Left. Crystal bead. Right. Gilded bead. Both recovered during excavations at the site.
In the north, they dwelt in an estuarine landscape, where barrier islands encompassed broad bays. The southern reaches were a lattice of mangrove swamps that formed a mosaic of narrow channels accessible only by canoe. They exploited an unusually productive seawater habitat with an average depth of only half a metre. Unlimited sea food one might think, but reality was very different. The environment was far from homogenous and unpredictable. Perhaps most important of all, even very minor sea-level fluctuations could alter fisheries and mollusc beds within a generation or two. The Calusa never lived through centuries of predictable food supplies. Sudden climate changes and severe hurricanes affected the seemingly bountiful fisheries, as did sea-level changes in the shallow water that could be felt within a 25 to 50 year span. Everything had to be flexible and highly effective in a world of shallow sea-grass meadows, mangrove wetlands, and barrier islands. More than almost anywhere else in the world, seemingly insignificant sea-level changes could play havoc with fisheries and mollusc beds. Pine Island Sound and Estero Bay are classic examples, being never deeper than 1.2m, a depth that affected everything from siting houses to finding firewood and even food. We are still learning details of the climatic changes that affected Calusa life. For instance, sea levels around Pine Island north of Mound Key began to fall around AD 550 and fell by at least a metre by around AD 850. It became drier and cooler. Oyster populations declined, while marine snails became more abundant, especially whelks and conchs. Fish populations diminished as well. Warming began after AD 850, reaching a peak between 1000 and 1100, two centuries that coincide with part of a balmy period, known to us as the Medieval Climate Anomaly, that affected wide areas of the world. The clement centuries between 900 and 1100 saw a boom in the Calusa population, with hundreds, if not thousands, of people living on and around Pine Island and Mound Key. Current estimates place the Calusa population at 20,000 at the time of Spanish contact, a truly remarkable number for a society based almost entirely on fishing and mollusc collecting. Small wonder that the greatest concentration of truly massive shell mounds in North America occurs in Calusa territory.
The Past | April/May 2021