Plant remains on Marajo Island show a subsistence pattern that relied heavily on small seed crops, as well as small fish, which were either cultivated or protected by indigenous peoples. Many of the carbonized seed remains have not yet been identified, though they seem to be herbaceous and derived from local grasses (Roosevelt 1991: 377, 405). Trees such as the açai and tucuma palms also provided important supplements in the Marajo diet, as well being used for manufacturing items such as baskets or canoes (Roosevelt 1991; Meggers 1957). Evidence from human remains show that Marajo peoples limited their consumption of starchy root crops like manioc; rather, the heavy wear patterns of teeth suggest a diet based predominantly on seed crops, tree fruits, and fish (Roosevelt 1991: 394-395). Since small fish make up the majority of biomass fauna and there are relatively few terrestrial animals, it follows that pre-historic peoples focused on the abundant populations of small fish (Roosevelt 1991: 23). The method for catching fish was likely very similar to present-day techniques, which involves stunning fish with the poisonous liana plant and collecting them as they float to the surface. This method of mass harvesting is not as useful in the rainy season as it is during the dry months when fish are trapped in receding streams or ponds (Roosevelt 1991: 382-383).