"Rats are social animals, gaining much enjoyment and stimulation from each other's company. They live in large family groups in the wild, so in captivity they live a more natural life if kept in pairs or more . They are unlike the Syrian hamster, which is a naturally solitary animal, and hence is kept alone as a pet. Rats living in groups can have a lot of fun, chasing each other around, grooming each other, sleeping in a heap, playing tug-of-war with food, wrestling, sometimes scrapping, communicating, forming friendships, and generally acting like schoolchildren at playtime..."

I'm still exploring all of my pet options.