This is what I can tell you off the top of my head :)
Rats:
- you can use a cage calculator for figuring out how many rats a specific combination of dimensions will hold (I use this:
[link])
- you also have to make sure the bar spacing on the cage is small eough that they can't escape or fit their head through
- territorial wise, it depends on the rat (most rats aren't, but they will establish a pecking order)
- they live on average of 2-3 years
- you should feed them a high quality block or kibble, like Harlan Teklad or Oxbow
- they are prone to cancer and respiratory infections so you need to have a fairly large vet fund reserved for them (you should also spay/neuter to decrease the chance of reproductive organ related cancer)
- they will need to be let out of their cage daily (I let mine out for 2-3 hours a day)
- they can be litter trained poop wise, but not with peeing
- you might also want to buy hammocks, but if you're ok at sewing (or using a sewing machine) then you could just make your own (same goes for cage liners)
Some pictures of my rats: