I thought I'd bring this to the top because it is really interesting.
The following is from an email exchange from and acquaintance. I thought it was great and also thought some of you might appreciate it.
The question was if Galaps had TSD (not all chelonians do) and if there were any studies which provided the crossover(not all are 30c) temperature.
Ans:
Galapagos tortoises indeed have temperature-dependent sex determination. The critical temperature appears to be about 29 degrees C. At 25.5 degrees, 84% are male. At 29.5 degrees, 33% male and 67% female. At 33.5 degrees, little if any development. The CDRS now deliberately produces males at 28 degrees and females at 29.5 degrees. Of course, nature uses fluctuating temperatures – Galapagos can be very hot by day and cool by night, and for several seasons the incubators at Villamil also used fluctuating temperatures because the electricity supply was cut off at night.
-----
Ed @ Tortoise Keepers
Trying to keep the fun in Chelonian care
