Male yellow-headed sideneck turtles court females by nipping at their feet and tails. During the evening, two weeks after mating (4), the female lays an average of 20 to 30 eggs in a fairly shallow nest (6), and these incubate under the heat of the sun for two months. The sex of the hatchlings is determined by the temperature at which they incubate. Eggs incubated below 32 degrees Celsius will hatch as males, and those incubated above 32 degrees Celsius will be females (7). Just a few days after hatching, the young turtles begin to forage for food alone. Food includes vegetable matter, grasses, fruits, leaves, carrion and molluscs. They are at risk of predation by humans, birds, snakes, large fish, frogs and mammals (4).
The yellow-headed sideneck turtle is diurnal and is most active in mid-morning and the afternoon. Groups of turtles can be seen basking in the sun on logs or stones in the middle of rivers, and they may also lie on the shore. As ectothermic (cold-blooded) animals, this behaviour functions to warm their bodies (2).