Introducing New Rats to Your Colony You absolutely can not just throw two strange rats together. The resulting consequences could be disastrous, even resulting in the death of one of your rats. An introduction procedure needs to be followed closely in all instances of putting new rats together for their meeting to go smoothly. To save you from having to go through this process, we have recommended earlier on that you buy two rats together at the same time, from the same place, and from the same enclosure. It simplifies things greatly and you can skip all this! However, sometimes things don't work out how we would like, or you might have already owned a single rat for a while before learning that you should really have two, or you might have just lost a rat and need to get the survivor a friend. Note: Read "The Pecking Order" within this Guidebook to further understand what is going on during the introduction process. Choosing The Right Rats to Pair Up... The easiest rats to introduce together are youngsters with youngsters. The hardest rats to introduce together are intact adult males with intact adult males. The reason we recommend introducing in "two" or more rats, is that this way they have each other to rely on while entering into a new situation, and they can depend on each other for support, and it will give the established rats more than one target to pick on and dominate. Also, with youngsters they are brimming with energy, so a lone youngster can drive an older rat(s) crazy with wanting to play all the time. By getting two youngsters, they have each other to play with. (Although this is not an issue if the rat(s) your introducing them to is also young. In this situation, it is perfectly fine to add just one youngster.) If you are replacing your rat's lost friend with younger rats, it is also a good idea to add two rats instead of one, because when your other adult finally passes on, you will be left with two young, bonded, rats together, and then you will not have to worry about introducing yet another new rat, to make the number two again. So now you have read this and you are a guardian of a lonely rat, and you want to correct this situation and provide them with a rat friend. What should you do? Just reference the chart below. If You Have... - Then The Easiest to Introduce is... IMPORTANT READ! if the decision is made to introduce males and females together, either all the females or all the males involved need to be fixed first. Otherwise you will end up with lots of babies! (See "Should I Spay/Neuter my Rat?" located in this Guidebook to learn more about this subject.) One or more female youngsters - One or more youngsters. (Either sex will be just as easy to introduce.) One or more adult females - Two or more rats of any age. (Males would be slightly easier to introduce than females.) One or more elderly females - Two or more rats of any age. (Males would be slightly easier to introduce than females.) One or more male youngsters - One or more youngsters. (Either sex will be just as easy to introduce.) One or more adult males - Two or more youngsters at least six weeks old. (Females would be much easier to introduce than males.) One or more elderly males - Two or more youngsters at least six weeks old. (Females would be much easier to introduce than males.) Basically when it comes to Males, young rats between 6-8 weeks of age is what is recommended to try and introduce. Males don't seem to see babies as a threat and will usually accept them more easily than older males. Females will tend to pick on babies just as much as they would older rats, so it doesn't matter what aged rat you introduce to them, but females are a lot less territorial than males and in general are much easier to introduce rats to if done properly. Note: You can attempt to introduce any age, sex and number of rats to any age, sex and number of rats, provided you don't mix intact sexes together. That will get you LOTS of babies, so make sure you fix all the rats of one sex first before introducing it to the other. We ourselves and many people we know have successfully introduced adult intact males to adult intact males. However, we do need to mention that there are cases where no matter what you do, some rats won't get along with each other. If this is the case, then you need to house these rats separately for the rest of their lives. Again, intact adult males are the ones most likely to give you problems in this respect. If you've tried everything and your male still won't accept a newcomer, neutering him might help. The Introduction Process... Step One Quarantine, Quarantine, Quarantine! Any new rats you adopt should be quarantined first. This is to prevent the spread of possible illnesses to your healthy established rat(s). Ratty Illnesses can travel on your skin, on your clothes, and through the air circulation. Due to the fact that illness can be transferred by touch and even through the air, you need to quarantine your new rat(s) in a separate building away from your established rat(s), and you need to ALWAYS wash up and change clothes after handling your new rat(s) if you are going to handle your established rats again. If you have no place to keep your new rat(s) except in your own home, then you need to do your best to keep the new rat(s) as far away from your established rat(s) as you can. Put them in opposite ends of the house, on a different