The nesting behaviour of two Australian freshwater turtles, the broad-shelled river turtle Chelodina expansa and the Brisbane river turtle Emydura signata are described.
Both species nest during, or soon after rain. C. expansa nests exclusively during the day while E. signata as a preference for nesting at night but can be found nesting during the day. C. expansa nests 30-300 m from the water's edge usually after walking up a hill, while E. signata typical nests just 2-10 m from the water's edge. Both species dig their nests exclusively with their hind legs by alternative scooping movements. Nest excavation takes from 20 to 180 minutes depending on how hard the soil is compacted. Typically some water is released from the cloaca during the nesting process but the role of this behaviour remains unknown. C. expansa uses a ‘body-slamming’ behaviour to compact the nest plug at the end of nesting but this behaviour was not observed in E. signata.