Besides the diffusionism controversy, in which Rapa Nui plays a part because of its geographical position as the most easterly inhabited point for voyages from Polynesia and the most westerly for voyages from South America, the other great issue in local history is population. While it may not be immediately obvious, it directly touches the creation and destruction of the moai.

According to oral tradition, Rapa Nui received two waves of immigration starting around the 5th century A.D., though the first material evidence is far more recent, about A.D. 800. Playa Anakena, the north shore’s sandy beach, was the ostensible landing place of Hotu Matua, leader of the eastern hanau eepe, while the hanau momoko arrived from the west. Many accounts portray these warring groups as “Long Ears” and “Short Ears,” because of the practice of earlobe elongation, but this is the result of Heyerdahl’s erroneous translation of terminology that, according to Georgia Lee, would more correctly be “corpulent people” and “thin people.”

In the aftermath of internal and external conflicts that nearly annihilated the population by the mid-19th century, oral testimony passed through a handful of survivors is, to say the least, an imprecise means of tracking local history. What seems clear, though, is that a growing population led to a remarkably complex and specialized society that produced the great monuments but which, when its limited land and sea base could support no further growth, disintegrated into a series of clan-based resource conflicts.

In its early centuries, Rapa Nui was a thinly populated island with a redistributive economy, but as the population grew its akiri (kings) and priests presided over a society where artisans fashioned the enormous moai and commoners performed the dangerously laborious process of moving the megaliths to the imposing ahu (altars or platforms) on which they would stand. This consumed enormous amounts of resources, including food and forests, until shortages ignited a series of wars; by A.D. 1600 or so, these conflicts had divided the island, toppled many of the moai that symbolically represented the lineages, and even degenerated into ritual cannibalism. In a situation that many modern scientists might interpret as a classic imbalance between population and resources, the society seen by the first Europeans was a precarious one, and things would get far worse before getting better.