southern brown bandicoot

George Shaw described the species as Didelphis obesula in 1797. While some authorities list as few as two subspecies (I. o. obesulus and I. o. nauticus), there are currently five recognised species:

• Isoodon obesulus nauticus - restricted to the Nuyts Archipelago
• Isoodon obesulus obesulus - NSW, Victoria, SA
• Isoodon obesulus peninsulae - Cape York Peninsula
• Isoodon obesulus affinus - Tasmania and Bass Strait Islands
• Isoodon obesulus fusciventer- southwest WA. This subspecies was elevated to species in 2018.{{Cite journal |last1=Travouillon |first1=Kenny J. |last2=Phillips |first2=Matthew J. |date=2018-02-07 |title=Total evidence analysis of the phylogenetic relationships of bandicoots and bilbies (Marsupialia: Peramelemorphia): reassessment of two species and description of a new species |url=https://pubmed.ncbi.nlm.nih.gov/29690027/ |journal=Zootaxa |volume=4378 |issue=2 |pages=224–256 |doi=10.11646/zootaxa.4378.2.3 |issn=1175-5334 |pmid=29690027}}

File:A hand-book to the marsupialia and monotremata (Plate XXIII) (6008902402).jpg

Southern brown bandicoots have a stocky body with a short snout and short, rounded ears. They show sexual dimorphism, with females being smaller than males. On average, males measure {{convert|50|cm|abbr=on}} in total length, and weigh up to {{convert|1.2|kg|abbr=on}}, while females measure {{convert|40|cm|abbr=on}} and weigh no more than {{convert|1|kg|abbr=on}}. They have coarse, bristly hair that is grizzled and coloured a dark greyish to yellowish brown, with the undersides a creamy-white or yellowish grey. The tail is relatively short, measuring about {{convert|13|cm|abbr=on}} in length, and is brown above and white below.

There are five toes on each foot, although, as in many other marsupials, they are syndactylous, with the second and third toes of the hind foot are fused along almost their entire length. The toes end in sturdy claws, except for the first digits of the fore feet and the fifth digits of the hind feet, which are tiny and vestigial. The pouch in females opens to the rear, and contains eight teats arranged in a partial circle.

File:Southern_Brown_Bandicoot_juvenile.jpg

Once common throughout many parts of coastal Australia, today southern brown bandicoots have a more limited distribution. An isolated population exists at the north-eastern part of the Cape York Peninsula in Queensland, but all other surviving animals are found in the southern half of the country. In New South Wales they are considered rare, and are primarily restricted to the extreme south-east of the state and to two national parks north of Sydney. In Victoria, they are more common, being found along the whole length of the coast and at up to {{convert|1000|m|abbr=on}} in the Grampian and Dandenong mountains.

In South Australia, they inhabit the Eyre and Fleurieu peninsulas, the extreme southeast, and Kangaroo Island.{{cite journal | last = Paull | first = D. | date = 1995 | title = The distribution of the southern brown bandicoot (Isoodon obesulus obesulus) in South Australia | journal = Wildlife Research | volume = 22 | issue = 5 | pages = 585–599 | doi = 10.1071/WR9950585}} Isolated and increasingly restricted populations are known from south-western Western Australia. However, southern brown bandicoots are most common in Tasmania, where they are found across almost the entire island. They are also currently found on Inner Sister Island but have been extirpated from many other small Tasmanian islands where they once lived.

Within these regions, southern brown bandicoots inhabit open forest, scrub, and heathland, especially where there is extensive ground cover by shrubs or mat-rushes.{{cite journal | last1 = Keiper | first1 = P. | last2 = Johnson | first2 = C.N. | date = June 2004 | title = Diet and habitat preference of the Cape York short-nosed bandicoot (Isoodon obesulus peninsulae) in north-east Queensland | journal = Wildlife Research | volume = 31 | issue = 3 | pages = 259–265 | doi = 10.1071/WR02030}} I. o. obesulus has shown a preference for the margins of artificial waterways over drier habitats.{{cite journal |last1=Bruce |first1=Matthew J. |last2=Bryant |first2=David B. |last3= Kohout|first3=Michele|last4=Macak |first4=Phoebe V.|last5=Batpurev |first5=Khorloo|last6= Sinclair |first6=Steve J.|date= 26 July 2022 |title=Southern brown bandicoots, Isoodon obesulus obesulus, occupy the margins of artificial waterways, in preference to bushland remnants or roadside vegetation. |url= |journal=Wildlife Research |volume= |issue= |pages= |doi=10.1071/WR21122 |s2cid=251113986 |access-date=}}

Southern brown bandicoots are nocturnal and omnivorous, feeding on insects, spiders, worms, plant roots, ferns, and fungi. They spend very little time drinking, being able to obtain sufficient water from their diet alone.{{cite journal | last = Larcombe | first = A.N. | date = 2003 | title = Activity rhythms of southern brown bandicoots Isoodon obesulus (Marsupialia: Peramelidae) in captivity | journal = Australian Mammalogy | volume = 25 | issue = 1 | pages = 81–86 | doi = 10.1071/AM03081| doi-access = free }} Although their native predators include barn owls, tiger snakes, and quolls, the bandicoots do not avoid the odour of these animals, which may make them vulnerable to predation.{{cite journal | last1 = Mella | first1 = V.S.A. | last2 = Cooper |first2 = C.E. | last3 = Davies | first3 = S.J.J.F. | date = December 2010 | title = Predator odour does not influence trappability of southern brown bandicoots (Isoodon obesulus) and common brushtail possums (Trichosurus vulpecula) | journal = Australian Journal of Zoology| volume = 58 | issue = 5 | pages = 267–272 | doi = 10.1071/ZO10049}} They do, however, typically avoid one another, living solitary lives in non-overlapping home ranges that typically vary from {{convert|1|to|5|ha}}, depending on the local conditions. If males encounter one another, the more dominant individual leaps onto the back of the other, scratching with its claws. Because the skin of bandicoots is unusually thick, this results in hair loss, but little permanent injury to the defeated male.

