Giant South American turtle  (Podocnemis expansa)

The giant South American turtle is the largest river turtle in South America (7). It has a broad, domed and streamlined carapace for active swimming in moderate river currents (3). The colour may be influenced by the algae that is attached to it (2), but is usually olive green to brown in colour (5). This turtle belongs in the family Pelomedusidae, which contains the side-necked turtles, and has a long neck which can be withdrawn horizontally within the shell, leaving it partly exposed, rather than retracting it in a vertical ‘S' bend as in most other turtles (3).