The carrier or small space method (broad use)
What is it: It either starts straight into a small confined space or starts with introductions in a small neutral space (such as the sofa or a table top) if you wish to have better visability of how things are going initially. Then moves to an empty small space which is small enough to mean the rats need to stay close together and cannot avoid each other. Cage size and furniture is increased in stages once the rats seem settled and relaxed at each step, until the rats are happy in a large space. Once introduced unless proper injuries occur the rats are not separated again. Small scale fighting is allowable, aggressive or violent fighting is interrupted where possible and separated if this fails to work
Why: A smaller space means less area for a rat to control/defend (so dominance does not need to be pushed as far). The smaller space means rats avoid each other less (so resolving hierarchy disputes quicker). A small space also means there is less room to run away (reducing the chance of injury as most introduction related injuries occur when a rat runs from a confrontation and is grabbed). The rats are allowed and encouraged to work out their hierarchy as quickly as possible to cut down on the length of time they are stressed for.
Strengths: It is an intensive form of introductions but generally works faster than any other method. It appears to work particularly well with bucks and those that are hierarchy driven. It works well in most situations (excluding those listed below) and is a good starting point.
Weaknesses: Its weaknesses are with rats that are very aggressive/territorial who may cause injury to others during introductions or where you have a particularly ill/weak rat that is being introduced to potentially active and rough rats. It may also be difficult where you have a group of rats that all actively avoid confrontation but are not ready to become friends (leading to permanent stalemate). In some cases a rat who has been on its own for some time and lost the ability to ‘speak rat’ may also struggle more, in these situations it is often necessary to adapt approaches..
You also need to be very careful in very hot weather with this method, particularly if you are using poorly ventilated spaces like enclosed carriers or show tanks. Rats (particularly adult bucks) can overheat and this can be fatal.
Hints and Tips: Make sure you scatter feed food at this stage, as it helps rats move around together and mingle. Depending on the length of time try and avoid free ranging, especially in a large area, a bit of out time in a small neutral space for a short time each day works fine in some longer introductions (where the rats are settled). Don’t add enclosed beds like igloos and cubes and avoid tubes until the rats are in their big cage and very settled. Dead ends lead to cornered rats which can lead to avoidance, excessive defensiveness or even nasty fights. If you are struggling with them in the first small space try taking the carrier/cage someone completely new smelling, such as in the car on a drive, or outside if it’s warm, or even a friend’s house. This can distract them and encourage them to bond together against the common scariness. In some cases starting in a neutral space may not work for your rats and you may be better off going straight into the carrier.
Why: A smaller space means less area for a rat to control/defend (so dominance does not need to be pushed as far). The smaller space means rats avoid each other less (so resolving hierarchy disputes quicker). A small space also means there is less room to run away (reducing the chance of injury as most introduction related injuries occur when a rat runs from a confrontation and is grabbed). The rats are allowed and encouraged to work out their hierarchy as quickly as possible to cut down on the length of time they are stressed for.
Strengths: It is an intensive form of introductions but generally works faster than any other method. It appears to work particularly well with bucks and those that are hierarchy driven. It works well in most situations (excluding those listed below) and is a good starting point.
Weaknesses: Its weaknesses are with rats that are very aggressive/territorial who may cause injury to others during introductions or where you have a particularly ill/weak rat that is being introduced to potentially active and rough rats. It may also be difficult where you have a group of rats that all actively avoid confrontation but are not ready to become friends (leading to permanent stalemate). In some cases a rat who has been on its own for some time and lost the ability to ‘speak rat’ may also struggle more, in these situations it is often necessary to adapt approaches..
You also need to be very careful in very hot weather with this method, particularly if you are using poorly ventilated spaces like enclosed carriers or show tanks. Rats (particularly adult bucks) can overheat and this can be fatal.
