Introducing Gerbils: How to split cage properly

Gerbil Introductions : Complete Split Cage Guide

Gerbils are social animals. They like having friends and need another gerbil (or two) as their tank mates to feel safe and feel loved.

But when it comes to making new friends, this mammal displays a rather ironic behavior...

Even if it is all alone and desperately needs a friend or two, a gerbil won't accept a stranger gerbil just like that. It is fiercely territorial and will fight any new gerbil placed in its tank that it doesn't identify as being from the same clan.

This behavior comes from a natural reaction that compels a gerbil to defend its territory from 'intruders'.

However, as a responsible pet owner, there will be times when you need to put these 'intruders' together...

This typically happens:

  • If you got your gerbils from different litters and they were not already living together
  • If one of your gerbil dies and you need to get a new companion for your lonely gerbil
  • If for some reason, your gerbils have been separated from each other for more than a day
  • If your gerbils have declanned. Declanning is rare and is more typical of larger groups (three or more). But there can be extremely rare scenarios when it can happen to established pairs as well.

In all these scenarios, you will need to play the matchmaker and get your gerbils to accept each other. 

But you can’t simply place both the gerbils in the same tank and call it a day... that's a recipe for disaster (or at least a recipe for injured pets)

Rather there is a method to the madness...


Few things we will cover

Before You Introduce

  • 5 things you should know of before attempting gerbil introductions
  • Why you should never introduce baby gerbils to a female gerbil?
  • What to do if you have an old female gerbil?
  • Can you introduce a new gerbil to an existing group of gerbils?
  • Do you need to quarantine your gerbil before you do the introductions? For how long?

Build your own split cage

  • Three cage configurations you can choose: Split cage, cage in cage and side by side
  • Is there a method to introduce gerbils without using split cage? Does it work? Is it recommended?
  • Literally the best step by step guide on building split cage

Actual Introductions

  • Exact introduction steps once you have a split cage
  • Signs that split cage introductions are successful
  • Signs that introductions are not successful

Gerbil introductions involve a series of easy to follow steps that you can easily do yourself at home. The most popular method is commonly called split cage though there exist other methods too (we will cover all).

But before we get into exact steps of actual introductions, there are few things you should keep in mind...

#1 - Before Introductions

Before you attempt gerbil introductions, you should be aware of few things:

  • Ages and genders matter a lot during gerbil introductions
  • It is important to Quarantine your new gerbil before you attempt introductions
  • The tank where you do introductions has to be a neutral territory 
  • Beyond age and gender, temperament of your gerbils will determine the chances of success

Ages and Genders Matter

The success of split cage (or any other gerbil introduction method) depends upon quite a few factors. But the most important factors by far are ages and genders of your gerbils.

Young gerbils who are less than 8 weeks in age are really easy to introduce to each other. They will take zero to no time and will form strong bonds very quickly.

You literally can't go wrong with babies. You can choose almost any matchup and you will be fine.

However if one or both of your gerbils are older, the situation becomes slightly more interesting...

If your adult gerbil is a male, introductions are still reasonably simple...

The easiest matchup for an adult male is a baby gerbil. The baby could be a male or a female and both will work well.

We strongly recommended to introduce two babies at once to a lonely adult male so that you do not need to repeat the process of introduction in about 2 years or thereabouts.

Introducing your adult male gerbil to another adult male is fairly easy too...

Though this matchup will take slightly more time as compared to adding baby gerbils in the mix, it is amongst ones with the highest success rates.

Introducing a female adult gerbil to a male adult gerbil is further up the difficulty ladder. It will take longer compared to matchups above but is 100% possible. Though more than success of introduction in this matchup, you should be more worried about the possibility of breeding.

Before you introduce a male to a female, step back and ask yourself - are you ready for lots and lots of baby gerbils?

However if your lonely gerbil is an adult female... have a problem at your hand...

First and foremost, DO NOT try and introduce a baby gerbil (or a pair of baby gerbils) to your adult female.

The introductions will almost never happen successfully and your female will just injure and kill the babies.

The easiest matchup for a female gerbil is typically a young male. It will take time to introduce them successfully but they will eventually bond. However do make sure that you have taken into account the possibility of them mating and you getting many many gerbil babies.

