Thermal characteristics and sex determination in field nests of the pig-nosed turtle, Carrettochelys insculpta (Chelonia: Carettochelydidae) from nort

A. Georges
Australian Journal of Zoology, 40, 5, 511-521,
Carettochelys insculpta lays its eggs in shallow nests constructed in clean fine sand adjacent to water. Six nests had the following thermal characteristics: (1) core temperatures ranging from 26.1 to 33.7C early in September, from 30.0 to 38.7C early in October and from 28.4 to 36.8C early in November; (2) a pronounced daily cycle in core temperatures of up to 6.4C in amplitude, with the minimum occurring after sunrise in mid-morning and the maximum occurring in the evening; (3) a difference in the temperatures experienced by the top and bottom eggs in a single nest of up to 3.5C at any one time. Nest heating and the maximum temperatures achieved were principally driven by solar irradiation, not ambient air temperatures. Hot nests produced females exclusively, nest intermediate in temperature produced a mixture of sexes, and the sole cool nest produced males exclusively. In nests that produced both sexes, males emerged from the deepest coolest eggs whereas females emerged from the shallowest eggs. http://aerg.canberra.edu.au/cgi-bin/pubs_archive.cgi?target=G