level of the house if possible, and you need to ALWAYS wash up and change clothes after handling your new rat(s) if you are going to handle your established rats again. The quarantine should be done for at least three weeks to a month, although some say even up to three months. If you spot any signs of sickness, you need to identify what your new rat(s) is ill with and fully treat them before any introductions take place. Step Two Once you've had a chance to make sure that your new rat(s) is healthy, you can start the introduction process. The key element that is involved in doing a successful intro, is that it be on neutral ground. This means a place where neither rat has been before (or that they have only been to once or twice before long ago.) Rats are very territorial and instinctually defend their territory against intruding strangers, trying to drive them away or even kill them. Introducing a new rat(s) into your rats' existing territory would be disastrous. Any where that you let your established rat(s) frequent, they will consider to be their territory, for example their cage and play area. However, if you put two rats into a neutral territory that neither one has ever been in before, neither rat will feel a need to defend anything. This gives them a chance to accept each other and become friends. We use two neutral areas for our introduction process. If rats are going to have a violent reaction to a newcomer, it will usually happen right away, so first we do an initial hour to hour and a half introduction on neutral open ground. That way if violence breaks out, it is easy to separate the fighting rats. If the neutral open ground goes successfully, we then move the rats into a small neutral cage. This allows time for the rats to bond with one another. So first find some neutral open ground that you can use for the initial intro, the stranger it is to your rats the better. You could use a bath tub, a bed, a table, etc... For our example, we will use the bath tub. Spread some Rice Krispie treats around in the tub. This will serve as a good distraction. Note: The afternoon is the best time to do this because your rats will all be sleepy and less active at this time. Put the new rat(s) in the tub first and let them check it out so that they have the advantage. Then, after a minute or so, place your established rat(s) in the tub. If you have more then one established rat, place one in, then gauge the reaction, if that goes well, after a few minutes, place the next one in, and so on. The first thing you should witness, is the rats sniffing each other all over, especially in the butt. Then you may see some dominance displays. This is all normal and fine. If you see ANY signs of anger displays, pull the new rat(s) out immediately! If they start to have a violent fight before you can get to them, do not break it up using your bare hands. Have a towel handy to use as an aid to separate them so that you do not get accidentally bit. It can be very hard to tell if an erupting fight between an established rat and a newcomer is just going to be a mild dominance scuffle or a truly violent bloody fight. Violent fights are usually just that, they are much more violent with rats screaming and blood being drawn. Dominance scuffles are much less intense and over quickly. Again your best bet is to look for anger displays and stop the introduction if you see any. (You can find descriptions of what dominance behavior and angry behavior looks like in this Guidebook under "Ratty Language and Behavior" to better gauge if you should immediately remove the new rat or not.) Note: Have a squirt bottle on hand and if one of your established rats gets a little to aggressive with one of your new rats give the established rat a squirt or two until they quit. If the initial intro turns sour, you now need to go back a step and try and stop the anger reaction by letting the rats familiarize themselves with each other in a safer manner. If it is not already, place the cage your new rat(s) is being kept in next to your established rat's cage, but make sure there is an inch or two gap between the two cages so that the rats can't pull each other in through the bars. You don't want fingers to get bitten off. With the two cages next to each other, they will be able to sniff each other and visually interact with each other, without the hazard of physical contact. In addition to putting the cages next to each other, switch the rats out into each other's cages each night, swapping back and forth, so that the rats can explore each other's habitats (without letting the rats have physical contact with each other of course.) This will allow your established rat(s) to become saturated with the new rats' smells, hopefully helping your established rat(s) to become more comfortable with the idea of having the new rat(s) around. Do this for about a week. Now try the initial intro again, but this time in a new and even stranger place. If you have a play pen you could do it outside, or even better, take the rats to a completely new house and do it there. Note: Another thing that can sometimes help with introductions is if you dab vanilla extract on all the rats' noses and genital areas to cover their ability to smell each other. You can repeat this process over and over using new places. It's hard to say when you should give it up and call it quits. I know someone who kept up