The Desert Rat-kangaroo—Found, Lost, Found and Lost Again…

For the Wangkangurru, an Aboriginal people, the desert rat-kangaroo (Ngudlukanta) had been known for thousands of years. But Western science only became aware of the marsupial from the rat-kangaroo family (Potoroidae) in the 1840s, when the then governor of South Australia, George E. Grey, sent three specimens to the naturalist John Gould in England. Gould, actually an ornithologist, recognized it as a previously unknown species and scientifically described it in his 1843 publication On a New Species of Kangaroo Rat.

Afterwards, the desert rat-kangaroo was almost forgotten—for nearly 90 years there were no confirmed sightings, apart from a dubious report from 1878. Since no further evidence emerged, the species was eventually considered extinct.

Desert rat-kangaroo – fact sheet

alternative names	Buff-nosed rat-kangaroo, Plains rat-kangaroo, Desert bettong, Plain-loving jerboa kangaroo, Oolacunta, Ngudlukanta, Ulakanda, Coorgee, Koorjee, Wirtiree
scientific namen	Caloprymnus campestris, Bettongia campestris, Hypsiprymnus campestris
original range	Central Australia
time of extinction	1935
causes of extinction	introduced animals, habitat loss, hunting
IUCN status	extinct

The rediscovery of the desert rat-kangaroo (1931)

In 1931 everything changed. After the end of a long drought, the Australian mammalogist Hedley Herbert Finlayson succeeded in the rediscovery of the desert rat-kangaroo. In a remote, hostile landscape of sand hills and boulder fields in northeastern South Australia, between the Diamantina and Cooper Creek rivers, he came across a population of the supposedly extinct species.

Finlayson was astonished to find that the animal had been able to remain hidden in this extreme environment for decades. Although the population was small, the recovery of vegetation after the drought also seemed to benefit the desert rat-kangaroo. During his expedition he was able to observe 17 animals and collect twelve specimens in different developmental stages. His aim was to document the species and its way of life comprehensively in order to learn more about this enigmatic marsupial.

Despite the scientific breakthrough, however, some questions remained unanswered—especially the exact origin of the specimens that George Grey had sent to the British Museum in 1843. Finlayson returned to the region several times in the following years, but the desert rat-kangaroo disappeared again without a trace.

Between 1932 and 1935, a few individuals were captured in the Tirari Desert in northeastern South Australia—possibly the last of their species. According to the IUCN, the last confirmed sighting dates from 1935 near Ooroowilanie, east of Lake Eyre.

The forgotten rediscovery—a specimen from 1902

Was Finlayson’s rediscovery actually the first? Decades later it turned out that the desert rat-kangaroo had been found much earlier—and in a different location.

In September 2018, zoologist Mark Eldridge examined the only known specimen of a desert rat-kangaroo in the collection of the Australian Museum. He made a surprising discovery: the animal did not come from Finlayson’s discovery area, but had already been collected by the British naturalist Henry James Hillier at Lake Killalpaninna between 1902 and 1905—a full 26 years before the supposed rediscovery.

Hillier, an avid collector and then an English teacher at a mission school, sent numerous samples to museums in Australia and England. The specimen’s original registration mark bore the entry “H.J. Hillier, Esq.” and the location “Killipanima, E. Lake Eyre, S. Australia”—an incorrect spelling of Killalpaninna, a former Lutheran mission.

This finding had far-reaching consequences: first, the range of the desert rat-kangaroo was larger than previously assumed; second, it had already been rediscovered long before 1931—but this went unnoticed at the time.

Range and habitat of the desert rat-kangaroo

The exact location of the discovery of the first desert rat-kangaroos that George Grey sent to England is not known. However, John Gould, who received the specimens for the first scientific description, noted the area of ​​origin as “the stony and sandy plains in the interior of South Australia, which are partly covered with bushes”.

