Squealer is a fictional character, a pig, in George Orwell's Animal Farm. He plays the secondary antagonist to Napoleon, the pigs' leader. He serves as Napoleon's second-in-command and the farm's minister of propaganda, and is described in the book to be an effective and very convincing orator. In the book, he is described as merely a fat pig, but in the 1954 film, he is a pink pig, whereas in the 1999 film, he is a Tamworth pig who wears a monocle.

Throughout the novel Squealer is highly skilled at making speeches to the animals. He is also one of the leaders of the farm. Under the rule of Napoleon, Squealer does things to manipulate the animals. Squealer represents Vyacheslav Molotov who was Stalin's protégé and head of Communist propaganda.

It is also possible that Squealer represents the Soviet newspaper, Pravda. This paper was Stalin's key to propaganda in the communist times, and was very powerful to proletarians of the time (proletarians being Boxer, the horse).

More Info: en.wikipedia.org