1. Ralph is fairly well-liked, especially at first, and Piggy always struggles to find acceptance. Piggy finds himself at the receiving end of the group's jokes almost from the first moment they gather:

“He’s not Fatty,” cried Ralph, “his real name’s Piggy!”
“Piggy!”
“Piggy!”
“Oh, Piggy!”
A storm of laughter arose and even the tiniest child joined in.

Meanwhile, Ralph is quickly established as their leader even though "what intelligence had been shown was traceable to Piggy while the most obvious leader was Jack." Ralph has charisma and holds the symbol of power in his hands:

“Him with the shell.”
“Ralph! Ralph!”
“Let him be chief with the trumpet-thing.”

2. While Piggy struggles athletically and with his health, Ralph is agile and skilled at navigating the island. Piggy wears glasses, is overweight, and struggles with asthma, and the group taunts him with chants of "Sucks to your ass-mar!" Meanwhile, Ralph has a more athletic build:

You could see now that he might make a boxer...

When exploration groups are chosen, Ralph is quickly selected at least in part because he is capable of the athleticism required.

3. Piggy has insights and wisdom that Ralph lacks. Piggy claims that "Life...is scientific" and calculates their next best steps with a detached sense of reason. Ralph, on the other hand, is the voice piece of this reason since no one will listen to Piggy himself. But it is not Ralph who holds the highest cards in the deck of intelligent thought.

4. Piggy really doesn't change from the beginning of the book until his death. He realizes that he is an outsider, but this doesn't shape his vision for how the group should behave or silence him from speaking the truth. In his final words, Piggy is urging the group to see the reality of their situation:

“Which is better, law and rescue, or hunting and breaking things up?”

Ralph, on the other hand, grows into a more developed sense of wisdom through experience—and mistakes. It is Ralph who betrays Piggy right from the beginning, jokingly sharing that his name isn't "Fatty" but "Piggy," sacrificing the confidence Piggy has requested to earn himself favor from the group. Later in the plot, Ralph comes to value Piggy's wisdom.

5. Piggy never really determines the nuances of group behavior, and it costs him his life. It wasn't wise to openly challenge Jack's group so boldly. Jack, surrounded by his loyal followers, could not let Piggy's proclamations go unpunished. Roger, faithful to his alliance to Jack, kills Piggy with "delirious abandonment." Ralph, on the other hand, realizes his precarious situation near the end and goes into hiding:

There were many things he could do. He could climb a tree; but that was putting all his eggs in one basket. If he were detected, they had nothing more difficult to do than wait.

He narrowly escapes murder when an officer shows up on the beach to rescue him and the other survivors.

1. In terms of their physical appearances, Piggy is, broadly speaking, unattractive, whereas Ralph is considered attractive. Piggy, for example, is repeatedly referred to as the "fat boy," and his name itself also alludes to his size. Ralph, on the other hand, is said to have the physique of "a boxer" and "a mildness about his mouth that proclaimed no devil."

2. Ralph is athletic, whereas Piggy is not. Piggy struggles to run because of his asthma and because of his poor eyesight. Indeed, as he tells Ralph, his "auntie (has) told (him) not to run." Ralph, on the other hand, is very athletic. Piggy, watching Ralph swim, compliments Ralph, telling him, "You can't half swim."

3. Ralph is also, for the most part, very self-assured, whereas Piggy is awkward and self-conscious. For example, in Chapter 1, Ralph confidently strips naked to enjoy the sunshine, while Piggy is much more hesitant about taking off his windbreaker. Piggy is also self-conscious about his nickname and "clasp(s) his hands in apprehension" when he reveals it to Ralph and Ralph laughs.

4.Ralph is a natural leader, whereas Piggy seems more comfortable being a follower. The other boys (all except those in Jack's choir) quickly elect Ralph as their leader, and Piggy attributes this in part to "a stillness about Ralph that marked him out." Piggy, however, is content to help. In Chapter 8, for example, having fetched some wood for the group, Piggy is described as "so full of pride in his contribution to the good of society."

5. Piggy is more intelligent than Ralph. In Chapter 5, Ralph is described as "lost . . . in a maze of thoughts that were rendered vague by his lack of words to express them." In other words, Ralph lacks the capacity with language to articulate his own thoughts. However, Piggy is probably the most articulate of the boys. He is also perceptive. In chapter 5, Piggy asks, "What are we? Humans? Or animals? Or savages?" Here, Piggy shows how perceptive he is by identifying the savagery that is taking over the boys.

Five differences between Ralph and Piggy are:

1. Ralph is slim while Piggy is fat.

2. Ralph is athletic while Piggy is asthmatic and cannot even swim.

3. Ralph is confident while Piggy is awkward.

4. Ralph is a born leader while Piggy is clever.

5. Ralph is respected by the boys while Piggy is made fun of.

In chapter 1 "The Sound of the Shell", the characters are introduced. We are told in the first line of the novel that Ralph is "the boy with fair hair". The words "the fair boy" are repeated several times in the next few pages to differentiate him from Piggy, who is referred to as "the fat boy" repeatedly. It is also revealed that Ralph is athletic, which is the opposite of Piggy who is out of shape and overweight.

He was old enough, twelve years and a few months, to have lost the prominent tummy of childhood and not yet old enough for adolescence to have made him awkward. You could see now that he might make a boxer, as far as width and heaviness of shoulders went, but there was a mildness about his mouth and eyes that proclaimed no devil.

It is also revealed that Piggy, who has vision problems and wears glasses, can't swim. He tells Ralph, "I can't swim. I wasn't allowed. My asthma--". In addition to being out of shape, Piggy has trouble breathing.

Ralph is also confident and capable of leading, whereas Piggy, who is awkward, is not. Piggy makes up for his lack of leadership skills by being clever. For example, Piggy comes up with the idea of using a conch shell to call out to other survivors.

"Ralph!" Ralph looked up. "We can use this to call the others. Have a meeting. They'll come when they hear us--" He beamed at Ralph. "That was what you meant, didn't you? That's why you got the conch out of the water?"

All of these differences are established in the first chapter of the book. Though these two characters are very opposite, they are the most logical and clear-headed of the older boys on the island.