As the novel progresses, the animals become increasingly more human. Let me give you a few examples.
First, the text says that the pigs learned how to read in the last few months. They learned to read from Mr. Jones's children's old books. From this perspective, we might argue that the pigs are more intelligent than humans. Here is the quote:
The pigs now revealed that during the past three months they had taught themselves to read and write from an old spelling book which had belonged to Mr. Jones’s children and which had been thrown on the rubbish heap.
Second, the pigs create laws. In fact, they create seven commandments that govern the farm. In this way, they have created a society that is governed by law and order.
They explained that by their studies of the past three months the pigs had succeeded in reducing the principles of Animalism to Seven Commandments. These Seven Commandments would now be inscribed on the wall;
In light of this point, it is no wonder that the pigs also begin to work with their "hands" and build things, such as the windmill. This shows that they are architects of society as well.
Finally, at the end of the book, Napoleon turns into a man! The transformation is final, but it was taking place all along.