with it for five months and finally reached success. You have to follow your gut. If the rats really seem to hate each other, and haven't shown the slightest bit of acceptance in several tries, it might be time to throw in the towel and give up on the idea of introducing them. If and when the initial intro goes well and you can manage to have all the rats together on the neutral ground for an hour to an hour and a half with no signs of anger, violence, or major dominance displays you can then move on to step three. Step Three Have a smaller cage set up with food and water ready on hand. This cage needs to be new or mostly new to both sets of rats, something they either haven't been in at all or maybe have been in once or twice a long time before. It's imperative that the cage be new and unfamiliar to all rats keeping it neutral to prevent fighting. We use our hospital cage also as an introduction cage and it works really well because the rats are barely ever in there. Do not put anything in the cage other than their food and water. If you put a tube or house or other item they can hide in, the rats will fight over who gets to be in it. You don't want to create fights. If the cage is empty, they have nothing to fight over. It is a good idea to spread some treats around the cage though. The reason we use a neutral cage that is small is because it forces all the rats to be in close contact with each other forcing them into a situation where they have no choice but to bond with one another, and if the cage is a neutral one, there shouldn't be any desire to fight over territory. This is a good cage size to use for introductions. A slightly smaller cage could work as well, as long as there is enough room for the rats, food, and water. Take the new rat(s) directly from the neutral open ground and plop them into the small neutral cage, and then put the established rat(s) into the small neutral cage with them. It's good to have the neutral cage in a different room other than where their regular cage is kept, to help with keeping everything new and neutral. Keep them in there all together for a minimum of at least 12 hours, although for trickier introductions I've kept my rats in the neutral cage for up to 5 days. The longer they stay in there the closer they will bond with one another. Be sure to closely observe the rats for at least the first 8 hours. Keep the cage with you during the day and put it next to your bed as you sleep. Note: Have a squirt bottle on hand and if one of your established rats gets a little to aggressive with one of your new rats give the established rat a squirt or two until they quit. If you see any signs of anger or any violence, separate the rats immediately and move back to step two. The reason you need to keep the rats in the small neutral cage for so long is because you want the rats to really be good and bonded with each other before moving on to the next step. Once the rats have successfully stayed in the small neutral cage for a long period of time, you can move on to step four. Step Four This forth step involves putting all the rats together in your established rats' most sacred territory, their cage. This is why you wanted them bonding for 10-18 hours first. Completely clean out your established rat's cage. Scrub absolutely everything with disinfectant, including the cage itself! You don't want any remaining odors. Put in fresh litter and rearrange the cage so that it looks different. Place treats around the cage for distraction. Put the new rat(s) in the cage first directly from the small neutral cage. Let them explore the whole thing for a few minutes and become comfortable. Then place your established rat(s) into the cage directly from the small neutral cage. If you haven't before, you are now probably going to see signs of dominance behavior. Your rats will have a need to establish a new pecking order. (See "The Pecking Order" within this Guidebook for more information.) Expect the new rat(s) to possibly be picked on a lot, with much chasing, pinning, and squeaking. It is important that you let them work this through, though, for as long as it takes. It could take a day, it could take months. Eventually they will become fast friends. However, if you see any signs of anger or violence you need to pull the new rat(s) out immediately and go back to step two. It is not unusual for your new rats to receive minor scratches and maybe some tiny bite wounds. This is not a reason to be alarmed or stop the introduction, but if you find any more serious injuries, you will need to go back to step two. Be sure to watch your rats very closely for the first 2-3 days. Try to check on them every hour during the day, and as often as you can throughout the night. If there are no bad injuries within this time, they should be safe to live together permanently. You will also want to make sure that every rat is getting food and water. Sometimes established rat(s) will keep new rat(s) from getting to the food dish and water bottle. You can try adding a second temporary water bottle, and spreading their rat blocks around the cage, so that the new rats will have better access to them. Confine your newly formed colony of rats to their cage for the first 2-3 days. You want to give them time to find a semblance of order before taking rats out to play. After 2-3 days it is safe to introduce the new colony to their regular play area.