At the end of Animal Farm, the pigs start to walk on their hind legs. This is significant because the animals have gone from saying "Four legs good, two legs bad" to the chant "Four legs good, two legs BETTER." Napoleon begins carrying a whip, and soon all the supervisor pigs are carrying whips. Napoleon also is seen with a pipe in his mouth. The pigs literally wear the clothes straight from Mr. Jones's closet:
Napoleon himself appearing in a black coat, ratcatcher breeches, and leather leggings, while his favourite sow appeared in the watered silk dress which Mrs. Jones had been used to wearing on Sundays.
When Mr. Pilkington joins the pigs, he talks of how the pigs dealing with lower animals is similar to how humans must deal with lower classes. The other animals observe:
The creatures outside looked from pig to man, and from man to pig, and from pig to man again; but already it was impossible to say which was which.
The appearance of the pigs show how they have become the oppressors. They wear the humans' clothes, walk on two legs like humans, and use pipes and whips like humans. The whip further signifies oppression and the control the pigs have over others. The specific clothing is reflective of the upper class, as Mr. Pilkington suggests. The fact that the sow wear the best Sunday dress shows that the clothing is not worn for warmth or protection—it is worn to make a statement.
It is also important to remember that Napoleon the pig is reflective of Joseph Stalin and Napoleon Bonaparte.