Housemate wants a pet rat...

[otolith]

I had pet rats years ago. Charming little beasts, very friendly.

[Chris Type R]

We've had pet rats in the past and they make good pets. They have very distinct characters.

Unfortunately they don't live long, and due to attachment you can spend a disproportionate amount of cash at the vet prolonging their lives.

If they're left out to run about, they can cause chewing damage - this trait varies from rat to rat.

[Dr Mike Oxgreen]

Autopilot said:

pretty much all of them developed respiratory problems (Pasturella I think?). They get the sniffles, start making a rattling sound and need to get on the antibiotics rather quickly.

They are prone to respiratory illness, but it is exacerbated by sawdust which is a bad choice of substrate. Much of it will be softwood, which will contain resins that irritate the lungs. I always used to use a type of horse bedding that was simply cardboard cut into small squares (about an inch squared). Doesn't look as pretty or smell as nice, but its lack of smell is a good thing as far as the rats are concerned.

[Alex]

We used a particular type of cat litter.

[bexVN]

Cat litter without pine (pine is an irritant to them)

[dirkgently]

She can have the fat bd that is sat on my lawn if she likes, it`s about the size of a Dachshund and is terrifying the local cats.