During 1950s and 1970s, Dr John Calhoun was carrying out several experiments to simulate the Utopia of humanity. It is also known as [Universe 25]. 

Eight pairs of mice bred a population which ultimately swelled to 2,200. Then, the population is ceased growing. Eventually, the mating ceased altogether and they are vanished after five years. 

However, this experiment is not reflecting the real world scenario to the humans. Humans have intelligence to resolve problems! Also, humans have dreams and goals so they have desires on exploring to the new worlds, taking new challenges, making tools, developing  communication languages and words, working as a group, and creating new technologies to achieve their goals. 

Mice are animals that they only know two things: eat and mating! That is all!