Ancient Americans ate lots of oysters in bad times

During a time of hardship, Native American peoples of the Southeast sought solace in oyster feasts, a new study has found. Analysis of archaeological remains on Roberts Island, a shell mound complex off the central west coast of Florida about 50 miles north of Tampa Bay, found that people gathered there for ceremonial purposes even when resources were severely curtailed by climate change.

Built and maintained by a small group of local residents, Roberts Island and Crystal River, its larger, more glamorous ceremonial site next door, drew people of different cultural groups who traveled long distances to celebrate there. As with other ancient Native American ceremonial sites (Poverty Point for example), the Roberts Island complex was a gathering place of immense social and cultural diversity. It was built after the decline of Crystal Island around 650 A.D., and remained in regular use until around 1050, one of the last of the ancient religious sites that had once flourished all along the Eastern seaboard.

It consists of three platform mounds arranged in a rough triangle forming a central plaza between them where people would gather to watch the ceremonies taking place atop the mounds. The mounds were originally pyramidal, built from midden materials that were deposited one basket at a time. The bases of the mounds covered thousands of square feet in area and the mounds could reach more than 30 feet in height, so they must have taken a huge number of basketsfull to build.

The locals who built and maintained Roberts Island hosted thousands of visitors who descended upon it for a month or two out of the year to participate in community feasts and religious celebrations, including burials and marriages.

Researchers collected samples from mounds and middens at the two ceremonial sites, identifying the species present and calculating the weight of the meat they would have contained. They found that feasts at Roberts Island featured far fewer species. Meat from oysters and other bivalves accounted for 75% of the weight of Robert Island samples and roughly 25% of the weight from Crystal River. Meat from deer and other mammals made up 45% of the weight in Crystal River samples and less than 3% from Roberts Island.

[Lead study author C. Trevor] Duke said evidence suggests that Roberts Island residents also had to travel farther to harvest food. As sea levels fell, oyster beds may have shifted seaward, possibly explaining why the Crystal River population relocated to the island, which was small and had few resources.

“Previous research suggests that environmental change completely rearranged the distribution of reefs and the ecosystem,” Duke said. “They had to go far out to harvest these things to keep their ritual program active.”

No one knows what caused the widespread abandonment of most of the region’s ceremonial sites in A.D. 650, Duke said. But the production of Weeden Island pottery, likely associated with religious activities, ramped up as bustling sites became ghost towns.

“That’s kind of counterintuitive,” he said. “This religious movement comes on really strong right as this abandonment is happening. It almost seems like people were trying to do something, create some kind of intervention to stop whatever was happening.”

Man, this makes me miss my local $1 oyster happy hour even more than I did before. The study has been published in the journal Southeastern Archaeology.