Hints and Tips: Make sure you scatter feed food at this stage, as it helps rats move around together and mingle. Depending on the length of time try and avoid free ranging, especially in a large area, a bit of out time in a small neutral space for a short time each day works fine in some longer introductions (where the rats are settled). Don’t add enclosed beds like igloos and cubes and avoid tubes until the rats are in their big cage and very settled. Dead ends lead to cornered rats which can lead to avoidance, excessive defensiveness or even nasty fights. If you are struggling with them in the first small space try taking the carrier/cage someone completely new smelling, such as in the car on a drive, or outside if it’s warm, or even a friend’s house. This can distract them and encourage them to bond together against the common scariness. In some cases starting in a neutral space may not work for your rats and you may be better off going straight into the carrier.
How to use it
1, Look at your options for small spaces. You ideally want a few options, that offer you the opportunity to move up in stages, or skip stages if everything is going well. The size needs to reflect your group size and the potential awkwardness of introductions. So you may be able to use a show tank or small animal style carrier for groups under around 5 rats if they are really being stubborn, but for large groups this may be too small, particularly in hot weather or with big bucks. A good rule of thumb is the minimum sized space should enable the rats to lie out and still have a little bit of free floor showing, this is a guideline rather than a straight rule though. Typically it can be useful to have the following kind of options available
You may not end up needing all of the cages, for instance it is not abnormal when introducing kittens from us to existing family members to start at stage 2 and go up to maybe 3.5 or 4. However all sizes are handy to have in, both for intros and because stages 1 and 2 make great travel carriers, 2 is a great hospital cage and 3 is a good short term stay cage (say a weekend). If you are struggling then normally someone in the wider family can lend you appropriate stage cages temporarily.
You can either have your carrier/intro cage completely clean and unfamiliar or have it smelling of the expected dominant rats, which will help them feel more secure and so calmer. However for some rats, if they see a space as 'theirs' they may be more likely to defend it, so watch the rats and judge which you think is best. Make sure that it is empty of everything except for a water bottle - or ideally two. You can scatter a little bit of food around to distract the adults but don’t put it in a bowl as this may be defended, or any cage furniture such as hammocks. Ideally cover the floor with your usual substrate or litter, rather than a towel or fleece, as this can be used to hide in.
You also want to have a water spray or towel handy. This is used where you really need to separate or distract the rats if they start really fighting. Unless you are prepared to get bitten (potentially badly) and are experienced at handling rats don’t separate a fight with your hands. The rats involved genuinely won’t realise it’s you and may lash out in fear or anger.
2, Optional step: Whether to do this depends on the situation, with rats you expect to intro easily (e.g. related kittens to adults) then this is probably unnecessary, or where you are worried about someone kicking off in a larger space it may not be a good idea. Starting intros in a small neutral area is about giving you time to read the rats a little more, which can be useful if you know what you are looking for. If you wish to do this step then take the carrier and rats into a room that the rats don’t normally free range in which has a small neutral rat safe space in it (table top, couch, bed or bath with a towel down) and add the rats to this neutral space. Where you have a strong, confident Alpha, add them and the newcomers first. Once he is settled then add the calmest rat in your group, going from those you think will be the easiest to intro, to those you think will be hardest, one rat at a time. This doesn’t overwhelm the newcomers as quickly and also with the Alpha being happy with them to start with he will often intervene if any following rat takes things too far. Guidance on what behaviour to look for is included in step 3. If you choose not to follow this step move straight to step 3
3, Take your chosen starting point to a secure area; for intros where you are not expecting it to be too stressful then introducing in their normal room is fine, for those that have the potential to be more difficult try to intro in an unfamiliar area or room (e.g. a friend’s house, a room they don’t go in often, near an open window in warm weather and so on). Typically you do not need to go all the way down to stage 1 for a straightforward introduction, however if you are concerned it is worth going through stages a step at a time. Make sure you’ve got enough time to be around the intro for at least a few hours at first and are not away for long than a working day for the next few days.
4, Add the rats to the carrier. Usually you want to add the new rats first, then one or two of your most trusted rats or all of them at once depending on how settled the group and the newcomers are. Close the cage / carrier but make sure it is done loosely so you can get in quickly if needed (e.g. when using a mini cage keep it unclipped from the base).
