<P> The wide diffusion of Olmec artifacts and "Olmecoid" iconography throughout much of Mesoamerica indicates the existence of extensive long - distance trade networks . Exotic, prestigious and high - value materials such as greenstone and marine shell were moved in significant quantities across large distances . Some of the reasons for trade revolve around the lack of obsidian in the heartland . The Olmec used obsidian in many tools because worked edges were very sharp and durable . Most of the obsidian found has been traced back to Guatemala showing the extensive trade . While the Olmec were not the first in Mesoamerica to organize long - distance exchanges of goods, the Olmec period saw a significant expansion in interregional trade routes, more variety in material goods exchanged and a greater diversity in the sources from which the base materials were obtained . </P> <P> Despite their size and deliberate urban design, which was copied by other centers, San Lorenzo and La Venta were largely ceremonial centers, and the majority of the Olmec lived in villages similar to present - day villages and hamlets in Tabasco and Veracruz . </P> <P> These villages were located on higher ground and consisted of several scattered houses . A modest temple may have been associated with the larger villages . The individual dwellings would consist of a house, an associated lean - to, and one or more storage pits (similar in function to a root cellar). A nearby garden was used for medicinal and cooking herbs and for smaller crops, such as the domesticated sunflower . Fruit trees, such as avocado or cacao, were probably available nearby . </P> <P> Although the river banks were used to plant crops between flooding periods, the Olmecs probably also practiced swidden (or slash - and - burn) agriculture to clear the forests and shrubs, and to provide new fields once the old fields were exhausted . Fields were located outside the village, and were used for maize, beans, squash, manioc, and sweet potato . Based on archaeological studies of two villages in the Tuxtlas Mountains, it is known that maize cultivation became increasingly important to the Olmec over time, although the diet remained fairly diverse . </P>

The olmec were the earliest known culture to develop in the gulf coast of mexico