This probably won't go down too well, I know, but I have kept rats in the past and they are superb animals; clean, intelligent and highly sociable.
I posted this earlier, but it seems germane to repost it here:
The Baboon Revolution
Life in a baboon troop can be violent and tense. Dominant males run the show, and anything that displeases or threatens them is met with aggression. Their behavior sets the tone for the rest of the baboons.
But a curious thing happened in Kenya in the 1980s. When a tourist lodge started dumping its food scraps in a pile in the bush, the delicious heap created fierce competition among the local troop’s top males. Each day, the dominant baboons gathered to battle over the leftovers—that is, until some spoiled meat infected the males with tuberculosis, killing them off in one fell swoop.
Only those baboons that never had the chance to dine at the dump (subordinate males, females, and the young) survived, and interestingly, with the bullies now gone, nobody aggressively stepped up to fill the power vacuum, as one might have expected. Instead, the troop started to become really chill. According to the New York Times, “threats, swipes, and bites” were replaced with “affection and mutual grooming.” Also, new males were able to join the troop without risking death and dismemberment, and the newbies began behaving in a more peaceful manner too. What’s more, blood tests revealed lower levels of stress hormones in the lowest-ranking baboons when compared with lowly baboons from more traditional troops. Perhaps most remarkable of all, this cultural shift continues to this day, three decades later.