apology for eating one of them. Only a handful of specimens was 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; perhaps more likely, 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. 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. The species was included in historical modelling of a disease outbreak, a theorised epizootic that was the primary cause of mammalian declines, to which the populations of Chaeropus would seem to have been highly susceptible. The sudden demise of these marsupials was noted by Hal Colebatch, writing in 1929 that the disappearance was not the result of direct actions of settlers, but an unexplained consequence of a natural event. The apparent resilience of some mammals at Kellerberrin, which reappeared after a localised collapse, did not include this genus. When modelled as a primary factor in their demise, which has no discernible secondary factors, the population had no