|C. yirratji specimen, Grande galerie de l'évolution|
|Historic pig-footed bandicoot range in orange|
The pig-footed bandicoots (genus Chaeropus) are two very similar species of small marsupials that inhabited the arid and semi-arid plains of Australia. The distribution range of the genus was later reduced to an inland desert region, where it was last recorded in the 1950s; it is now presumed to be extinct.
This genus was previously placed in the family Peramelidae, along with the bilbies, as the subfamily Chaeropodinae by McKenna and Bell (1997). However, its form is quite distinct from the Peramelidae and bilbies, and recent molecular evidence supports this distinction. It is believed to be the sister group of the rest of the Peramelmorphia and has been assigned to its own family Chaeropodidae.
Until 2019, both species were grouped under C. ecaudatus as the pig-footed bandicoot; however, a 2019 study split the genus into two species: the northern pig-footed bandicoot (C. yirratji) and the southern pig-footed bandicoot (C. ecaudatus).
The pig-footed bandicoots had a body size of 23–26 cm and a 10–15 cm long tail. In form, they were almost bilby-like on first sight, having long, slender limbs, large, pointed ears, and a long tail. On closer examination, however, it became apparent that the pig-footed bandicoots were very unusual for marsupials. The forefeet had two functional toes with hooves, rather similar to a pig or deer; this is possibly due to juveniles being deposited in the pouch through external stalks, thus relieving them of using the forelimbs while as joeys. The hind feet had an enlarged fourth toe with a heavy claw shaped like a tiny horse's hoof, with the other toes being vestigial:only the fused second and third toes being useful, and that not for locomotion but for grooming.
They had broad heads, and a long yet slender snout. Their fur was coarse and straight, but not spiny. In color they varied from grizzled grey through fawn to orange-brown, the belly and underparts were white with the fur on the ears being of chestnut color.
The genus had five pairs of upper and three pairs of lower incisor teeth; the tooth shape differed between the two species. The females of the genus had eight nipples and the opening of the pouch was faced backwards, not forwards as is the case with kangaroos. According to Indigenous Australian trackers, the pig-footed bandicoot was known as "Landwang" and "Tubaija" in their culture.
Distribution and habitat
The pig-footed bandicoot was native to western New South Wales and Victoria, the southern part of the Northern Territory as well as South Australia and Western Australia. C. ecaudatus populated arid areas ranging from southern Australia to western Australia, while C. yirratji populated sandy environments from western Australia to the deserts in central Australia. They inhabited a wide range of habitat types: from grassy woodland and grassland plains to the spinifex country and arid flats of central Australia. Despite its wide range, the genus had a sparse distribution and was never abundant.
Behaviour and ecology
Few scientists had the opportunity to observe a live pig-footed bandicoot, with the only existing account of its behaviour suggesting that it moved "like a broken-down hack in a canter, apparently dragging the hind quarters after it". This is contradicted by the Aboriginal people of central Australia, who knew it well and reported that if disturbed, it was capable of running with considerable speed by breaking into a smooth, galloping sprint.
They were solitary, nocturnal animals that would sleep in their shelter during the day and emerge in the evening to feed, using its keen sense of smell to find food. Depending on the habitat, pig-footed bandicoots used a variety of shelters to hide from predators and for sleeping. In wooded areas and grasslands these ranged from hollow logs and nests made out of grass, while in arid treeless country this animal used to dig short, straight burrows with a nest at the end.
From surviving eyewitness reports and analyses of gut contents, dentition, and gut structure of museum specimens, it appears that pig-footed bandicoots were the most herbivorous of bandicoots; although captive specimens were fond of meat and Aborigines reported that they ate grasshoppers, ants and termites, the bulk of their diet was almost certainly leaves, roots and grasses. In captivity it was observed that they drank "a good deal of water".
Tim Flannery suggests that breeding occurred between May and June and that twins may have been the norm for this species. From the size of its pouch and comparison with other marsupials of this size, it can be inferred that pig-footed bandicoots did not carry more than four young per litter.
According to Indigenous Australian oral tradition, pig-footed bandicoots were rare even before the arrival of Europeans on the continent and were in a serious decline even as it first came to scientific notice in the middle years of the 19th century. Two specimens of pig-footed bandicoot were obtained by local people in 1857 for Gerard Krefft, who accompanied the Blandowski Expedition. Despite the trouble taken in gaining living specimens, Krefft recorded his observations with an apology for eating one of them. Only a handful of specimens were collected through the second part of the 19th century, mostly from northwestern Victoria, but also from arid country in South Australia, Western Australia, and the Northern Territory. By the start of the 20th century, they had become extinct in Victoria and the south-west of Western Australia. The last certain specimen was collected in 1901. By 1945, C. ecaudatus was extinct, having vanished from South Australia, and C. yirratji was reported to be limited to "a slight foothold in central Australia". Nevertheless, Aboriginal people report that C. yirratji survived as late as the 1950s in the Gibson Desert and the Great Sandy Desert of Western Australia.
The cause of the extinction remains uncertain: neither of the two most destructive introduced exterminator species, the fox and the rabbit, had yet arrived in south-west Western Australia when the pig-footed bandicoots disappeared from that area. Feral cats were already common, which may offer an explanation; it is perhaps more likely that the decline was caused by a double habitat change. Firstly, the end of many thousands of years of Aboriginal burning which, being confined to a patchwork of small areas at any one time, had ensured both fresh new growth in the recently burnt areas and adjacent older growth for shelter and as a base for recolonisation. However, Australia's Aboriginal population had declined by around 90% during the 19th century, largely because of the introduction of European diseases, and the remaining Aborigines were often no longer permitted to carry on their traditional land-management and hunting practices. Secondly, following on the heels of the near-extermination of the Aborigines, came the introduction of vast numbers of sheep and cattle, leading to significant changes in soil structure, plant growth, and food availability.
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