The giant river turtle is one of the largest freshwater turtles in the world. They are also known as the arrau turtle, the South American river turtle, giant South American turtle, giant Amazon River turtle, Arrau sideneck turtle or simply the Arrau. Like sea turtles, these turtles are migratory, traveling hundreds of miles up and down rivers each year; each will dig its single nest for the season in a sandbank. After nightfall, they emerge and crawl somewhat cautiously to the highest ground, advancing haltingly in overlapping swarms of movement, ever ready to retreat tumultuously into the safety of the river. Hundreds of turtles can be seen nesting and crawling in the moonlight, scraping the sand, digging body pits and nesting chambers and spraying sand.