They spend much of the night searching for food, which the detect primarily by scent, sniffing the ground before digging into with their claws. They pursue any prey that escapes, holding it down with their forepaws as they consume it. The digging behaviour is considered a critical component in the maintenance of the ecosystems in which they live. It is estimated that a single bandicoot displaces around 3.9 tonnes of soil each year.{{cite journal |last1=Valentine |first1=Leonie E |last2=Anderson |first2=Hannah |last3=Hardy |first3=Giles E |last4=Fleming |first4=Patricia A |date= 22 May 2013|title=Foraging activity by the southern brown bandicoot (Isoodon obesulus) as a mechanism for soil turnover |journal=Australian Journal of Zoology |volume=60 |issue=6 |pages=419–423 |doi=10.1071/ZO13030 |s2cid=85392260 |url=https://api.research-repository.uwa.edu.au/ws/files/35085109/Valentine_et_al_2013_Forgaing_activity_by_the.pdf }} They spend the day sleeping in well-concealed nests of shredded vegetation. Both sexes possess scent glands between the ears that are apparently used in intra-species communication and become enlarged during the breeding season.{{cite journal | last = Stoddard |first = D.M. | date = 1980 | title = Observations on the structure and function of cephalic skin glands in bandicoots (Marsupialia: Peramelidae) | journal = Australian Journal of Zoology | volume = 28 | issue = 1 | pages = 33–41 | doi = 10.1071/ZO9800033}}

The Southern brown bandicoot is a host of the Acanthocephalan intestinal parasite Australiformis semoni.{{Cite journal |doi = 10.2307/3282769|pmid = 2926590|jstor = 3282769|title = Australiformis semoni (Linstow, 1898) n. Gen., n. Comb. (Acanthocephala: Moniliformidae) from Marsupials of Australia and New Guinea|journal = The Journal of Parasitology|volume = 75|issue = 2|pages = 215–7|year = 1989|last1 = Schmidt|first1 = Gerald D.|last2 = Edmonds|first2 = Stanley J.}}

Reproduction is closely linked to local rainfall pattern, and many brown bandicoots breed all year around, giving birth to up to four litters a year.{{cite book | author = Whitfield, Philip | title = The Simon & Schuster Encyclopedia of Animals | location = New York | publisher = Marshall Editions Development Limited | year = 1998 | page = 24}} Gestation lasts less than fifteen days, and perhaps as few as twelve, and typically results in the birth of two or three young, although litters of up to five have been reported; larger mothers tend to give birth to larger litters.{{cite journal | last1 = Stoddart |first1 = D.M. |last2 = Braithwaite |first2 = R.W. | date = 1979 | title = A strategy for utilization of heathland habitat by the brown bandicoot (Isoodon obesulus; Marsupialia, Peramelidae) | journal = Journal of Animal Ecology | volume = 48 | issue = 1 | pages = 165–179 | doi = 10.2307/4107| jstor = 4107 }}

The young weigh just {{convert|350|mg|abbr=on}} at birth, remain in the pouch for about the first 53 days of life, and are fully weaned at around 60 days. Growth and maturation is relatively rapid among marsupials, with females becoming sexually mature at four to five months of age, and males at six or seven months. Lifespan in the wild is probably no more than four years.

The southern brown bandicoot is currently classified as Least Concern by the IUCN. However, populations have declined markedly and become much more fragmented in the time since European expansion on the Australian mainland. In many areas of its range the species is threatened locally, while it may be common where rainfall is high enough and vegetation cover is thick enough. Apart from habitat fragmentation, the species is under pressure from introduced predators such as the red fox and feral cats. It has been reintroduced to some lower rainfall areas where there is protection against cat and fox predation – one such site being Wadderin Sanctuary in the eastern wheatbelt of Western Australia, 300 km east of Perth.

In national assessment, the southern brown bandicoot is currently regarded as Endangered on the mainland as a whole, and Vulnerable in South Australia.{{cite web|url=http://www.naturalresources.sa.gov.au/files/504d2d2b-a558-47b7-b84b-a2ab00c48027/informing-biodiversity-rep.pdf|title=Informing Biodiversity Conservation for the Adelaide and Mount Lofty Ranges Region, South Australia|publisher=Department for Environment and Heritage, Government of South Australia}}

{{Reflist}}

{{Commons category|Isoodon obesulus}}

• [https://www.aussieark.org.au/southern-brown-bandicoot/ The Aussie Southern Brown Bandicoot Ark Conservation Project]

{{Peramelemorphia}}

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Category:Endangered fauna of Australia

Category:Peramelemorphs

Category:Marsupials of Australia

Category:Mammals of Tasmania

Category:Mammals of Western Australia

Category:Mammals of South Australia

Category:Mammals of Queensland

Category:Mammals of Victoria (state)

Category:Mammals described in 1797

Category:Taxa named by George Shaw