A bit from linked Wikipedia article about Benjamin (Animal Farm) :

Benjamin is a donkey in George Orwell's novel Animal Farm. He is also the oldest of all the animals, and is alive in the last scene of the novel. He is less straightforward than most characters in the novel and a number of interpretations have been put forward.

Some interpret his character as representing the aged population of Russia, while others feel that he represents the Menshevik intelligentsia, as he is just as intelligent, if not more so, than the novel's pigs. He is very cynical about the Revolution and life in general. It has also been argued that he represents the skeptical people who believed that Communism would not help the people of Russia, but who did not criticize it fervently enough to lose their lives. He is also quite significant in that he is not quite a horse (the working peasantry) and yet definitely not a leader like the pigs, although his intellect is equal to theirs. The fact that he also has a Biblical name could also imply that he also represents the Jewish populace of Russia whose lives were not remotely improved under Joseph Stalin's leadership. In fact, when asked if he was happier post-Revolution than before the Revolution, he simply remarks, "Donkeys live a long time. None of you has ever seen a dead donkey."

He is one of the wisest animals on the farm, and is able to "read as well as any pig". However, he rarely uses his ability, because as he feels, there is nothing worth reading. He does not use his ability for others until the end of the book, when Boxer is sent off to the slaughterhouse, and on one other occasion when Clover asks him to read the public display of the Seven Commandments, as they seem to have changed (because of years of revisions by the pigs); Benjamin reveals that the Commandments now consist entirely of the message "All animals are equal, but some animals are more equal than others". Despite his age, he is never given the option of retirement. Only the pigs' betrayal of his best friend, Boxer, spurs him into (failed) action, after which Benjamin becomes more cynical than ever.

Seen from a wider perspective, Benjamin is a symbol of intelligentsia that during the times of revolution and its aftermath is very much aware about what is going on, but does nothing about it. The general (manipulated) masses are represented by the sheep, who are not aware about their misuse, but it is Benjamin who can see how the basic rules of their society are changing and does not involve himself in any way that would threaten his security. He is also one of the most commonsensical characters, understanding that the pigs are altering the Seven Commandments, and that Boxer was killed instead of peacefully dying at a hospital.

In the 1954 film, it is Benjamin who leads the other animals in a counter-revolution against Napoleon when his treatment of them finally goes too far, although the 1999 film simply features him fleeing the farm with some of the other animals when their treatment under Napoleon's regime becomes too harsh to endure any longer.

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