 The three traits of pivotal temperature (the temperature at which the sex ratio is 50%), maternal nest-site choice, and nesting phenology have been identified as the key traits of TSD that can change, and of these, only the pivotal temperature is significantly heritable, and unfortunately, this would have to increase by 27 standard deviations to compensate for a 4 °C temperature increase.It is likely that climate change (global warming) will outpace the ability of many animals to adapt, and many will likely go extinct.However, there is evidence that during climactic extremes, changes in the sex determining mechanism itself (to GSD) are selected for, particularly in the highly-mutable turtles.