Some 4,900 yellow-spotted river turtles, also known as tracajás, have been released into the Igapó-Açu River, in Brazil.
The threatened species lives in river basins in northern South America, and the Federal University of Amazonas has been running projects aimed at boosting turtle numbers for a decade.
In that time, more than 70,000 turtles have been set free to live in the wild.
