George Orwell uses the occasion of Old Major's speech to present an array of characters with different personalities, who therefore react differently to the senior animal's message.
Old Major himself is respected by the other animals in part because of his age, but Orwell makes it clear that he is exceptionally smart and insightful and believes that everyone should be treated fairly. His identity as a boar also points toward the superiority of the related pigs.
The author also uses the audience seating arrangement to indicate the hierarchy among the different species of animals. The pigs have priority, as they sit up front, and behind them are sheep, cows, and horses. However, not all species are included in the audience. The rats, who are not farm laborers or producers of useful resources, are outsiders, and the dogs try to exclude them. This police-like function of the dogs foreshadows their later application by the ruling pigs.
Another distinguishing species feature, with which Orwell begins to firmly establish their humanlike qualities, is the pigs' intelligence. They are quick in learning the song lyrics, as all join in the rousing Beasts of England. The individual distinctions within a species, such as the contrast between the pigs Napoleon and Snowball, soon becomes as important as those between different species.