If your female is relatively young (about 1-2 years), you can try to introduce it to another young female. This is amongst the more popular matchups but is considered more difficult as compared to introducing your female to male.

If your gerbil is an older female (>2 years), the difficulty of introducing it to another gerbil goes up significantly.

Older females don't accept other gerbils that easily and your introductions will take a long time. Your best bet, in this case, is to try a matchup with an adult male. Females typically don’t produce babies after they are two years of age, so this is a relatively safe choice from the breeding perspective as well.

Your other option is to introduce your pet to a female of similar age and size though this matchup is hard and sometimes may not succeed at all.

Existing Gerbil

New Gerbil

Difficulty Scale

Baby Gerbil

Baby Gerbil


Adult Male

Baby Gerbil (or two)

Very Easy

Adult Male

Adult Male


Adult Male

Adult Female


Adult Female

Adult Male


Adult Female

Adult Female

Somewhat Difficult

Adult Female

Baby Gerbils


Existing Group (2 or more)

Male or Female

Super Difficult

Also you should note that if you have a pre-established group of gerbils, it is very difficult to introduce a new gerbil to them. That's not to say that it will never happen as there have been some reports of success in the wild. However these occurences are few and far between and you should avoid this matchup.

The only exception to group rule is if you are introducing one lonely male to a group of baby gerbils.

Quarantine them first

If you have gotten a new gerbil, it may be a good idea to quarantine it first for about 2 to 3 weeks before you introduce it to your current pet.

This period will ensure that your new friend is not carrying a disease and won’t pass same over. If your quarantined pet stays healthy after 2 weeks, it is safe to proceed with gerbil introductions.

An initial quarantine should be followed even if your new gerbil seems healthy...

...It might be carrying germs that are not visible yet. Introductions are stressful times for gerbils and these invisible germs may inadvertently introduce an illness that will make your pet sick.

If you have acquired your new pet through a reputable pet store or a breeder, the risk of them carrying a disease is low. You may be tempted to skip the quarantine in such cases though I don't really recommend same (waiting for another two weeks won’t harm your plans, will it?)

Always do the introductions in a neutral territory

Gerbils are territorial. A lone gerbil will view its cage as something it owns and needs to defend vigorously against other gerbils.

For this reason, it is recommended to introduce gerbils in a neutral territory. This is most easily achieved by doing gerbil introductions in a cage that doesn’t belong to either gerbil.

If you do not have a spare cage and do not want to buy a new one for these introductions, you will need to make your existing cage a neutral territory.

To do this, take your old gerbil out and clean their cage thoroughly to remove any smell and scent marks that may exist. Change the litter and bedding and start fresh (don't put old bedding back). This will remove any scents and should mark the cage as a neutral territory.

Success depends upon their temperaments

Successful acceptance of another gerbil to some extent depends upon temperaments of your pets.

There will be some gerbils who will never accept strangers regardless of gender and age matchups. And there will be others who will find friends pretty quickly even if gender and age matchup says that they are difficult to introduce.

As a responsible pet owner, always be ready for a scenario where gerbil introductions don't succeed.​..

Even if all rules are followed to T, there will be some gerbils who will never get used to newer mates. This might be because of their lonely temperaments or advancing ages.

If this situation does arise, you may need to keep your gerbils separate forever. You will have to provide a lot of playtime and exercise opportunities to both your gerbils in this case.

Are you ready for this? And do you have plans to handle a non-successful introduction?

If yes, jump ahead to the next section that details the actual process of gerbil introductions...​

#2 - Build a Split Cage

Gerbils identify each other by scent and at its very essence, introducing gerbils is just getting them used to each others scent.

This is most easily done by placing gerbils in their cages such that they can see and smell but can't injure each other.

This can be achieved in a variety of cage configurations though the most often used ways are: Split cage, Side by side cage and cage in cage

Split Cage

In split cage method, the original cage is split into two and gerbils are kept in one part each.

This is by far the most often used  and the most successful mechanism to introduce two new gerbils, regardless of matchup you chose in previous section.

