Can two different sizes of rats live together?

Question
I recently went to the pet store to look at a friend for my small male rat at
home.  I fell in love with one of the medium sized rats (and the size was
definitely significantly larger than my baby at home, but they are around the
same age).  The man working at the pet store told me that they would never
be able to live together without being aggressive.  He then went on to tell me
that rats are better off living alone and not in pairs, which I know to not be
true.  So, I'm wondering if the size of the rat matters with ability to get along
with each other?

Thanks!

Abbie

Answer
Oh broooooooooother these pet store employees need to shut up or educate themselves before they flap their yaps!!!!!!!  Rats are very social creatures and they LOVE to be with other rats, male or female, it doesnt matter. The thing is, if rats are inbred severely and there are aggression issues which is NOT normal for rats, they will have problems getting along when they go through puberty but often they work it out. severely inbred rats (either sex) can also be aggressive in general, which is a problem among pet stores that buy from big breeder mills that breed feeder rats which are not bred for health or temperament. After all, they are going to meet their maker soon when they are sold to a snake owner as food so what does it matter if the rat is going to get along with other rats or be a biter or have health problems?  Pet stores will pick out the more interesting looking rats such as those with markings or unique coloring etc....and sell them as "pets" when they really just came from the same stock as the plain white furred, pink eyed rat (whom I absolutely adore the most, the white rats and the black rats appeal to me more than any other rat, although I love them all!)

That said, (I know I talk alot, sorry!) under normal circumstances, rats will get along wonderfully and in fact I have had rats that had to take valium for depression and anxiety after their cagemate died and other rats have actually gotten sick from a suppressed immune system from stress after the death of a cagemate.

As for size, it doesnt matter unless the rat is an adult and the other one is a baby. Adult rats dont always appreciate having young rats wanting to wrestle and play chase etc...but if they are the same age I would not worry.  You must introduce them to each other carefully and slowly after quarantine is finished.  Allow them to live side by side, getting  used to the other ones scent for a few days before putting them together so they are aware there is another rat around.  Let them sniff each other before even putting them down. If this is done right, they can live happily ever after.