>>5014485Guinea pigs/cavies live longer but are less active.
While they absolutely can be, guinea pigs aren't usually very attached to you because they can't play in a similar way to what we would consider play. I even mentioned how one of mine basically just tolerated the rest of the family but absolutely adored my dad. She would freak out and hop all over the place, which is not typical guinea pig behaviour, when she heard him come home and wouldn't calm down until he picked her up so she could chew on his beard.
Guinea pigs are better for people who aren't expecting much from a pet other than cuddles and a LOT of noises. Their sounds can be either heartwarming to you or annoying. Depends on you as a person. I like their sounds. Some other folks do not.
Rats only live 1-2 years. Rarely 3. In fact, 6 is even rarer. 12 would be a preposterous number of years for a rat to live which is why they only live one or two.
While just as verbal as cavies, most sounds rats make are out of our hearing range so we can't detect the noises they make at all. As such, you have to pay more attention to their behaviour and body language to get how they're feeling.
Rats are much more active and can bond with people much more readily.
Rats can stink. They don't always, but rats have a considerably strongly odour than cavies when they do.
Guinea pigs rarely bite and never break skin. While biting is uncommon in properly cared for and socialised rats, they do it more often than cavies and are much, much more likely to break skin.
Rats can learn tricks or even simple tasks.
Rats are naturally nocturnal so while you can play/interact with them during the day and they might even acclimate to a more diurnal schedule, they will almost certainly be more active at night. Without something for them to exercise on while you're sleeping, they will get fat and die early. They also need numerous toys to entertain themselves at night. Better in pairs specifically because you're not up at night.