Side by side Cages

In this approach, two wire cages are kept side by side with their walls touching each other. Effectively the two gerbils are in separate cages but because of adjacent walls, they can smell and interact with one another.

This method doesn't work if either of your cages is a glass tank or is made of plastic.​

Cage in Cage

Cage in cage method involves placing a smaller cage inside a larger one. The inner cage is made of wire mesh while the outer cage can be made of glass or any other suitable material.

Amongst these, split cage is the most popular method for gerbil introductions. But other cage methods work similarly and involve exact same principles as split cage.

However you don't always need to separate your gerbils.​..

Doing gerbil introductions without using a split cage 

Some owners have introduced gerbils by following what is called a 'neutral territory' method.

This is nothing but taking both your gerbils to let’s say a bathtub (without water, gerbils can sink) and letting them play under supervision.

In theory, this will allow your gerbils to get used to each other's scent in what's a netural territory and because they are under supervision, you can stop a fight before it happens.

Neutral territory method only works in really easy cases (mostly when you are introducing babies to each other) and it’s not really a recommended method.

We strongly recommend split cage method, both for its suitability to a wide spetrum of cases as well as because of its much higher chances of success.

Let's get into more details...

Split cage method

As the name indicates, split cage involves dividing the wire cage, tank or gerbilarium in two parts.

This is most commonly achieved by using a wire mesh or a plexiglass (with holes drilled into it) as a divider. The divider should be secured, either with a masking tape or through other means.

There are two possible split-cage configurations: rectangle configuration and triangle configuration

In rectangle configuration, the separator is parallel to cage walls and divides the cage in two rectangles (or squares).

Rectangle Split Cage

A well constructed rectangle split cage

In triangle configuration, the separator is placed diagonally around the corners. As the name suggests, this divides the cage into two triangles.

An example of triangle split cage

Amongst two configurations, triangle formation is considered to be more secure. During introduction phase, gerbils will push their weight onto divider as they try and get onto other side and a triangle formation has lesser chances of giving way under their weight.

If you build it right, either configuration works​ and choosing one over other is matter of personal preference.

Let's now look at how to go about building the split cage​...

Step by Step guide for split cage type 1 (10 steps to construct a solid split cage)

Things you will need:

  • A new or thoroughly cleaned up tank, preferably around 10-20 gallons
  • A metal wire mesh/hardware cloth (1/4 inch is recommended, 1/2 inch works too) - can be bought from any hardware store
  • Aquarium sealant/glue
  • About 12 pieces of Wooden/Aluminium channels (optional but highly recommended)
  • Masking tape (Optional but highly recommended)
  • Wire cutter, saw, ruler/measuring tape and a pencil

With supplies secured, here are detailed steps...

​Step 1 : Measure Dimensions of your tank

Choose which way you want to go - triangle or rectangle...

Use the measuring tape and measure following:

  • Width of your gerbil tank. Measure the inside (not outside)
  • Diagonal length (only in case you chose triangle configuration)
  • Depth of tank
Step 2 : Cut your channels to exact measurements

​At this stage you should have exact measurements of your gerbil tank. Simply pick up the saw and cut your channels to exact lengths as per following schedule:

  • 4 channels that are same width as that of your tank (or same as diagonal length in case of triangle configuration)
  • 8 channels that are same length as depth of your tank
Wooden channels for split tank

Cut channels to exact measurements

Try out the fit. Demo place your channels in your tank. Take help or use duct tape as needed. Saw off any additional lengths in case channels are longer than needed. The best fit will mean that channels sit flush with your tank without any gap.

Many gerbil tanks have a small plastic edge on top. In such cases, cut your channels about 1/2 inch lesser than actual width so that they sit flush with the tank walls. Alternatively you can break bits of plastic edge where channels should sit.

Step 3​ : Stick channels to the tank and let it dry

Once you have confirmed the fit, place 4 channels at bottom of your gerbil tank. Use glue or aquarium sealant to stick these channels to bottom of tank.

Similarly, use an aquarium sealant or glue to stick other 8 channels to walls of your aquarium.​

Channels should be stuck securely to the gerbil tank

Let it dry for about 2 days (minimum 24 hours) to ensure these channels are secure and won't give way under moderate force. You can use masking tape to secure channels in place during these days.

