Pluckhahn photo 2 (IMAGE) University of South Florida Caption Fossilized bones of Sirenians (the order that includes past and present manatee species), such as these examples from a site in Tampa Bay, are not uncommon on archaeological sites in Florida. But unfossilized bones of more recent manatees (from the last 12,000 years) are quite rare — suggesting sea cows may have been infrequent visitors to the Florida peninsula before the modern era. Credit Thomas J. Pluckhahn Usage Restrictions NA License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.