At first they may seem a little surprised, confused and hesitant. Then they are likely to start sniffing each other with increasing enthusiasm. At this stage it tends to go one of two ways. Either one or two rats will start to get fluffed up and huffy, or they will continue in a fairly relaxed manner. The first is a warning sign, when you see rats start to get really wound up they will fluff up there fur and start to stomp around, often lowering their heads and turning sideways on. This is them posturing and trying to look bigger and more dangerous. It is a sign that a fight may not be far away. Keep a close eye. If they start to really fight (resemble rolling balls of fluff) then either spray with the water spray or bang sharply nearby or on the cage roof. This is aimed at snapping them out of that aggressive frame of mind. This should be enough to stop the fighting, but if not it may be necessary to throw a towel over them or remove the really wound up rat. If a rat keeps on getting seriously upset and posturing (and I don’t mean pinning or grooming other rats in a low key manner, or sitting hunched and fluffed up in a corner) then try removing them (be careful doing this if they are wound up, use the towel or gloves if needed) and give them a good firm stroke down and cuddle. You are trying to help them move out of the frame of mind they are in and distract them a little. If this continues and there is a lot of fluffing and upset then try moving the rats down a stage into something smaller (if appropriate). You can also try to distract them via gently swinging the cage or carrier whilst walking around, taking them for a drive, or into somewhere that smells really weird (if it’s not too hot in spring or summer taking the cage out with you to sit in the shade can help).
If the rats stay low key, maybe sniffing intently, or maybe there is some flipping and pinning by the larger / more dominant rats (they may get a little fluffed up at this stage but watch and try not to intervene unless they really kick off). This is fine, a little disagreement or telling off is a fairly normal part of establishing a hierarchy, particularly if you’ve got young exuberant kittens with no understanding of appropriate behaviour to adults (e.g. not to bounce on them).
During this phase you may also see a lot of defensive or standoffish behaviour. This shows itself where a particular rat with get scared (usually by someone telling them off previously) and end up holding themselves in a defensive stance, usually backed into a corner standing or sitting up with its teeth bared and its paws in front. It may squeak pitifully and push away or warn away any rats getting too close. As long as the other rats are not getting fluffed up or angry at this leave them be and over time the defensive rat should start to relax as they cannot maintain that for long. Again as with aggressive behaviour distraction can help move past this more quickly.
In some occasions injurys can occur in this stage (or later in the process), however the decision whether or not to halt / pause the intro or continue should take place based off the extent of the injury and how the individuals are behaving. The most common type of injury is either a tuft of fur being pulled out (nothing to worry about) or sometimes a gash. These can look nasty as rat teeth are very sharp and can easily slit the skin so muscle shows through, or tear an ear. Despite how nasty they look they heal very quickly in rats (injuries that would floor us don’t bother them) and typically just need a quick clean (chlorohexidine containing item e.g. hibiscrub / germolene / savlon , or similar) and monitor. You will normally find them virtually closed up by the next day. They don’t need vetinery attention unless the rat is bleeding heavily and it doesn’t stop in a few minutes or it has caused something that should be inside to come out (can happen where they accidentally catch the testicular sack). Both would need urgent attention and a pause to the intros, at least for the injured party. More rarely they can sprain a limb (tends to be later stage) or rarer still you may get a rat that wants to cause damage, in which case there will be multiple wounds or more of the deep puncture wounds (these are likely to abscess). In this case definitely stop, and you may need to consider neutering the instigator. You also need to watch out for introductions aggravating existing conditions, e.g. the very old or unwell. These can be managed but if you notice a rat falling unwell or getting worse it may be worth a pause until they have improved, or following an alternative approach.
5, Once things have settled down and everyone sleeping together leave them to it for a period of time. Try to relax and breathe a bit! Stay within hearing range but maybe leave the room, as intros tend to go worse if they pick up on your stress. Try and avoid having them in your bedroom overnight, whilst this may seem a good idea lack of sleep doesn’t help you support the intro effectively and as long as the intro is not very violent at this stage (if it is you may need to separate and rethink) they are best left without your around feeling stressed about it (remember rats communicate a lot via smell, and rely on you for consistency and calmness). There may be the odd 'war' again, with squeaks and bumps when you should go back in and check them, but don’t be tempted to split them up unless it’s serious. The dominant rats will probably have to put the newcomers in their place a few more times over the next day or two before peace reigns. This stage can take an hour, or it can take a few days. Times vary a lot depending on the rats. Note: in hot weather or a particularly stubborn introduction you may want to rethink the approach a little, check out the trouble shooting section later.
