, the best part will be seeing all the crazy antics gerbils tend to get up to on it.
Food
In the wild gerbils are native to arid grasslands with the bulk of their diet being dried seeds mixed with the occasional insect or fresh plant. Luckily that is very simple to mimic with a commercial diet and there are many options on the market. There are a few factors I look at when buying my gerbils’ food. The first is macronutrients. This is basically the amount of fat, protein, and carbohydrates in the food. It should always be on the nutrition label. For an adult gerbil you are looking for 16-24% protein, and between 2-5% fat. Youngsters will likely need on the higher end of the protein spectrum while they are still growing. If there aren’t any gerbil specific foods available in your area, it can be possible to look for a hamster or rat feed that has the same nutrient profile. On average gerbils eat between 4-7 grams per day (or about 1/2 teaspoon). I recommend offering about that amount and then adjusting up or down based on how much your gerbils actually eat. Remember that gerbils will occasionally create food stashes, so if extra food disappears on one day and then very little the next that is perfectly normal. Gerbils also really enjoy variety, so I usually steer clear of food made entirely of identical pellets. It can however be nice to add pellets to a seed mix if you are worried the mix is too low in protein. Though you may need to do some math to make sure the protein ratio is right.
Enrichment
Now for the fun part. Gerbils aren’t really nocturnal or diurnal, instead they alternate several hours of sleep with several hours of wild frenetic energy. During these periods of wild energy, it’s important to give them plenty of things to do. Plus it’s incredibly fun to watch them work on their little projects and do all their natural behaviors.
The best option is to give them building materials. Hay, paper towel, dried corn husks, tissue paper, things they can shred up and use to strengthen their tunnels or pad their nests. I would suggest avoiding fabrics or cotton fluff since the threads can wrap around toes, but most paper or natural products can work nicely. Gerbils will actually take hay and other plant materials, shred them into thin strips and then adhere them to the insides of their tunnels with saliva to strengthen them. They will also take softer paper and use it to build nests to sleep in. They also really enjoy cardboard, particularly toilet paper tubes. These will also be shredded and used in the tunnel building effort. Though my girls have also pulled a few whole down into tunnels and just used the tube as part of the tunnel. Some pet stores also offer straw/hay mats or other shredder toys, which gerbils will be equally happy to pull apart for building materials. It’s incredibly fun watching gerbils complete their little building projects.
Another enrichment option is to scatter feed. Simply take some of the gerbils’ dinner, sunflower seeds, or another treat and sprinkle it over the enclosure. Then leave the gerbils to scamper around and find their food. Gerbils still have wild food gathering instincts, so it can be fun to let them use those to track down some tasty treats.
Finally you can try giving some puzzle toys or food that takes effort to get into. Peanuts or sunflower seeds still in the shell can give gerbils a challenge. Millet or oat sprigs can make your gerbils forage. Other treats like dried apples or bananas can be wrapped in paper or cardboard tubes that need to be peeled off (I usually choose strong smelling food for this). Not all gerbils are super food motivated, but most seem to enjoy the challenge.
Handling
Gerbils are not the easiest pets to handle. They are small, active, and fast. This means a lot of care needs to be taken to keep them from falling or escaping during handling. Luckily most gerbils that have good experiences with people lack fear of us despite the size difference. Often you can simply put a hand in the enclosure and wait for the gerbil to climb on. Once the gerbil is on, it can be good to create a “treadmill” of sorts. Letting the gerbil run across one hand then adding the other hand in front repeatedly so that they can keep walking.
If you are nervous about accidently dropping the gerbil, one option is to pick them up using a box or tube. Simply get a box or tube, set it into the enclosure, and either shoo the gerbil in or pop a treat inside to encourage them. Then you can cover the opening of the box/tube and simply pick it up. This can give a simple contained way to move the gerbils for cage cleanings. It can also be a good way to get the gerbil out if they’re not currently inclined to climb onto your hand, but you’d like to work on handling them.
Social Life
In the wild, gerbils live in large communal burrows and are very social. As a result when getting pet gerbils it is very important to get at least a pair, as they don’t do well in isolation. This does add the minor complication or needing to make absolutely certain that your pair of gerbils are of the same sex, lest they create many more gerbils. Male gerbils have a larger distance between their anus and their genital opening than females. In addition, once they reach maturity they’ll have visible testicles. They aren’t too difficult to tell apart, but it is something that needs to be checked before taking your gerbils home.
If you come into possession of a lonely single gerbil or are wanting to expand your colony, some work will have to be done to introduce new members to the group. Suddenly throwing new roommates into an enclosure without an adjustment period doesn’t usually go well. I personally like using the split cage method, which Springs Gerbils has an excellent explanation of here, to get your gerbils all comfortable with each other.
Sources
Little Critters Grooming 