The large island of Marajo at the mouth of the Amazon was a favoured area for settlement from early times. By 1400 BC, people lived in small villages here, making pottery and probably cultivating manioc (cassava). Later, maize became their staple, a crop better suited to Marajo's seasonally flooded terrain.
Aquatic resources, such as fish, turtles and shellfish, provided valuable protein into historical times. Settlements were built on artificial mounds raised above the flood levels. A village dated AD 400-1300 was excavated at Teso dos Bichos. By this time the island's population had grown enormous: this village alone is estimated to have held 1000 people.
As in earlier times, the houses were large communal dwellings. Finds suggest they were occupied by extended families, and that during the day the women shared domestic activities in the communal houses while the men had a separate house.
Upon the women devolved much of the labour of the settlement, including cultivation, while the men may have added warfare to their role as hunters and fishers. The settlement was defended by a substantial earthen wall, against floodwaters or neighbours.
About 100 such mound sites have been discovered in the island. Some supported villages, others cemeteries.
