Divers exploring a southern Florida (USA) sinkhole have uncovered clues to what life was like for some of America's first residents. Led by University of Miami professor John Gifford, underwater archaeologists are exploring Little Salt Spring, 12 miles (19 km) south of Sarasota. Earlier this year, students working about 30 feet (9 meters) below the surface found the remains of a gourd that probably was used as a canteen by an ancient hunter about 8,000 or 9,000 years ago, according to Gifford.
     Archaeologists have been recovering primitive relics from the spring since 1977, when divers found the remains of a large tortoise and a sharpened stake that may have been used by a hungry hunter to kill the animal 12,000 years ago. In 1986, Gifford and his colleagues recovered a skull with brain tissue from what he thinks was an ancient burial in shallow water near the spring. He continues to work with DNA samples to determine the date of the find. Gifford and other archaeologists found more from the tortoise, along with the slaughtered remains of a giant ground sloth. The discovery of the sloth's bones, Gifford said, could indicate that Little Salt Spring was a sort of ancient butcher shop where hunters often killed and their prey and prepared meat when this was dry land.
     These remains come from the earliest known period of human activity in the Western Hemisphere, said Gifford, who has received funding for his work from the National Geographic Society's Committee for Research and Exploration. "This is a warehouse of environmental, natural, historical, and archaeological remains in a very, very well preserved environment," said Roger Smith, Florida's state underwater archaeologist.
     Sinkholes in Florida form when water from underground aquifers dissolves the porous limestone bedrock and pushes toward the surface. Eventually, the ground collapses into the water and an hourglass-shaped sinkhole is formed. When Little Salt Spring was formed during the last Ice Age, sea level was lower and what is now the Florida peninsula was much wider. Sources of freshwater were scarce. Ancient Native Americans came to the sinkhole to drink the water and perhaps find a meal.
     Gifford's divers will return to lower depths of Little Salt Spring soon, but will wait until their recent finds have been analyzed. They hope to eventually uncover evidence of campfires on the ledge. And because Little Salt Spring's waters contain little or no oxygen that would support bacteria that eats away at artifacts, it's possible they'll find near pristine items. "There may be lots of stuff—basketry, woven fabrics, wooden implements—that you wouldn't otherwise find in an archaeological context," said Bruce Smith, curator of North American Archaeology at the National Museum of Natural History in Washington, D.C.

Source: National Geographic News (18 February 2009)