On previous visits, groups of some 20–40 individuals were encountered regularly. Habitations of 40–60 individuals were found on two occasions. As some individuals are thought to be hiding, a more precise approximation of group size cannot be determined. This would suggest that some 2–6 groups occupy the island. The rule of thumb population density of 1.5 km2 (370 acres)/individuals in comparable hunter–gatherer societies indicates that one such group could live off the land alone. A significant amount of food is derived from the sea. It seems that, at any one time, the groups that were encountered could only have come from a rather small part of the island, and that about half of the couples had dependent children or included pregnant women. There appeared to be slightly more males than females.