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Isoodon obesulussouthern brown bandicoot

By Kasey Blevins

Geographic Range

The southern brown bandicoot (Isoodon obesulus) is found sporadically throughout the southernmost coastal regions of Australia. Specifically, it is located in the southern tip of Western Australia, the entire coastal region of Victoria extending into New South Wales, as well as a small section of the northernmost cusp of Queensland along the coastline. The southern brown bandicoot has also been observed throughout the island of Tasmania. ("Isoodon obesulus - southern brown bandicoot (Eastern)", 2015; "Isoodon obesulus ssp. obesulus", 2008; "Quenda: Isoodon obesulus (Shaw, 1797)", 2012; "Southern brown bandicoot (Isoodon obesulus) Recovery Plan", 2006)

Habitat

The southern brown bandicoot is primarily found in regions along the ocean, but its habitat is dynamic. Various microbiomes make up the habitat of the southern brown bandicoot throughout Australia and Tasmania. It is commonly found in areas of expansive, dense, swamp-like vegetation and brush (about 0.2-1m tall) near bodies of water such as a lake, stream, or ocean. Also, it can inhabit more inland areas such as forests or scrubland with dense ground vegetation. The different vegetation creates a certain level of protection and ample coverage which provides a natural camouflage from various predators. The elevation of the area where the southern brown bandicoot inhabits varies between islands. On the mainland of Australia, the elevation is between 0-300 meters, and on the island of Tasmania the elevation can vary between 0-600 meters. ("Isoodon obesulus - southern brown bandicoot (Eastern)", 2015; "Isoodon obesulus ssp. obesulus", 2008; "Quenda: Isoodon obesulus (Shaw, 1797)", 2012; "Southern brown bandicoot (Isoodon obesulus) Recovery Plan", 2006; Driessen and Rose, 2015)

  • Range elevation
    0 to 600 m
    0.00 to 1968.50 ft

Physical Description

At birth, neonates weigh between 0.2-0.4 grams and are about 1 cm long but they develop quickly into adults. Males will continuously grow throughout their lifetime and will weigh 500-1850 grams. Females stop growing around 18 to 24 months of age and weigh between 400-1200 grams as adults.

The southern brown bandicoot is a marsupial, with a cumulative head and body length averaging 330 mm in males and 300 mm in females. It has a distinctly long tail, which in males averages 124 mm, and in females 113 mm, accounting for 40% of their body size. However, it is common to see an individual with a noticeably smaller or nonexistent tail. This is a result of fighting between male bandicoots. The southern brown bandicoot has very short, coarse fur that can include a mixture of colors ranging from black and grey to brown and golden yellow. Also, unlike other related species, this bandicoot has extremely small ears that are rounded at the top and face outwards. This species’ snout is much smaller in comparison to its counterparts such as the long-nosed bandicoot (Perameles nasuta). ("Bandicoots", 2006; Driessen and Rose, 2015; "Isoodon obesulus - southern brown bandicoot (Eastern)", 2015; "Quenda: Isoodon obesulus (Shaw, 1797)", 2012)

  • Sexual Dimorphism
  • sexes alike
  • male larger
  • Range mass
    400 to 1850 g
    14.10 to 65.20 oz
  • Range length
    370 to 500 mm
    14.57 to 19.69 in
  • Average basal metabolic rate
    1.238 W
    AnAge

Reproduction

Mating systems of the southern brown bandicoot are not well known. However, there are some key aspects that are known. This species as a whole is polygynandrous, with females acquiring a new partner every time they breed. Breeding occurs on average four times every breeding cycle which occurs from July to December or February depending on the location of the bandicoot. ("Bandicoots", 2006; Birkhead and Moller, 1998)

The southern brown bandicoot has a very rapid reproduction rate aided by a long breeding season. This season spans the months of July to December in Victoria, while extending to February in Tasmania. It is not uncommon for a female to have two to four litters per season depending on how long the season might last that year. Females can carry litters up to six, but it is more frequent for litters to range between two and four. Gestation period for this species is about 12 to 16 days per litter, which is then followed by two months in the mother’s pouch. While in the pouch, they feed on one of the eight teats on the mother’s abdominal region in its pouch. Not all of the teats get used at one time because of the average litter size and the rapid weaning of the litters. This rapid sexual cycle allows the female to have the capability to be in heat before one litter is weaned, meaning it is able to have another litter almost immediately after the prior one leaves the pouch. After the young leave the pouch, around 70 to 75 days after birth, they are left to live and fend for themselves because the solitary nature of this species. With the reproduction of a new litter being so accelerated, females as well as males can reach reproductive maturity within four to six months of being born. ("Bandicoots", 2006; "Isoodon obesulus - southern brown bandicoot (Eastern)", 2015; "Quenda: Isoodon obesulus (Shaw, 1797)", 2012; Driessen and Rose, 2015)

