It used to be common to keep only one rat as a pet, but this was before more information was known on exactly how social rats are. In this case, quantity most definitely has an effect on quality of rats, and it is essential that you have at least two rats.
ALSO SEE: Can Rats and Mice Live together?
How Many Rats Should I Get?
Any rat owner or reputable breeder will tell you that you need at least two or more (same gender) for them to be happy and healthy.
Lone rats (no matter how much attention you give them) very frequently end up being antisocial, timid, depressed, or even aggressive. Rats separated from a social group too early in life have been found to exhibit symptoms similar to that of schizophrenia.
Purchasing or adopting a single rat should never be a consideration, and if you are unwilling to provide the minimum care needed for rats (this includes having two, rather than a single rat), then I recommend you rethink your choice of pet.
If you are opposed to taking care of a minimum of two rats, I suggest a hamster, or a male mouse, which are best kept singly.
If you’re afraid that one wont be as friendly because he has a buddy, there is no need. They are social animals, and will only be more friendly with you if they have a buddy. A companion adds a whole different element to your rats.
READ MORE: African Soft Fur Rats Care
They will be more confident, fun to interact with and watch, as well as have better mental and physical health (which results in lower vet costs in the long run). Really, one extra rat hardly makes any difference as far as care is concerned and it is best to think of two rats as a single unit.
Quarantine IS Important!
I must stress the importance of quarantine. As rats are already prone to respiratory problems, it is very easy to carry home a virus or illness to your rat on your clothing, or in your nasal passages.
Here is information on the very dangerous Sendai and SDA viruses, which are highly debilitating, and can weaken the immune system, making rats more susceptable to other health problems and even death: http://www.rmca.org/Articles/dosanddonts.htm.
To help minimize the risks of getting your rats sick, it is very important that you wait at least 2 hours after handling other rats before handling your own.
It is also suggested that you blow your nose, and brush your teeth, as you can temporarily carry dangerous viruses in your nasal passages, which can be transmitted to your rats, even though they are harmless to yourself.
When introducing new rats to old rats, it is important that you follow a MINIMUM of 2-3 weeks quarantine in a separate airspace (preferably in a detached garage with proper heating or air conditioning, or an entirely different house) before any introductions start, as vriuses such as Sendai or SDA can remain unnoticed without visible symptoms for 2 weeks, despite being contagious.
1. Observe new rat closely during quarantine for any signs of a URI (upper respiratory infection), or other health concern.
2. Place cages next to one another in the same room for 2-3 days.
3. Swap rats into each others’ respective cages WITHOUT letting them interact or meet face to face. Let them explore each others’ cages, scent mark, and take in the smells. Do this at least once a day for 2-3 days.
4. Introduce the rats in a neutral territory, where neither has access to regularly (this is commonly a bed or a bathtub).
Keep introductions short and sweet – allow time to see and sniff, then remove before any tension is able to build up. Immediately after removing the rats, give each a treat they love, and put them some place familiar and safe.
You can do this several times a day for another 2-3 days, gradually increasing the amount of time spent together.
5. Introduce the rats in an area commonly used by either rats (free range area). Again, observe, and go slowly. Follow instructions from step 4 for another 1-2 days.
6. COMPLETELY clean out the cage that they are both going to be living in. This means removing all bedding and toys, cleaning hammocks and fabric in hot water in the wash, and bleaching the cage. You want the cage to be as good as new, so that the resident rat does not associate the cage as his territory. When ‘furniture’ goes back into the cage, put it in different places than the resident rat is used to.
7. Move newly cleaned cage into a room it is not normally kept in and add rats. Observe closely and do not leave them unattended. Squeeking and screeching is normal as they figure out their hierarchy.
The rule of thumb is NO BLOOD, NO FOUL. Rats often flip a submissive rat onto it’s back and ‘power groom’ it’s belly to express dominance. The submissive rat may squeal as though he’s dying, but if there is no blood being drawn, there is no need to worry.
NOTES: Gradually increase the amount of time the rats spend in the same cage. If you feel that the rats are getting along perfectly fine, it is likely safe to leave the new rat in with the resident rat(s) overnight, however go slowly, and be patient.
You may need to try step 6 a couple of times before they are ok with each other in the same cage. Depending on your individual rats, you may be able to shorten the steps, or you may have to go a bit slower.
Remember it is always safer to go slower than to rush introductions. Rats that are rushed are going to be stressed, and can easily cause serious injury to one another.