The desert rat-kangaroo inhabited one of the driest and most inhospitable regions of Australia. Its range was comparatively small, extending across the Lake Eyre basin in northern South Australia and parts of southwest Queensland. It may have reached as far as the neighboring Northern Territory, but there is no clear evidence of this.

His habitat consisted of extremely dry desert ecosystems with only sparse vegetation. The desert rat-kangaroo primarily inhabited loamy plains, sand dunes and boulder fields—barren landscapes with strong Temperature fluctuations between hot days and cold nights. These areas are characterized by salt bushes, small trees and resilient shrubs that are adapted to the hostile conditions.

It is interesting that the scientific name already refers to the habitat of this species: the species name campestris means “living in the field” or “belonging to the steppe” and aptly describes the dry, open habitat of the desert rat-kangaroo.

On the biology and behavior of the desert rat-kangaroo

Little is known about the biology and behavior of the desert rat-kangaroo. Almost everything we know about this species today comes from Hedley Herbert Finlayson’s notes, which he made between 1931 and 1935.

The desert rat-kangaroo was small and delicate, with long hind legs and soft, sand-colored fur that gave it a excellent camouflage in the dry, desert-like landscapes of its habitat. What was noticeable was the thin hair on his chest, which gave him his German name.

Finlayson observed that the desert rat-kangaroo was probably nocturnal in order to avoid the intense daytime heat. Unlike many other small mammals of the arid zone, it did not live in caves or burrows, but sought shelter under sparse shrubs. It dug shallow hollows in the ground, which it lined with leaves and grasses. These simple nests were often placed under shrubs and covered with twigs and blades of grass to provide additional protection.

Its habitat in the Lake Eyre basin was characterized by long dry seasons, only occasionally interrupted by rainfall. The desert rat-kangaroo probably relied on absorbing moisture directly from food, as water sources were rare in its range.

There is hardly any reliable information about the reproduction of the species. Like other rat kangaroos, the species probably brought a single young animal into the world, which initially grew in the mother’s pouch. It is possible that, similar to related species, the desert rat-kangaroo had multiple reproductive cycles per year, depending on environmental conditions.

Although Finlayson’s records provide only limited information, they show that the desert rat-kangaroo was exceptionally well adapted to the extreme conditions of its habitat. But even this specialization could not protect the species from profound environmental changes and the threat posed by introduced predators…

On the extinction of the desert rat-kangaroos

The Australian biologist Tim Flannery stated in Australia’s Vanishing Mammals (1990) that the desert rat-kangaroo probably never had a particularly large population. Although the species was still considered stable in the 1930s, it abruptly collapsed with the next drought period in 1935—and disappeared for good.

The IUCN officially declared the desert rat-kangaroo extinct in 1994 and attributes its decline primarily to the threat posed by introduced predators. Red foxes (Vulpes vulpes) and feral domestic cats (Felis catus), which spread in Australia from the late 19th century onward, posed a serious threat. Their high reproductive rate and adaptability allowed them to hunt the desert rat-kangaroo almost unhindered in its open, vegetation-poor habitat.

In addition, the species may have competed for food with introduced rabbits and hares, although its specialized diet may have limited this pressure. Far more serious, however, was the change in its habitat caused by intensive grazing by cattle and sheep. These livestock stripped the already sparse vegetation bare and compacted the soil, making natural regeneration of the plant life much more difficult.

Hunting of the desert rat-kangaroo may also have contributed to its extinction. Indigenous communities used the animals as a food source, but on a sustainable scale. Under the harsher environmental conditions caused by drought, invasive predators and habitat loss, however, even this limited use may have accelerated the population’s final collapse.

The desert rat-kangaroo is not the only extinct rat-kangaroo species. The Nullarbor dwarf bettong (Bettongia pusilla), the desert bettong (Bettongia anhydra) and the broad-faced potoroo are also now considered extinct.

Numerous sightings: Is the desert rat-kangaroo really extinct?

