What events during the pigs dance in William Golding's Lord of the Flies shows the continuing loss of civilized behaviour and the increasing prevalence of savagery?
As the question implies, there has been gradual but steady deterioration in the civil society some of the boys, mainly Ralph and Piggy, have attempted to establish among the group struggling to survive on the island on which they have found refuge. William Golding's novel remains a fascinating portrait of such a deterioration among the category of humanity most expected to represent innocence and virtue: children. Two factions are emerging, with the group led by Ralph electing to adhere to a more reputable code of conduct then that led by Jack, the increasingly sadistic leader of the choir who has come to represent the less-civilized side of humanity. In Chapter Four of Lord of the Flies, titled "Painted Faces and Long Hair," early signs of the division into these two groups are provided, as Jack prepares to stalk the wild pig that the boys hope to be able to eat. Jack's preparations, involving an almost-ritualistic descent into another, more haunting dimension, is described as follows:
"He began to dance and his laughter became a bloodthirsty snarling. He capered toward Bill, and the mask was a thing on its own, behind which Jack hid, liberated from shame and selfconsciousness."
Submerged behind his mask of death, and commanding his followers, Jack is able to kill the pig and has his minions carry the dead animal back to camp. The full measure of Jack and his followers' break with civility now becomes frighteningly apparent, as they chant while approaching Ralph with their newly-killed pig, "_Kill the pig. Cut her throat. Spill her blood._" At this point in the story, the boys remain unified in their efforts at survival, but it is Jack's blood-lust, and his failure to maintain the carefully-cultivated fire necessary to signal passing ships, that presages the final coming break. Jack's attitude, however, reveals his diminishing sense of civility, as he, Roger, Maurice and, increasingly, the twins, celebrate their kill:
"Then Maurice pretended to be the pig and ran squealing into the center, and the hunters, circling still, pretended to beat him. As they danced, they sang. '_Kill the pig. Cut her throat. Bash her in._'
"Ralph watched them, envious and resentful. Not till they flagged and the chant died away, did he speak."
The celebration surrounding the pig is very much indicative of the growing schism between the boys. Ralph and Piggy are definitely of a different ilk than Jack and his miniature henchmen, and the former's reaction to Jack's celebratory dancing and boasting of having cut the pig's throat does not bode well for the unity the boys need to survive.