The family of a preschooler missing from an outback homestead face an agonising wait for news as the search for the boy enters its fifth day.
Four-year-old August, known as Gus, disappeared from his family's sheep station in the remote South Australian mid-north on Saturday afternoon.
A major search of the area will continue on Wednesday as the boy's devastated family clings to hope he'll be found alive.
Alone in searing temperatures and without food or water, the best hope is that Gus has found shelter and is waiting to be rescued.
His distraught family earlier released a statement saying they were "struggling to comprehend what has happened".
"Gus's absence is felt in all of us, and we miss him more than words can express," Bill Harbison said on behalf of the family on Tuesday.
"Our hearts are aching and we are holding on to hope that he will be found and returned safely."
The adventurous boy had been playing in the sand near the family homestead when he disappeared.
Despite frantic efforts, his family found no trace and called emergency crews to widen the search around their property near Yunta, about 300km north of Adelaide.
Extensive ground searches involving State Emergency Service volunteers on trail bikes, all-terrain vehicles, dogs and a drone have been carried out, while helicopters, police divers and mounted officers have also been involved.
Fears are escalating for the safety of the missing boy, but police don't believe his disappearance is suspicious.
Superintendent Mark Syrus previously said police hadn't given up hope of finding the preschooler alive.
PolAir continued aerial searches throughout the night, but found no trace of the missing boy.
"We always work on the worst-case scenario - he hasn't had any water or food, but we're hoping that he's just crawled up underneath a bush somewhere and just stayed put, conserving some energy," Supt Syrus said.
"The human body is an amazing thing, and we're hoping that he's just stayed put, kept out of the sun."
Gus has long, blond, curly hair. He was last seen wearing a grey sun hat, a cobalt blue T-shirt with a yellow minion on the front, light grey long pants and boots.