Although no reliable evidence has existed since 1935, there were repeated unconfirmed sighting reports in the following decades. Especially in the 1950s and 1970s, individual animals were reportedly seen in Queensland after rainy periods. Fresh remains were also discovered in caves in the 1980s, raising doubts about the species’ final extinction.

Between 1957 and 1988, researchers Steve G. Carr and Anthony C. Robinson documented a total of 13 unconfirmed sightings, which were published in the South Australian Naturalist (1997). After that, there were only two relevant observations: in August 1993, an animal was reportedly flushed in daylight near Goyder Lagoon, north of the 1931 discovery site. The second sighting occurred at night in May 2011 at Peake Station, a remote cattle station on the Oodnadatta Track in northern South Australia.

The 2011 sighting received particular attention because the observed animal was later compared with museum specimens and identified as a possible desert rat-kangaroo. However, a follow-up survey in August 2011 produced no clear results. Although researchers found an old nest resembling the known nest structures of rat-kangaroos, as well as small kangaroo-like droppings and footprints near a waterhole, the subsequent DNA analysis of the feces produced no usable results. Analyses of dingo and cat fecal samples from the region also provided no evidence of the desert rat-kangaroo. The sighting therefore could not be confirmed, but researchers Tony Robinson and Tiana Forrest considered it possible in their study (2012) that a small population might still exist:

“The possibility exists that a small population of Caloprymnus, which is generally considered extinct in its former range in the Lake Eyre Basin, existed in this area in May 2011.”

A possible sighting of the Desert Rat-kangaroo or Oolacunta (Caloprymnus campestris) on the Peake Station, South Australia. The South American Naturalist 86 (2). 2012. T. Robinson, T. Forrest.

The big search operation of 2018/19

Despite the large number of sighting reports, scientifically robust evidence for the species’ survival was still lacking. To finally gain clarity, the most extensive search for the desert rat-kangaroo to date was carried out in 2018 and 2019. Researchers specifically investigated former sites from the 1930s as well as areas with more recent sighting reports. State-of-the-art methods were used: more than 6,000 camera-trap nights, analysis of 536 fecal samples from predators (dingoes, foxes, cats), and 226 kilometers of spotlight searches.

But despite all efforts, not a single piece of evidence for the existence of the desert rat-kangaroo was found. However, the researchers emphasize that the vastness and inaccessibility of the potential range makes a definitive statement difficult:

“Due to the vastness and inaccessibility of the area considered the former range of Caloprymnus campestris, we do not see our result as definitive proof of the extinction of this little-researched animal. Rather, our work should serve as a starting point for future investigations.”

A search for the desert rat-kangaroo or ngudlukanta (Caloprymnus campestris) in north-eastern South Australia. Australian Mammalogy 44 (2). 2021. K. Vernes, S. M. Jackson, T. F. & K. Elliott, S. G. Carr.

Hope for rediscovery?

The sighting in 2011 and the intensive search in 2018/19 show how difficult it is to make a final statement about the species’ fate. The rediscovery of other marsupials thought to have disappeared shows that there is still hope. Gilbert’s potoroo (Potorous gilbertii) was rediscovered after 120 years, and the long-footed potoroo (Potorous longipes), a species only discovered in 1967, also eluded science for a long time.

The zoologist Ronald Nowak also speculated in Walker’s Marsupials of the World (2005) that a small remnant population of the desert rat-kangaroo may have survived—hidden in one of Australia’s most remote and unexplored regions.

Study on feeding habits raises hope for the existence of the desert rat-kangaroo

Although the last known specimen of the desert rat-kangaroo was collected in 1935 and the species was officially considered extinct in 1994, rediscovery remains possible. The remote, difficult-to-access desert regions in central Australia offer numerous refuges for small, nocturnal animals. In addition, there are repeated reports of sightings of an animal matching the description of the desert rat-kangaroo.

A recent study by D. Rex Mitchell and his team (2025) provides new findings that could make targeted searches for the desert rat-kangaroo easier. Using biomechanical analyses of the skull, the researchers reconstructed the species’ diet. Studies of the skull’s load-bearing capacity during chewing provide clues as to the regions where the animal may most likely have survived.

