Looking west across the Simpson Desert there is dune and swale, dune and swale, a patterning across an emptiness. No people or animals, just scattered tracks across the dune-tops each morning: a beetle, a hopping mouse, an unwelcome cat.  Birds announce dawn and dusk but disappear all day.  The emptiness is chilling. To get lost would be death.

But below the dune, to the east, the camp of Australian Desert Expeditions houses those, like me, who find the place intriguing. Smoke rises from the campfire. Two rows of camp saddles, water jerries and boxes show where the camels were unloaded; they’re now out grazing, hobbled and happy at the end of the working day.

I’m here with Australian Desert Expeditions as a paying guest, my third time in the Simpson, feeding a growing addiction to desert walking.

Crossing paths

Dr Karl Vernes is coming out of the desert as we go in. Our paths cross in Birdsville as he searches for the vanished. His crowd-funded quest to find the Desert Rat Kangaroo has made media headlines, and I’m keen to meet him.

He, on the other hand, is intent on gluing teeth into a camel skull, a desert trophy to take back to the office. Tanned, skin layered with desert dust and a 10-day beard, he leaves talking for later at the Birdsville pub.

Searching across the centuries

Vernes is a conservation biologist at the University of New England.  Small kangaroos are his speciality, and he’s looking for any hint that the Desert Rat Kangaroo survives.  He is literally following the footsteps of earlier hunters like Hedley Herbert Finlayson, an honorary associate and curator at the South Australian Museum who travelled into the central deserts during the 1930s to collect specimens of the Desert Rat Kangaroo.

A small rabbit-sized creature, plump-bodied with soft buff fur, small ears and an inquisitive gaze, the Desert Rat Kangaroo had been missing for almost a century when Finlayson set out.  He actually thought the species already extinct.  A skin and skull sent to Finlayson by Lou Reese, a pastoralist and naturalist from the far north east of South Australia, was all the invitation he needed to begin his quest.

Vernes’ 21st century research strategy involves camera ‘traps’, spotlighting and collecting predator poo. The challenge, as it was in Finlayson’s day, is to find anything.

Walking the country

Australian Desert Expeditions is also seeking to fill the emptiness with knowledge.

Over the past five years, ADE has run camel-supported expeditions across remote parts of the trackless Simpson Desert, conducting daily surveys of plants, birds and Aboriginal artefacts, and nightly pitfall trapping for the small animals at home in the dune tops.

Max Tischler, ADE’s chief scientist, cameleer, guide, desert guru, and great camp cook, explains that these expeditions are about walking the country, doing what people did for millennia.

“Those people aren’t walking it anymore, but we are,” he says. “With honour and respect. By walking, we see the subtle changes in the landscape, things you can’t see from a 4WD.”

Each night on this expedition we dig pit-fall traps.  Each morning, kneeling on the sand, Tischler’s shirtless arm reaches into each pit to bring out any creatures that hit our ankle-high fence and slipped into a trap.

We watch, hoping for a rare creature; for Tischler, they are all important. It’s science and no one else is studying the Simpson Desert with this intensity.

Walking the songline

This last expedition of the May-September season is following a songline – Two Boys Dreaming – in partnership with the Wangkangurru Yarluyandi traditional owners.

Tischler hasn’t walked through this part of the desert before, and perhaps no one has since Aboriginal people left these parts more than 100 years ago.

Walking east in an arc, we are scouting for evidence of the route Aboriginal people walked from the Diamantina River through to a string of hand-dug desert wells – mikiri – that enabled people to go far into the desert.

As we head out to the desert, Vernes goes south down the Birdsville Track to Koonchera dune, one of his study sites. It stretches south from the stone-covered gibber plains to a permanent waterhole, part of the big flood-out area of the Diamantina River.

This is Vernes’ third trip, retracing past sightings and captures of the Desert Rat Kangaroo. “Looking out at the vastness of the landscape, I’m thinking that I could miss this animal quite easily if I didn’t get the right patch of habitat that it’s hanging on in,” he says.

But is it hanging on?

