[adamanteus]

I don't see a problem with multi-species housing if, as Stefan says, the requirements are the same and the snakes are of similar size. Although personally I never do it, I couldn't really say why, I just don't. All my species and sub-species are housed separately from each other.

I don't think it's true to say Garters are very social, or even at all social. They brumate en-masse and form breeding aggregations, but then they lead solitary lives, as other snakes do.