The results contradict previous assumptions: the powerful skull of the desert rat-kangaroo was apparently not —as long assumed—specialized for chewing particularly hard food. Previous theories that it fed on seeds and twigs have been refuted. Instead, the analyzes suggest that the species primarily ate softer plant parts such as leaves and possibly roots. This finding could make the search much easier: regions in which these plant species still occur today should be investigated as a priority. In particular, the Lake Eyre basin in the far northeast of South Australia and adjacent areas in Queensland, where there have been unconfirmed sightings in the past, are considered promising search areas.

The remote and inaccessible nature of its habitat may explain why the desert rat-kangaroo remained undiscovered for decades. Its already low population density may have made finding it even more difficult. Since parts of its former range remain little studied to this day, the possibility remains that still-undiscovered populations exist in remote regions of the Australian outback.

Steppe kangaroo-rat: kangaroo or rat?

Rat-kangaroos like the desert rat-kangaroo are close relatives of the actual kangaroos. They move in the same way, have short front legs and strong, long hind legs and have similarly colored fur in shades of brown to gray.

The biggest difference between rat kangaroos and true kangaroos is their diet. While kangaroos feed mainly on grasses and herbs, the food intake of rat kangaroos is more diverse. Some species are omnivores and eat not only tubers, seeds and mushrooms, but also insects, worms and larvae. The current study (Mitchell et al., 2025) suggests that the desert rat-kangaroo had a more specialized diet. Contrary to previous assumptions, it did not eat hard seeds or twigs, but primarily softer plant parts such as leaves and possibly roots. This meant that it ate a purely plant-based diet, but in a different way than the grass-eating kangaroos. Rat kangaroos meet their fluid needs with food. Rat-kangaroos are optimally adapted to survive in the Australian desert, where plants grow sparsely and water sources are rare.

A confusing name

In addition to the rat kangaroos, there are also kangaroo rats (Dipodomys), but they belong to a completely different group of animals. These rodents from the family of pocket mice (Heteromyidae) are native to Mexico and the USA and have nothing to do with Australian marsupials. It seems all the more strange that the zoologist Alfred Brehm once called the desert rat-kangaroo a “steppe kangaroo-rat.”.

In fact, one species of kangaroo rat is also extinct: Dipodomys microps russeolus, a subspecies of the thick-tailed kangaroo rat that disappeared in the 1940s. But despite the name, the desert rat-kangaroo and the kangaroo rat have nothing in common—except perhaps the ability to survive in extremely dry areas.

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Sources

• Carr, S.G., Robinson, A.C. (1997). The present status and distribution of the Desert Rat-kangaroo Caloprymnus campestris (Marsupialia: Potoroidae). South Australian Naturalist 72. pp. 4-27.
• Finlayson, H.H. (1932). Rediscovery of Caloprymnus campestris (Marsupialia). Nature 129: 871. 
• Flannery, T. (1990). Australia’s Vanishing Mammals.
• Gould, J. (1843). On a new species of Kangaroo Rat. Proceedings of the Zoological Society of London 1843, p. 81.
• Mitchell, D. R., Wroe, S., Martin, M., & Weisbecker, V. (2025). Testing hypotheses of skull function with comparative finite element analysis: three methods reveal contrasting results. Journal of Experimental Biology, jeb.249747.
• Robinson, T., & Forrest, T. (2012). A possible sighting of the Desert Rat-kangaroo or Oolacunta (Caloprymnus campestris) on the Peake Station, South Australia. The South Australian Naturalist, 86(2), pp. 63-75.
• Vernes, K., Ingleby, S., & Eldridge, M. D. B. (2020). An overlooked, early record of the desert rat-kangaroo (Caloprymnus campestris) from Lake Killalpaninna, South Australia. Australian Mammalogy, 42(2), pp. 223-225.