Marking the passage of time is ubiquitous among cultures, but the boys on the island in Lord of the Flies don't seem to think about it. Only Piggy considers making a sundial, but he abandons the useless idea. The boys function extemporaneously—they eat when they are hungry and sleep at night. They hold meetings on an ad hoc basis. They don't have any special days, like Sundays, to punctuate the sameness of their activities. Jack appears to establish a rotation among the boys who tend the fire, but that isn't enforced. Perhaps the reason Jack's feast is so attractive—besides the meat—is that it is the first celebration or event they have held.
Golding doesn't mar this lack of attention to time with any authorial intrusion. He doesn't tell readers how much time has passed. Since the island is tropical, no seasonal changes give readers a clue to how long the boys have been stranded. The only clues Golding gives readers are the mentions of the boys' hair and clothing. Ralph's growing hair bothers him at several points. In Chapter 7, Ralph longs to "have a pair of scissors and cut this hair—he flung the mass back—cut this filthy hair right back to half an inch." At this point, the boys have been on the island long enough for Ralph's hair to grow from half an inch to a "mass" that he can fling back. In chapter 11, it is long enough for Piggy to suggest that he could "tie your hair back." Ralph responds, "Like a girl!" His hair is long enough to tie back in a ponytail. Hair grows at various rates, but for hair to grow from half an inch to ponytail length would take months. A good estimate is that when the naval officer appears, Ralph has been on the island for several months.