6, Moving up a stage: You are looking for the rats to be relaxed around each other at this stage. Rat piles are a useful guide but if when they are awake they are still tiptoeing around each other then it may need more time. Once things have been settled in stage 1 or 2 for at least a couple hours you can think upgrading to a larger space. Start with it completely bare, apart from 2 + water sources and substrate. Transfer some of the substrate / bedding from the carrier and add the rats. This helps ensure that the new cage smells like ground they have already sorted the hierarchy out on, so helps a smooth transition. When you increase cage size it can sometimes reignite tension and squabbles (other times they don’t seem to notice and have a quick explore then go to sleep). Because of this upgrade when you can be around for an hour ish as this is the highest risk time. Don’t be afraid of moving back a step if they really are refusing to settle. As with the previous step once your past the initial squabble and tension leave the room, you will only make it more stressful.
7, Once you’ve been at this larger size for a while (again a how long is a piece of string) and the rats are again visibly relaxed around each other, try adding a single open hammock. It can also be worth (with some groups where individuals are clearly stressed from lack of exercise) adding a wheel to burn off some frustration, but as this can also be hidden behind be prepared to remove it if it causes issues. Much like last time you are looking for the rats to be visibly relaxed around each other, which is likely to be happening a lot faster. Your choice is then to gradually add more stuff, fully furnish or even upgrade. A lot will depend on how the rats are doing, a group that has barely or never kicked off at any stage may well be ready to go in a fully furnished normal cage straight away, a group that has had difficulties with every change may need much more gradual introductions of changes and scaling up with time between to settle. There isn’t a right answer, more a case of trial and error. You can go back a step, or skip steps and see how things go. Just judge it by the rats and their level of tension with each other. If your hitting a lot of issues, or this style of intros is taking weeks check out the new troubleshooting section
- Stage 1: show tank or small animal carrier with water bottle fitted e.g. Ferplast Geo XL (35.6 x 23.4 x 22.8 cm) or ferplast Aldino medium
- Stage 2: Mini cage (low roof, small footprint) e.g. pets at home hamster wire cages (Small - 25 x 30 x 47cm, Medium - 25 x 30 x 50cm orLarge - 30 x 38 x 59cm
- Stage 3: Larger low level cage, e.g. an Alska (84 x 48.5 x 44 cm) or Grosvenor (78 x 48 x 36)
- Stage 4: Full cage (note if your full cage is large and splitable you may want a 3.5 which would be half the cage)
You may not end up needing all of the cages, for instance it is not abnormal when introducing kittens from us to existing family members to start at stage 2 and go up to maybe 3.5 or 4. However all sizes are handy to have in, both for intros and because stages 1 and 2 make great travel carriers, 2 is a great hospital cage and 3 is a good short term stay cage (say a weekend). If you are struggling then normally someone in the wider family can lend you appropriate stage cages temporarily.
You can either have your carrier/intro cage completely clean and unfamiliar or have it smelling of the expected dominant rats, which will help them feel more secure and so calmer. However for some rats, if they see a space as 'theirs' they may be more likely to defend it, so watch the rats and judge which you think is best. Make sure that it is empty of everything except for a water bottle - or ideally two. You can scatter a little bit of food around to distract the adults but don’t put it in a bowl as this may be defended, or any cage furniture such as hammocks. Ideally cover the floor with your usual substrate or litter, rather than a towel or fleece, as this can be used to hide in.
You also want to have a water spray or towel handy. This is used where you really need to separate or distract the rats if they start really fighting. Unless you are prepared to get bitten (potentially badly) and are experienced at handling rats don’t separate a fight with your hands. The rats involved genuinely won’t realise it’s you and may lash out in fear or anger.
