When it gets hot, these bearded dragons change their sex

The World
A bearded dragon in Hunter Valley Zoo, Australia.

It's never been seen in the wild before now, as least in reptiles. Researchers have published a study demonstrating that when the mercury rises, the Australian bearded dragon changes its sex.

The study, in the journal Nature, refers to the change as "sex reversal"  which means that the bearded dragons actually have genes and sex chromosomes of a male individual, but they look, act, behave and, incredibly, reproduce just like females.

Even more surprising is the reason the sex reversal takes place. The researchers showed that by incubating the bearded dragon's eggs in very warm temperatures (above 89.6 degrees) you can trigger them to reverse sex.

The lizards switch from having their sex determined by genes to having it determined by temperature.

There are examples of sex reversals known in fish like the parrotfish that start life as females and change to males. There are amphibians as well. But, it's the first time the it has been demonstrated in the wild by a reptile.

Is this remarkable change a positive thing for the bearded dragon? That is, does this suggest that animals are adapting and surviving, or will something like the temperature increases from climate change ultimately lead to them becoming extinct?

"That’s actually one of the big questions that we don’t quite have an answer to yet," says Clare Holleley, lead author of the study. "There’s sort of two definite possibilities: If the climate does continue to warm exponentially and they don’t have a chance to adapt, then of course the populations are going to become increasingly female. If you go to the complete extreme where there is only females, that’s of course going to threaten the survival of the species."

However, there is a possibility that they may be able to adapt to climate change.

"Indeed, some could argue that maybe being able to manipulate your sex ratio by adapting and laying your eggs in different temperatures in different regions, could potentially be a benefit to the species," Holleley says. "We’re not too sure whether it’s a good thing or a bad thing yet."

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