Ralph and Piggy are the first characters to appear in Lord of the Flies. When Piggy is first described, he is compared to the "fair haired boy" (Ralph) who is mentioned first. To be blunt, Piggy is short and fat:
The naked crooks of his knees were plump, caught and scratched by thorns. He bent down, removed the thorns carefully, and turned around. He was shorter than the fair boy and very fat.
Until they introduce themselves, Piggy is referred to as "the fat boy" and Ralph is "the fair boy." This is significant because Piggy will be the subject of mockery and Ralph will soon establish himself as the "fair" leader (fair, meaning just and honest). Piggy also notes that he has asthma and is not supposed to run or swim.
Ralph is much more athletic and fits the description of a young boxer:
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.
Ralph reassures Piggy that his dad, a commander in the Navy, will save them. Piggy's father is dead and he frequently mentions his aunt who had taken care of him and spoiled him with candy. Piggy does recognize that the conch could be used to summon the other boys; this shows Piggy's intelligence and thoughtfulness. Ralph does laugh at Piggy's name but he eventually takes Piggy under his wing. Ralph is the first to use the conch to summon the others and quickly establishes himself as a natural leader.