The golden bandicoot (Isoodon auratus; Yolngu: Wan'kurra) is a short-nosed bandicoot found in northern Australia. It is the smallest of its genus, and is distinguished from the brown bandicoots by its golden colouring and much smaller size.
It was once found throughout much of northern, central and western Australia, into south-western New South Wales, but it is now restricted to a few areas in Western Australia (WA) and the Northern Territory (NT). The I. auratus auratus subspecies, also known as the golden bandicoot (mainland), is found in the Kimberley region of WA, and on three of the Wessel Islands, NT: Marchinbar, Raragala, and Guluwuru Islands. Another subspecies, I. auratus barrowensis or golden bandicoot (Barrow Island), is found on Augustus, Barrow and Middle Islands off Western Australia (I. auratus barrowensis). the classification into subspecies is debated; however the whole species is classed as vulnerable species.
Taxonomy
Earlier studies have suggested that the golden bandicoot (I. auratus) is closely related to the southern brown bandicoot (I. obesulus), and they may in fact be the same species. Zenger et al. (2005) posited that mitochondrial DNA evidence suggested that these two species ought to be grouped into one species with three distinct subspecies, I. obesulus obesulus, I. o. peninsulae, and I. o. fusciventer. I. auratus would be included in the I. o. fusciventer subspecies.
A third subspecies, I. a. arnhemensis has been recorded in Arnhem Land, NT, in the past, from the 1930s to 1980s, but this is now thought to be I. a. auratus.
I. obesulus and I. auratus appear to have been allopatric ever since the Pleistocene. , the IUCN determines that I. auratus is a single species with no subspecies, while Isoodon peninsulae is a separate species.
Distribution
Range
The golden bandicoot was once found across most of northern, central and western Australia, as far as south-western New South Wales to the east. Some had also been sighted NSW/SA border, However, numbers declined sharply within a few decades after European settlement of Australia, and was gone from the central deserts by around 1950. By 1983 the only populations on the mainland remained in the Prince Regent National Park in the Kimberley region. It occurs in stable numbers on Barrow, Middle, and Augustus Islands, and by 1995 it was known to live in the Yampi Peninsula in northern Kimberley, as well as and Marchinbar Island in the Northern Territory.
The subspecies I. a. arnhemensis was recorded in Arnhem Land from the 1930s to 1980s, but this is now thought to be I. a. auratus. After the population was restricted to Marchinbar Island, groups were translocated and populations have been established on Raragala and Guluwuru Islands, also in the Wessel chain.
The largest golden bandicoot population lives on Barrow Island, because no cats or foxes have been introduced to the island, and other populations exist on Middle, Marchinbar, Augustus Islands. Small populations on mainland Australia are located in the Northern Territory and Western Australia. The golden bandicoot once lived all throughout Central Australia, but by 1992 it had been reduced to a small area in northwest Kimberly and Arnhem Land. In 2000, it was assumed that the species was extinct on the mainland.
It is also present in the Charnley River–Artesian Range Wildlife Sanctuary in the Kimberley.
Habitat
The golden bandicoot lives in spinifex and tussock grasslands, and it used to be widely distributed in arid deserts and the surrounding semi-arid areas as well as tropical forests and woodlands. In Northern Kimberley, it is found along the margins of rainforests lined with sandstone, and in the Yampi Peninsula it inhabits eucalypt woodlands. On Augustus and Marchinbar Islands it lives amongst sandstone in hummock grassland and heath or eucalypt woodlands, and on Barrow and Middle Islands it is found in grasslands and coastal shrub. Its range once included the Gibson, Great Sandy, Great Victoria, Little Sandy, and Tanami deserts. It is believed that the golden bandicoot disappeared from the deserts between the 1940s and 1960s.
Population numbers
Individuals have a home range between , and the largest golden bandicoot population is on Barrow Island with about 20,000 individuals. In fact, it is the most common mammal on the island. On Middle Island it is estimated that there are about 1,000 individuals, and on Marchinbar Island there are roughly 1,400 individuals. On mainland Australia, populations are sparse, and most population declines have occurred there.