Australian researchers reverse gender of bearded dragons to female which lay eggs, but act like males

Researchers from the University of Sydney had reversed the gender of bearded dragons (Pogona vitticeps) by incubating eggs at different temperatures. By increasing the incubation temperatures above 89.6 degrees Fahrenheit (32 degrees Celsius), the genetically male reptile is transformed into a functional female.

The 20 sex-reversed females even laid more eggs than bearded dragons born female, but it retained male characteristics and are more male in behaviour than those born male. The study, published on Wednesday in Proceedings of the Royal Society, used standard trials to measure the masculine behaviour of the sex-reversed lizards.

The animals were measured for their boldness, activity level and exploratory behaviour. The scientists also examined the physical characteristics of the bearded dragons such as its body temperature and tail length, reports Livescience.

To measure activity level, the bearded dragons – usually found in Australian deserts – were observed for frequency of head movements when inspecting a plastic container. For boldness, the measure was time elapsed before the bearded dragons came out from a shelter into an open area.

The sex-reversal only provided the bearded dragons capability to reproduce and lay an egg, but the animal retained a lot of its male-like personality characteristics. The ability to maintain male characteristics could make the lizard more successful in the wild, its natural habitat, says Professor Rich Shine from the university’s School of Life and Environmental Sciences and co-author of the study.

That evolutionary transition usually takes place over thousands of years, according to biologists. But they managed to speed up the replacement process dramatically. Under natural conditions, the process of producing bearded dragons with the bodies of female and brains of males happen to some degree.

But the study showed “Sex in dragons is clearly a much more complicated matter than we have assumed,” says Shine. He admits the evolutionary significance of the situation is still unknown “but field studies on the ecology of these remarkable lizards could answer some very general questions in reproductive biology.”

The sex reversal could help the bearded lizard find more food and have higher chances of survival. But in other circumstances, it could also make it more vulnerable to predators, researchers say.

VIDEO: High Temperatures Turning Australian Male Reptiles to Females