Step 4 : Cut wire mesh to measurements taken earlier

Take wire mesh/hardware cloth and use clippers to cut it as per measurements you took earlier.

  • Height of wire mesh = Depth of your tank
  • Length of wire mesh = Width of your tank (or diagonal length in case of triangle configuration)

Err on side of cutting this mesh slightly larger (1/2 inch) than what you measured originally

Step 5 : Slide it in
wire mesh for split cage

Wire mesh should fit snugly and without bow

Slide the wire mesh inside your channels.

Check if hardware mesh fits well. If it bows or bends, use the clipper or cutter to trim it further...

Ideally, the mesh should be straight without any bends and should fit snugly. Essentially it should feel secure under moderate force.

Also make sure that height of your mesh is such that it doesn’t leave much gap on top once you have put the lid on the tank. This is important as gerbils may try to jump over the divider.

If the everything looks good, create another one of these meshes with exact same measurements and slide that inside the other channel.

This configuration will result in a double mesh divider which I recommended strongly. If you are inclined towards using a single mesh divider, make sure that holes in mesh are not big enough for gerbils to put their snouts through as if they manage to do so, they can potentially bite each other.

Step 6 : Trim and sand off any sharp edges

In case you see any sharp edge with your wire mesh, trim and sand them it off. Alternatively you can put glue blobs to cover them.

These sharp edges can hurt gerbils and it is not recommended to leave them as is.

Step 7 : Use glue or masking tape to further secure wire mesh (optional)

In case the mesh doesn't feel secure under moderate weight, feel free to use some glue or aquarium sealant to further secure it. 

However, in case you want an easily removable divider, you shouldn’t glue wire mesh to channels. Rather use a bit of masking tape

Step 8 : Don't forget the bottom

Don’t forget to check for gaps at the bottom of the tank. Gerbils can squeeze and crawl under the wire mesh (and they will try to do so).

Step 9: Put fresh bedding and water bottles on both sides

Put about 2 inches of fresh unused unscented bedding and a water bottle on both sides. Make sure that no old bedding is reused and water bottles have been cleaned and are not carrying any remnant scents.

Gerbil split tanks with bedding

Always use fresh bedding for gerbil split tanks

Step 10: Put the top lid back on

Now when you put your top lid back on, there shouldn't ideally be any gap. If there is some, you will need to plug that by using some extra wire mesh.

However with gerbils just having no gaps is not enough. Being curious animals, they will want to get to other side and will try and push up the lid. To prevent this, you should use something heavy on top to firmly secure the lid.

And your gerbil tank is ready for introductions...​

Rectangle Split Cage

This is how your gerbil split tank will finally look like in rectangle configuration

gerbil split tank

Another angle

Here is another video demonstrating a split cage construction with removable dividers. She uses aluminium channels instead of wooden ones but principles stay exactly same...

How to make split cage the easier way (split cage type 2)

If you follow the steps outlined above, you will end up with a split cage that is solid, that is reusable and that will stand the test of time. It will be as good as any for almost any gerbil matchup. To think of it, the toughest part of method above is getting your channels right. And once you do so, everything else is a breeze.

But there may be scenarios where you don't want to spend time and money on carpentry stuff. And you want something quick...


... Fret not, as you can create another type of split cage that doesn't need you to deal with channels etc and is super quick to construct.

As you are not using any channels, my recommendation is that you should ideally stick with a triangle split cage configuration. The rectangle configuration is doable but is considerably less secure when you are not using channels to hold it in place.

​Steps for constructing this are pretty simple:

​Step 1 : Measure the depth and diagonal length of your tank

Step 2 : Cut the hard wire lid such that it is an inch larger than the measurements taken in earlier step

Step 3 : Bend the edges about an inch on each side. ​This is needed to ensure a snug fit. The lid should look like this

Bend the hard wire lid on edges to ensure a snug fit inside the tank

Step 4 : Place it diagonally inside your tank. Test if it fits snugly. If not, change the bend to make slight adjustments

And that's it. Your easy split cage is ready and should look something like this.

