The long-lived, lumbering reptiles have captivated sailors, conservationists and tourists alike. Robust enough to survive long sea journeys, sailors once considered their fresh meat a delicacy, and they were also exploited for their oil.
The largest freshwater chelonian was Stupendemys geographicus, a prehistoric side-necked freshwater turtle that lived about 13 million to 7 million years ago, during the Miocene. It grew to a height of 4 meters (13 ft) and weighed 1.25 tons (1.4 US tons). The only chelonian larger than this species is the large prehistoric sea turtle Archelon ischyros, which is estimated to have weighed more than 2.2 tons (2.4 US tons). S. geographicus lives in lakes and rivers in what is now Colombia and Venezuela in northern South America.
Fossilized male specimens of S. geographicus are easily distinguished from females by a pair of prominent frontal horns on either side of their shell, very close to the neck. Scientists believe that these horns were probably used as weapons, like spears, to fight with other males for territory or for mates, as deep scars have been recorded in their fossils.
