Broad-faced Potoroo

Of hare-kangaroos, rat-kangaroos and true kangaroos

The Australian broad-faced potoroo is not a kangaroo (Macropodidae) as we know it, but at family level a rat-kangaroo (Potoroidae) and at genus level a potoroo (Potorous). It is closely related to the true kangaroos, but differs from them in several respects. The rat-kangaroo family comprises four genera with twelve species, four of which have become extinct in modern times: the broad-faced potoroo, the desert rat-kangaroo, the Nullarbor bettong (Bettongia pusilla) and the desert bettong (Bettongia anhydra).

In its body shape, with long hind legs and short forelegs, the broad-faced potoroo resembled the true kangaroos, but it was hardly larger than a guinea pig and therefore much smaller than most true kangaroos: The marsupial’s head-body length was around 30 centimeters, plus a tail almost 18 centimeters long. It weighed only about 800 grams.

The English ornithologist John Gould wrote in 1844 in the scientific first description of Hypsiprymnus platyops that its skull was “extremely broad”. The broad-faced potoroo owes its common name to this feature. The short and blunt nose is also unusual for the genus of potoroos and is otherwise more associated with the rufous rat-kangaroo (Aepyprymnus rufescens) and the extinct desert bettong.

Broad-faced potoroo – fact sheet

alternative names	Broad-faced rat-kangaroo, Broad-toothed potoroo, Moda, Mor-da, Warrack , Moort, Mort
scientific names	Potorous platyops, Hypsiprymnus platyops, Potorous morgani, Potorous platyops morgani
original range	Australia
time of extinction	1875
causes of extinction	habitat loss, absence of Aboriginal fire-clearing, introduced animals, animal diseases
IUCN status	extinct

On the discovery of the broad-faced potoroo

For a long time, little was known about the life of the naturalist John Gilbert, who was probably English and was born between 1810 and 1815. Only when several letters and diaries appeared in 1938 in the estate of the German zoologist and botanist Ludwig Leichhardt was it possible to form a picture of Gilbert.

When Gilbert worked as a taxidermist at the Zoological Society of London, he met the somewhat older John Gould, after which the two initially traveled together to Australia as research travelers in 1838. In the following years, Gilbert collected natural history study specimens for Gould’s publications and made countless, in some cases unique, notes on birds. He is also considered the first Western researcher who was able to make observations on the paradise parrot (Psephotus pulcherrimus), which became extinct in 1928.

By the time he was killed by a thrown Aboriginal spear in 1845, Gilbert had collected 432 bird skins and 318 mammal specimens; among them were 36 new bird species and 22 new mammal species—many of which Gould described scientifically. The broad-faced potoroo was one of them: Gilbert collected the holotype of the broad-faced potoroo in 1842 on the southwest coast of the Australian state of Western Australia near King George Sound, or in the thickets around Lake Walymouring. Two years later, Gould described the new taxon.

Broad-faced potoroos: Rare even when discovered

Most early reports on the broad-faced potoroo already state that it was a rare species. This remark also fits the small number of specimens in today’s mammal collections in museums. In addition, the English zoologist George Masters, who worked in Australia in the 19th century, found only five broad-faced potoroos in the 1860s, which is quite few compared with other species he collected. It is said that between 1874 and 1875 the last five broad-faced potoroos were killed and sold to the National Museum in Victoria. The World Conservation Union IUCN also gives 1875 as the year in which the species was last recorded.

At the beginning of the 20th century, hope briefly flared up again that broad-faced potoroos might still exist when London Zoo acquired a supposed specimen from the Margaret River region in 1908. However, it quickly turned out to be merely a young quokka or short-tailed scrub wallaby (Setonix brachyurus).

Why did the broad-faced potoroo become extinct?

As with the eastern hare-wallaby, which disappeared around 1890 and was endemic to southeastern Australia, many factors probably contributed to the extinction of the species in the case of the broad-faced potoroo. The IUCN also lists five causes that are said to have interacted: feral cats, an exotic disease, uncontrolled fire-clearing, habitat degradation through grazing of grassland by livestock, as well as habitat loss and fragmentation.

Different scientists have different views on what should ultimately be regarded as the main cause. In his 1910 paper in the Proceedings of the Zoological Society of London, mammalogist Guy C. Shortridge assumed that stray cats and ecological changes such as bushfires caused the decline of the broad-faced potoroo. As far as stray cats are concerned, various studies indicate that they were present throughout the broad-faced potoroo’s entire range. It would not be the first Australian species whose population was reduced by cats or other invasive species targeting small and medium-sized mammals. The long tail of the broad-faced potoroos was also certainly especially fascinating to cats.

In Historical Perspectives of the Ecology of some conspicuous vertebrate Species in south-west Western Australia (2008), biologist Ian Abbott assumes that the broad-faced potoroo disappeared mainly because of an animal disease that entered its habitat. In Ausgestorbene Tiere (2021), Bernhard Kegel suspects “hunting, invasive species (cats), habitat destruction” as the main causes. And according to David Day in The Doomsday Book of Animals (1983), the Indigenous Australians are said to have blamed stray cats and bushfires caused by colonists for the extinction of the species.

Most scientists doubt assumptions that red foxes (Vulpes vulpes) introduced to Australia or European rabbits could have wiped out the broad-faced potoroo. According to the IUCN, the marsupial was already extinct when the red fox reached Western Australia, and when the rabbits reached the former range of the broad-faced potoroos, population numbers were already declining, according to biologist Andrew W. Claridge in Bettongs, Potoroos, and the Musky Rat-kangaroo (2007).

Little is known about its way of life

Naturalists found all living broad-faced potoroos in the mid-19th century in the southwest of the state of Western Australia. However, subfossil remains indicate, according to an Australian study (2012) by paleontologist Matthew C. McDowell, that the species must once have had a much larger range. This extended from the southern edge of the Nullarbor Desert in Western Australia across Kangaroo Island in South Australia to the lower reaches of the Murray River in southeastern Australia. The broad-faced potoroo was therefore originally distributed in the semiarid coastal regions of southwestern Australia.

The Aboriginal people in the Margaret River area, who called the broad-faced potoroo Mor-da or Warrack, described the marsupials as slow-moving and easy to catch. Otherwise, almost nothing is known about the broad-faced potoroo’s habits. It can be assumed, however, that they matched those of other rat-kangaroos. Unlike the true kangaroos, which feed on plants, they were probably omnivores. This means they probably ate mainly fungi, insects and roots.

There are also only sparse records of the broad-faced potoroo’s habitat. One informant told John Gilbert, for example, that the marsupial species could be found in thickets surrounding salt lagoons in the interior.

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