The Calusa were once the dominant power in southern Florida. Numbering about 40.000 around 1500 AD, they dominated neigbouring tribes. Their society was stratified with a ruler having almost royal powers, or at least it seemed that way to the Spanish who were the first Europeans to make contact with them. Speaking a language possibly related to Tunican in the lower Mississippi Valley, they formed a paramount chiefdom based not on agriculture but on the rich marine resources of their land.
As with other Native American groups in Florida, Calusa society collapsed as a combination of European-derived disease epidemics and genocidal policies of the expanding Spanish Empire. The last remnants of the Calusa were in the Florida Keys around 1700. They may have been relocated to Cuba along with other remnants of Native Americans from Florida, or they assimilated later into the Muskhogean-speaking Seminoles who migrated into Florida much later. Descendants could possibly be found in Cuba, among the Seminoles in Florida or even in the Florida Keys.