Colonial settlers were intent on discovery.  Their pre-Australia world was filled with strange creatures ready to be collected, named, catalogued and traded to museums across the world.

Specimens of the Desert Rat Kangaroo were sent to the British Museum as early as 1843, where John Gould drew their likeness, never having seen one alive. Where these specimens were collected remains a mystery.

Finlayson’s last specimen collected in 1935 lies disarticulated in the Northern Territory Art Gallery and Museum.

Like the photograph of the last thylacine, these stretched-out skinless bones are bleak evidence of past collecting, and a history of neglecting.

The oolacunta may be the only ‘rediscovered’ Australian mammal to have become extinct.  Perhaps it was already on its way out.

Finlayson’s methods were based on what he had, says Vernes. “He had horses and camels and basic equipment. He was sitting around the fire every night wondering what’s happening out in the desert behind him and he had to wait until the sun came up before he could get back to work on an animal that’s nocturnal.”

Finlayson’s strategy was to ride through the open plains until, by chance, a rat-kangaroo was flushed out of their nest, and then run them to exhaustion.

Vernes explains: “Like other related species, the rat-kangaroos create a nest of grass in a little ground scrape, tucked under a bush, and that’s where they spend the day. They will have multiple nests and they’ll tear off from one nest and go to another that they know is safe.”

Recounting his exploits in Melbourne’s Australasian and Adelaide’s Advertiser, Finlayson wrote: “It was only after much straining of eyes that the oolacunta could be made out at all, a mere speck 30 or 40 yards ahead. At that distance it seemed scarcely to touch the ground, but almost floated ahead in an eerie, effortless way that made the thundering horse behind seem, by comparison, like a coal hulk wallowing in a heavy sea.”

But in fact, the first caught oolacuntas – a female and her joey – were shot, without a heroic chase.

Finlayson was not alone in his quest. Lou Reese went with him, as did his hand-picked team of four “blacks”: a “Yalliyanda boy, Butcher” who had first-hand knowledge of oolacuntas, “Wonka-maroo hunter, Jimmy” and two others.

Their camp was on a stony plain – the gibber – where the Wangkangurru and Yarluyandi men were confident of locating Finlayson’s “coveted Caloprymnus”.

Finlayson was dubious.

But the location was right, and the group sighted 17 oolacuntas and killed nine for museum specimens.

Butcher told Finlayson he could catch the oolacunta by hand, describing the technique in detail, and he delivered on his promise, producing a “beautiful fully grown adult oolacunta and a half-grown joey”, alive and undamaged, offering “good life studies for a camera”.

Finlayson wrote that “(the) Yalliyanda boy had … spotted a nest and noted the head of the occupant in the opening watching the party.  He rode on without pause for a quarter of a mile, then, leaving his horse, made a rapid stalk up the wind and grabbed both mother and babe from behind.”

Wangkangurru Yarluyandi people lived in the Simpson Desert; their songlines and trade routes cross the desert, linking them to other Aboriginal peoples to the west, north and south.

Oolacunta, the Desert Rat Kangaroo, was food, its skin turned inside out and stitched into waterbags, its name marking desert locations.  For Wangkangurru Yarluyandi, the oolacunta was never lost.

A slow vanishing

Extinction is a special kind of disappearance: extinction means forever.  In the climate change debate, humans are blamed for heating the planet, and therefore for extinctions.

It’s a harsh judgement. The Extinction Rebellion, a social media-based lobby, says we are facing the sixth extinction. Modern humans – homo sapiens – weren’t around for the first five.

Mass extinction events are rare. Five in the last 540 million years or so all happened prior to humans. Each time, the earth lost more than 7 per cent of its species; mass extinctions wipe the slate pretty clean.

Scientists debate when the sixth mass extinction started, what caused it or how the current species decline will end. Some say it started when modern humans expanded out of Africa 100,000 to 200,000 years ago, or perhaps more recently, at the end of the last ice age.

Australia has excelled in species’ extinction according to ecologist Chris Johnson in his time travellers’ guide to these vanishings, Australia’s Mammal Extinctions: A 50,000-year history.

