What does the pigs' ability to walk on two legs symbolize?

The pigs' ability to walk on two legs symbolizes the complete transformation into oppressors. Throughout "Animal Farm," the pigs start with the ideal of creating an equal society free from human tyranny. However, as they gain power, they begin to adopt the behaviors and traits of the very humans they initially overthrew. Walking on two legs signifies their embrace of human characteristics and their departure from the principles of Animalism, ultimately reflecting their role as oppressors in the society they helped to create.

This transformation culminates in the moment when the other animals can no longer distinguish between the pigs and the humans, highlighting the irony that the pigs have become indistinguishable from those they initially sought to replace. This shift illustrates the central theme of corruption and betrayal of revolutionary ideals, as the pigs, once champions of equality, become the new tyrants.