The pigs are simply the most intelligent animals on the farm in the book and it seems this is mostly true in real life. Pigs have been given a bad reputation, associated with wallowing in filth, etc. Yet, pigs are among the most intelligent of common farm animals if not the most intelligent.
I used this as a question on a web quest last year, and learned a lot of things about pigs that I had not known. I had no idea that pigs were so intelligent, for one thing. Pigs are also kept as pets by many people, and they are very human-like in many ways. We even use their organs as transplants!
This is a very interesting question. It might prove quite illuminating to go through the list of animals that Orwell uses and match their biological tendencies to how they are presented in the book. For the pigs, Orwell made a very conscious decision to place them in such a position in the text. On one hand, pigs are considered to be "highly social and intelligent animals." This is something...
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