Half of Western Australia's Indigenous population has a genetic mutation that has helped them survive the tough central Australian climate for generations, researchers say.
A team of scientist from the University of Cambridge examined data from the 1980s and found half the Aboriginal people studied had varying levels of the hormone thyroxine, which regulates metabolism.
The genetic mutation helps the body alter its temperature in response to fever, scientists say.
"There is a special mechanism that gives a surge of release as the body moves into fever and the changes in Aboriginal [people] have in fact cancelled this trigger that causes the surge of release," said Emeritus Professor Robin Carrell.
"They can meet a situation where they have a higher body temp without having to accelerate the activity of the whole of the body.
"Immediately one can see how that would be of advantage to people living nomadic life in a very hot and arid climate."
The extreme temperatures in central Australia can pose health risks, particularly for children. But researchers say the genetic mutation helps them to cope and survive.
"If you look at threats there are historically, we're talking now in terms of 10,000 or 20,000 years, it's the diseases of childhood - dehydration, heat exhaustion that accompany dysentery and other common infections of childhood," Professor Carrell said.
"So the likelihood is that people who have this change would be better equipped to survive in conditions of central Australia.
"It protects them against the side effects of infection."
Aboriginal people with the mutation have a slight advantage over those who do not, researchers said.
"But that is enough over hundreds of years for it to become incorporated as a genetic change that has passed through generations," Professor Carrell said.
He says the findings provide an insight into human physiology.
"The fact that the Aboriginal Australian have adopted this change provides confirmation that the release of thyroxine really is of significance to the health of individuals," he said.
"The fact that it needs to be changed under these exceptional circumstances indicates it's a process that's happening that affects the body and makes us think of other things, for instance, don't laugh, of saunas and hot baths."