2, Optional step: Whether to do this depends on the situation, with rats you expect to intro easily (e.g. related kittens to adults) then this is probably unnecessary, or where you are worried about someone kicking off in a larger space it may not be a good idea. Starting intros in a small neutral area is about giving you time to read the rats a little more, which can be useful if you know what you are looking for. If you wish to do this step then take the carrier and rats into a room that the rats don’t normally free range in which has a small neutral rat safe space in it (table top, couch, bed or bath with a towel down) and add the rats to this neutral space. Where you have a strong, confident Alpha, add them and the newcomers first. Once he is settled then add the calmest rat in your group, going from those you think will be the easiest to intro, to those you think will be hardest, one rat at a time. This doesn’t overwhelm the newcomers as quickly and also with the Alpha being happy with them to start with he will often intervene if any following rat takes things too far. Guidance on what behaviour to look for is included in step 3. If you choose not to follow this step move straight to step 3
3, Take your chosen starting point to a secure area; for intros where you are not expecting it to be too stressful then introducing in their normal room is fine, for those that have the potential to be more difficult try to intro in an unfamiliar area or room (e.g. a friend’s house, a room they don’t go in often, near an open window in warm weather and so on). Typically you do not need to go all the way down to stage 1 for a straightforward introduction, however if you are concerned it is worth going through stages a step at a time. Make sure you’ve got enough time to be around the intro for at least a few hours at first and are not away for long than a working day for the next few days.
4, Add the rats to the carrier. Usually you want to add the new rats first, then one or two of your most trusted rats or all of them at once depending on how settled the group and the newcomers are. Close the cage / carrier but make sure it is done loosely so you can get in quickly if needed (e.g. when using a mini cage keep it unclipped from the base).
At first they may seem a little surprised, confused and hesitant. Then they are likely to start sniffing each other with increasing enthusiasm. At this stage it tends to go one of two ways. Either one or two rats will start to get fluffed up and huffy, or they will continue in a fairly relaxed manner. The first is a warning sign, when you see rats start to get really wound up they will fluff up there fur and start to stomp around, often lowering their heads and turning sideways on. This is them posturing and trying to look bigger and more dangerous. It is a sign that a fight may not be far away. Keep a close eye. If they start to really fight (resemble rolling balls of fluff) then either spray with the water spray or bang sharply nearby or on the cage roof. This is aimed at snapping them out of that aggressive frame of mind. This should be enough to stop the fighting, but if not it may be necessary to throw a towel over them or remove the really wound up rat. If a rat keeps on getting seriously upset and posturing (and I don’t mean pinning or grooming other rats in a low key manner, or sitting hunched and fluffed up in a corner) then try removing them (be careful doing this if they are wound up, use the towel or gloves if needed) and give them a good firm stroke down and cuddle. You are trying to help them move out of the frame of mind they are in and distract them a little. If this continues and there is a lot of fluffing and upset then try moving the rats down a stage into something smaller (if appropriate). You can also try to distract them via gently swinging the cage or carrier whilst walking around, taking them for a drive, or into somewhere that smells really weird (if it’s not too hot in spring or summer taking the cage out with you to sit in the shade can help).
If the rats stay low key, maybe sniffing intently, or maybe there is some flipping and pinning by the larger / more dominant rats (they may get a little fluffed up at this stage but watch and try not to intervene unless they really kick off). This is fine, a little disagreement or telling off is a fairly normal part of establishing a hierarchy, particularly if you’ve got young exuberant kittens with no understanding of appropriate behaviour to adults (e.g. not to bounce on them).
During this phase you may also see a lot of defensive or standoffish behaviour. This shows itself where a particular rat with get scared (usually by someone telling them off previously) and end up holding themselves in a defensive stance, usually backed into a corner standing or sitting up with its teeth bared and its paws in front. It may squeak pitifully and push away or warn away any rats getting too close. As long as the other rats are not getting fluffed up or angry at this leave them be and over time the defensive rat should start to relax as they cannot maintain that for long. Again as with aggressive behaviour distraction can help move past this more quickly.
