There are three main factors that have contributed to the decline of the Numbat: habitat destruction, introduced predators and fire.
The Numbat was widespread throughout the wheatbelt of Western Australia until the early 1960s. However, increased clearing of bush for agriculture saw only small areas of vegetation favoured by the Numbat remain in a system of reserves. The few individuals that survived were isolated in these reserves and such small populations were extremely vulnerable to introduced predators.
Foxes and feral cats introduced to Australia are efficient predators and have had a significant impact on Numbat numbers in the wild. Abandoned domestic dogs and cats are also likely to attack and eat Numbats.
Desert dwelling Aborigines used fire as a tool for hunting, burning small areas of vegetation and creating a mosaic of burnt and unburnt areas. However, when these traditional practices ceased, a single wildfire was able to burn very large areas of bush leaving very little refuge for the Numbat. The combination of introduced predators and large fires saw the end of the Numbat in the desert.