A split cage using a wire mesh and a lid

Tie the divider to bottom base

I do recommend using a glue gun or a masking tape to secure the divider. Especially since you are not using channels to hold the wire mesh in place.

Also do not forget the bottom...

Gerbils will try to squeeze through the bottom if you leave any space there.

You can either use the glue gun to stick the divider to the bottom of the tank or alternatively use another wiremesh as base (with same dimensions as tank) and tie the divider to it using a metal wire or a masking tape.

Things to remember while building a split cage

  • Gerbils shouldn't be able to jump over the divider or crawl under it or squeeze through it. Use masking tape to secure the divider if needed.
  • Gerbils can push the tank lid up and move to the other side. Make sure that you either secure the tank lid or place something heavy on top of it. You can also use masking tape to secure it
  • Similarly gerbils will try to squeeze under the divider. Don't forget the bottom and secure it well.
  • DO NOT use chicken wire or poultry netting instead of wire mesh. Gerbils will squeeze through same and get to the other side.
  • Gerbils may bite through the mesh if they find space to put their snout through. To prevent this use 1/4 inch mesh. Also it is recommended to start with a double layer of mesh initially. If things look good after a week or so, you can remove one layer
  • The tank should strictly be a neutral territory. If a separate cage is not available, clean up your existing cage thoroughly. Use new bedding and wash accessories before putting them back in

Now that you have the split tank, let's do the actual introductions...

#3 - Actual Introductions

Remove accessories from tank

You should ideally take out all toys or accessories from the tank during split cage period...

Any accessory can be scent marked and can cause your gerbils to be territorial. You will want your pets to focus on each other instead of getting distracted.

The accessories to be removed also include their food bowls as they are another accessory for gerbils to get territorial over. During introduction phase, your pets can be scatter fed (i.e you should spread their food on the bedding).

Water bottles and nesting boxes, however, should not be removed.

Gerbils need water to stay hydrated and need nesting boxes to rest and sleep. In fact, you will need two of each.

For nesting boxes, you can use simple cardboard rolls. But make sure that you put their nesting boxes close to the divider so that they have to rest and sleep close to each other.

In summary, the split cage configuration involves:

  • A secure wire mesh divider, ideally with two layers
  • A secured top lid
  • Fresh bedding and litter
  • Two water bottles
  • Two nesting boxes
  • No other toy or accessory for the period of split cage

    Swap gerbils to mix the scent

    Once you have constructed your split cage, it is time for starting introductions.

    Place your gerbils in their own portions of the cage. Monitor them carefully to ensure that your divider is secure and will hold them in. If they are pushing the divider, it should hold up and shouldn't look like that it will cave in

    Pick them up carefully after few minutes and swap their sides. Transfer a small amount of bedding to the other side as well.

    Don't ever pick gerbils up by their tails, you will injure your pets if you do so.

    Do this about 5-7 times a day.

    It is a good idea to swap them an uneven number of times during the day. This ensures that they spend their nights in different sides of the tank.

    Put them together again

    After you have followed the swapping process for about a week, look for following signs:

    • Gerbils are not shying away from each other and are staying close to the divider most of the times
    • They sleep next to divider in their nest boxes
    • They try and groom each other through the mesh
    • They lick each other through mesh (no biting)
    • There is minimum or no scent marking behavior (Scent marking behavior is when gerbils rub their bellies on various accessories)
    • There are no stress behaviors being displayed (e.g. thumping, scurrying away to a corner etc)

    If you see these signs, things are positive and you should be ready for the next step:

    • If you are using double mesh divider, remove one of them and try using a single mesh for another week. See if gerbils continue same positive behavior for some more days (essentially look for no biting behavior)
    • If you are using a single mesh divider, you should plan to remove it completely and check if your introduction has been successful

    You will need to keep a close eye on your gerbils for about 5-6 hours after removing the final divider.

    Hence you should keep following points in mind before removing it completely:

    • You should only remove the divider on the day when you are home. You will need to stay with them 100% of times on this day. Many times gerbils seem to get along well initially but a fight breaks out after few hours. These fights if not broken can be deadly. For this reason, on this day, never ever get them away from where you can see them. If you have to get away from them for any time on this day, separate them and put the divider back on [or alternatively carry them with you]
    • Have a thick glove handy before removing the divider. If a gerbil fight breaks out, you will have to break it. Gerbils get chompy while fighting and will bite anything that presents itself. A glove will prevent injuries
    • Have a small cage or another tank handy in case you need to separate the gerbils

    Once you have taken care of above, it is time for putting gerbils back together...