In some occasions injurys can occur in this stage (or later in the process), however the decision whether or not to halt / pause the intro or continue should take place based off the extent of the injury and how the individuals are behaving. The most common type of injury is either a tuft of fur being pulled out (nothing to worry about) or sometimes a gash. These can look nasty as rat teeth are very sharp and can easily slit the skin so muscle shows through, or tear an ear. Despite how nasty they look they heal very quickly in rats (injuries that would floor us don’t bother them) and typically just need a quick clean (chlorohexidine containing item e.g. hibiscrub / germolene / savlon , or similar) and monitor. You will normally find them virtually closed up by the next day. They don’t need vetinery attention unless the rat is bleeding heavily and it doesn’t stop in a few minutes or it has caused something that should be inside to come out (can happen where they accidentally catch the testicular sack). Both would need urgent attention and a pause to the intros, at least for the injured party. More rarely they can sprain a limb (tends to be later stage) or rarer still you may get a rat that wants to cause damage, in which case there will be multiple wounds or more of the deep puncture wounds (these are likely to abscess). In this case definitely stop, and you may need to consider neutering the instigator. You also need to watch out for introductions aggravating existing conditions, e.g. the very old or unwell. These can be managed but if you notice a rat falling unwell or getting worse it may be worth a pause until they have improved, or following an alternative approach.
5, Once things have settled down and everyone sleeping together leave them to it for a period of time. Try to relax and breathe a bit! Stay within hearing range but maybe leave the room, as intros tend to go worse if they pick up on your stress. Try and avoid having them in your bedroom overnight, whilst this may seem a good idea lack of sleep doesn’t help you support the intro effectively and as long as the intro is not very violent at this stage (if it is you may need to separate and rethink) they are best left without your around feeling stressed about it (remember rats communicate a lot via smell, and rely on you for consistency and calmness). There may be the odd 'war' again, with squeaks and bumps when you should go back in and check them, but don’t be tempted to split them up unless it’s serious. The dominant rats will probably have to put the newcomers in their place a few more times over the next day or two before peace reigns. This stage can take an hour, or it can take a few days. Times vary a lot depending on the rats. Note: in hot weather or a particularly stubborn introduction you may want to rethink the approach a little, check out the trouble shooting section later.
6, Moving up a stage: You are looking for the rats to be relaxed around each other at this stage. Rat piles are a useful guide but if when they are awake they are still tiptoeing around each other then it may need more time. Once things have been settled in stage 1 or 2 for at least a couple hours you can think upgrading to a larger space. Start with it completely bare, apart from 2 + water sources and substrate. Transfer some of the substrate / bedding from the carrier and add the rats. This helps ensure that the new cage smells like ground they have already sorted the hierarchy out on, so helps a smooth transition. When you increase cage size it can sometimes reignite tension and squabbles (other times they don’t seem to notice and have a quick explore then go to sleep). Because of this upgrade when you can be around for an hour ish as this is the highest risk time. Don’t be afraid of moving back a step if they really are refusing to settle. As with the previous step once your past the initial squabble and tension leave the room, you will only make it more stressful.
7, Once you’ve been at this larger size for a while (again a how long is a piece of string) and the rats are again visibly relaxed around each other, try adding a single open hammock. It can also be worth (with some groups where individuals are clearly stressed from lack of exercise) adding a wheel to burn off some frustration, but as this can also be hidden behind be prepared to remove it if it causes issues. Much like last time you are looking for the rats to be visibly relaxed around each other, which is likely to be happening a lot faster. Your choice is then to gradually add more stuff, fully furnish or even upgrade. A lot will depend on how the rats are doing, a group that has barely or never kicked off at any stage may well be ready to go in a fully furnished normal cage straight away, a group that has had difficulties with every change may need much more gradual introductions of changes and scaling up with time between to settle. There isn’t a right answer, more a case of trial and error. You can go back a step, or skip steps and see how things go. Just judge it by the rats and their level of tension with each other. If your hitting a lot of issues, or this style of intros is taking weeks check out the new troubleshooting section