> * You are isolating them in a relatively small space with one another. Earth. > * You have uncontrolled population growth. 3rd world. > * You are using a

> * You are isolating them in a relatively small space with one another. Earth. > * You have uncontrolled population growth. 3rd world. > * You are using a species that naturally trends towards "clan wars" for territory. History. > * They are rats, and thus have nothing productive to do with their time in the absence of survival. Snapchat doesn't count as productivity.