He recounts three waves of extinctions: the first two probably witnessed by Aboriginal people who were living across the Australian continent at least 40,000 years ago. The third, most recent wave starts with British colonial occupation and hasn’t finished yet.

Since British colonial occupation 200 years ago, 18 species have gone, almost half of the 40 mammal species worldwide that have disappeared. Those like Tischler and Vernes who study Australia’s arid deserts, fear another wave of extinctions.

A slow burn

In the boom and bust cycle of the desert, life is always on a knife’s edge. Tischler thinks the loss of people, their knowledge and management practices – especially fire – created a tipping point for many desert species.

Sheep and cattle grazing, combined with stock watering points enabled foxes to expand their range, and rabbits turned the country inside out.

Two or three decades after Wangkangurru Yarluyandi people left the desert, Tischler thinks the landscape had changed, perhaps forever.

But the extent of change is hard to assess, with so little of the desert documented.

Down at Koonchera dune, Vernes says the habitat hasn’t changed, and he was surveying right where Finlayson had such success, but to date no Desert Rat Kangaroos have been found.

Perhaps Finlayson’s success coincided with the last boom of the Desert Rat Kangaroo.

Is it more powerful to posit a sixth extinction, or to emphasise that this one will be the first mass extinction of human-making?

Vernes is interested in this question. He suggests that thinking about climate change in a human-selfish way is smart.

“We’re pretty good, as a species, of being selfish about our wants and needs. We should be thinking, ‘Damn, this place is going to be hell to live in for generations to come unless we do something about it’.”

He tells his conservation biology students that it took 10 to 20 million years for biodiversity to be recovered after those first five mass extinction events, and reflects, “we need the planet. It doesn’t need us.  It’ll recover”.

And humans too will vanish: “99 per cent of all species that ever existed on Earth are now extinct. Every species has its day. Humans will as well. The planet will go on.”

For those documenting the vanished or vanishing, it is also a matter of the heart. Sitting at the campfire with Tischler, I want to know how he feels about the landscape’s emptiness.

He says for him “the desert rattles with skeletons and ghosts of the past” and expands with a story.

He tells me about a trip with renown linguist Luise Hercus who recorded the language and songs with Wangkangurru Yarluyandi elders over four decades from 1965.

“Luise was trying to place a location associated with the Fire songline and kept asking me where it might be. I thought it might be a huge claypan where there are blackened rocks and petroglyphs.

“We went there together, and it was the place. On her laptop, Luise played the voice of Wangkangurru elder Mick McLean singing verses of that songline, and the landscape went quiet. The land hadn’t heard that song for a century. For me it was one of those moments. The country was yearning to hear the song.”

The singer, McLean was part of the second last Wangkangurru family to leave the desert in the summer of 1899-1900. For that long journey, they carried their water in skins bags made of hare-wallaby and rat-kangaroo

Vernes is motivated by doing the right thing by the animal. “I could sit in my office at the University of New England for the rest of my career and wonder if the animal’s out there in the desert or I could actually go out there and look for it. That was the motivation really.”

He admits it is an adventure, and potential a great rediscovery. And if the Desert Rat Kangaroo is out there, Vernes will advocate for its protection.

Tischler’s quest is different.

If the desert is profoundly empty, what is missing are the songs. His remedy is to bring people back on Country. Using surviving knowledge and recreating a human-based burning regime will help prevent the devastating lightning-strike fires that risk the long-term survival of the spinifex grasslands, he says. Fires could tip more species into extinction.

How many lifetimes of walking would I need to do to chance upon the tracks or nest of a Desert Rat Kangaroo?

What else teeters on the edge, about to disappear from a desert that already feels empty at this dry end of the seasonal cycle?

Each day of the 10-day trek, I collect predator scats. A bag for the morning, another for the afternoon. Carefully labelled to connect each collection to our traverse, they will all be analysed in the hope of finding digested rat-kangaroo DNA.

The desert looks different this time. With every step, my desire to connect more deeply to this desert grows. I too want a quest.