i just think it's very fitting to his personality

so since I’m probably getting pet rats in a couple weeks and I’m excited for them, what if all the Pines had their own very close pet, not just Mabel with Waddles?

Dipper would, I think, do a ton of research before selecting a strange, somewhat exotic pet that fits his personality. Maybe an African Grey parrot, known to be super smart, that Dipper spends hours trying to teach intelligence puzzles and increasingly complicated phrases? Imagine Dipper using his parrot as a study aide, pretending its a person he’s teaching the content to (they say teaching something is the best way to properly learn it) and this leads to amusing situations where the parrot starts including trigonometric functions and the steps of mitosis into its everyday randomly repeated vocabulary

Stan would probably be much more “boring” by comparison, having taken pity on some stray cat or dog (grudgingly impressed by its moxie in breaking into the shack or something). The stray is missing half an ear and is clearly blind in one eye with a crooked tail, looks ugly as sin and hates everything and everyone except for Stan. They learn to tolerate family, but they will never cuddle and ask for attention from the other Pines like Waddles sometimes does. 

This is totally coloured by my recent experience, but I like the idea of Ford having a rat. Normally, rats are always better in pairs, but Ford just has the one. It makes up for this species isolation by literally always being with Ford, somewhere in his jacket or sleeve usually. Rats also only live at most to 3 years, but Ford had it out of the portal, and its still pretty spry after a couple years on the Stan o War. Stan’s convinced it’s some genetically altered specimen Ford rescued, because there’s no way Ford has a normal pet rat. Dipper thinks its a normal rat and that Ford is doing Great Science Things to prolong its life. Mabel thinks that it’s “love conquering all” and that karma really owes it to Ford anyways. The real truth is that it’s a pet rat that happens to be from a dimension where rats have a much longer lifespan and are even more intelligent