    Remove all accessories and nest boxes from both sides for some time. There should be nothing for them to be territorial over or hide in once put together

    Swap gerbils one last time to the other side and then finally remove the divider

    If your gerbil introduction is successful, you will see following behaviors:

    • They immediately start licking and sniffing each other
    • They start grooming each other, this typically manifests in a situation where one gerbil lays flat and lets the other one groom
    • They are cuddling and sleeping together
    • Or they mostly ignore each other initially but are otherwise relaxed.

    Do note that when the divider is first removed, it is normal for gerbils to initially ignore each other and scurry for separate corners of the tank. Keep a close eye and in most cases they will eventually come together.

    This is how a succesful gerbil introduction looks like...

    If you see them cuddling and sleeping together after about 24-48 hours, congratulations! your introductions have worked. And your beloved pets are friends now (hopefully forever)

    You can now give gerbils their toys and accessories back (do this gradually, ideally one by one). Start with something simple like a simple cardboard to chew on.

    Do make sure that none of these accessories or toys were owned by any gerbil earlier. If they were used by one of the gerbils in past, then wash and clean them thoroughly to remove any lingering smells and to make them neutral.

    Avoid cleaning their tank for next 4-5 days and allow things to settle in.

    However, things may not be this smooth all the times and you may not always see positive results.

    Watch for these problematic behaviors post removing the dividers:

    • Are there any signs of ball fight breaking out? Gerbils will roll around as a fur ball while fighting with one another. Separate them immediately before they injure each other
    • Do you see any blood or chomped fur? If yes, it is serious and separate gerbils immediately
    • Are they generally uncomfortable with each other? Signs of this may be thumping, excessive boxing and a lot of squeaking. If yes, keep a close watch and ideally separate them for some time
    • Is there rather aggressive chasing that happens where one gerbil is chasing and the other one is trying to escape? This is not a good sign [though some amount of chasing is normal during playtimes for gerbils]

    If any of above behaviors are displayed, you will need to reseparate your pets and put them back into a split cage.

    They will need to spend another week or two there before you remove the divider again. Continue swapping their sides 5-7 times a day.

    Try this for at least a week or two and remove the divider again to see if they have bonded.​

    Do note that depending on the matchup, it may take up to 3 months for a successful introduction to happen. So you will need to be patient.

    If you follow everything step by step, you will soon have a happy and active pair of gerbils, hopefully bonded for life.

    Summary : How to do gerbil introductions

    1. Choose your matchup carefully. Not all combinations work and some are easier than others
    2. Never try to introduce a gerbil to an already established group. Chances of it working are fairly low. The only exception is babies with a lone male gerbil
    3. Make sure that your split cage divider is secure. Gerbils will try to crawl under it, jump over it, squeeze around it and will push their weight on it, essentially doing everything to get to the other side. Your divider will have to withstand all of that
    4. Remove all accessories from the cage to be used
    5. Put one gerbil on each side
    6. Swap gerbils about 5-7 times a day. Also, swap them an uneven number of times during the day so that nights are spent on alternative sides
    7. Even if gerbils seem to be going nicely after 2-3 days in the split cage, wait for a week before you put them back together. Fights can break out even if they seem to be going well initially. Give them time.
    8. Look for signs of friendly behavior. If you see those, try removing the divider. Remove dividers only on the day when you can keep an eye on gerbils for next 5-6 hours
    9. If there are any signs of fighting, separate the gerbils and put the divider back on
    10. If they are grooming and cuddling with each other and are generally friendly, keep on eye on them for another 24-48 hours. If the friendship continues, they have bonded

    Let me know of your experiences and how your introductions go in comments below...

    References and Sources

    Vance Brown

    Vance is a pet lover. He is obsessed with learning everything about his pets, including but not limited to tracking their ancestory. He has been doing this for 20 years.

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