Science says climate can turn outback male lizards into females

Australian bearded dragon, Pogona vitticeps, in the wild. Image: Arthur Georges

Scientist have confirmed for the first time that climate can cause male Australian lizards living in the wild to turn into females.

The researchers have been able to show that the sex determination process of bearded dragon lizards can switch rapidly from one determined by chromosomes to one governed by temperature.

Clare Holleley, a postdoctoral research fellow at the University of Canberra’s Institute for Applied Ecology, says:

“We had previously been able to demonstrate in the lab that when exposed to extreme temperatures, genetically male dragons turned into females. Now we have shown that these sex reversed individuals are fertile and that this is a natural occurring phenomenon.”

The study, published in the international journal Nature, looked at 131 adult lizards and used controlled breeding experiments.

Molecular analyses showed that some warmer lizards had male chromosomes but were actually female.

“By breeding the sex reversed females with normal males, we could establish new breeding lines in which temperature alone determined sex,” she says.

“We also found that sex-reversed mothers – females who are genetic males – laid more eggs than normal mothers. So in a way, one could actually argue that dad lizards make better mums.”