  • Breeding interval
    Southern brown bandicoots can breed up to four times per season.
  • Breeding season
    July-Feburary
  • Range number of offspring
    2 to 6
  • Average number of offspring
    2.73
    AnAge
  • Range gestation period
    12 to 16 days
  • Average gestation period
    15 days
  • Range weaning age
    60 to 70 days
  • Range time to independence
    70 to 75 days
  • Range age at sexual or reproductive maturity (female)
    4 to 6 months
  • Range age at sexual or reproductive maturity (male)
    4 to 6 months

Parental investment varies greatly between the male and female southern brown bandicoot. The male does not partake in the investment or care of its young outside of the act of mating. Female southern brown bandicoots have a greater investment involving its young. As marsupials, females carry their young in a pouch for an average of 60 days, until the young are weaned off. After weaning, the young are considered independent. ("Isoodon obesulus - southern brown bandicoot (Eastern)", 2015; "Quenda: Isoodon obesulus (Shaw, 1797)", 2012; Birkhead and Moller, 1998; Driessen and Rose, 2015)

Lifespan/Longevity

The southern brown bandicoot lives between two to four years. While there is not a wealth of information dealing with the southern brown bandicoot’s lifespan specifically, there are studies looking at other species in the bandicoot family. Concerning Australian bandicoots as a whole, in captivity there is a forty percent chance that the young will reach sexual maturity while in the wild it drastically drops to eleven and a half percent. ("Bandicoots", 2006; )

  • Range lifespan
    Status: wild
    2 to 4 years
  • Typical lifespan
    Status: wild
    2 to 3 years
  • Average lifespan
    Status: captivity
    6.5 years
    AnAge

Behavior

Southern brown bandicoots are generally nocturnal, but they can also be diurnal, especially during the winter season. This species is active for six to seven hours a day, with almost all of its time is spent searching for food, getting water, or grooming and feeding. When the southern brown bandicoot needs to build shelter for itself, it gathers various shrubbery and vegetation that it comes across. It uses what it has collected and builds a nest-like pile that gets placed over a shallow hole such as a vacant rabbit hole or concavity on the soil surface. This species chooses nest areas that will provide adequate shelter and are well hidden by substantial vegetation. Bandicoots are solitary, except during the breeding season. When males meet one another, hostility can be shown. In determining dominance, the individuals will bite and attack each other with their forepaws. During these attacks it is commonly seen for a male to bite off a part of another males’ tail. Females, on the other hand, when coming in contact with males or other females, have a tendency to avoid one another. (Driessen and Rose, 2015; "Quenda: Isoodon obesulus (Shaw, 1797)", 2012)

Home Range

The home range for the southern brown bandicoot varies on the amount of other bandicoots centralized in one space. Males can have a range varying between two to seven hectares, while females range between one to three hectares. As for territory, it is unclear whether or not this species has a distinguished area that it protects. Instead, avoidance of one another is practiced unless it is time to breed. ("Quenda: Isoodon obesulus (Shaw, 1797)", 2012)

Communication and Perception

The southern brown bandicoot is a nocturnal creature that has well adapted eyesight, but its sense of smell is superior. Between two different males the southern brown bandicoot has been observed to aggressively naso-nasal and naso-anal sniff each other, retreat, and then repeat. Female-female and female-male interactions have been seen to generally avoid each other. There are four specific sounds and vocalizations that this species have been found to make. To locate one another they use a high-pitch noise that is bird-like. When feeling threatened, a vocalization which sounds like loud “chuff, chuff” will be coupled with an equally loud squeaky whistle. Another communication sound made is when the southern brown bandicoot is experiencing fear or if it is in pain, a loud shriek is expelled. The last known vocalization made by this species is a “whuff, whuff” sound that is made when irritated. ("Bandicoots", 2015; Driessen and Rose, 2015; "Isoodon obesulus - southern brown bandicoot (Eastern)", 2015)

Food Habits

Southern brown bandicoots are omnivores, and their diet consists of plants, fungi, and invertebrates. Commonly-consumed invertebrates include ants, beetles, earthworms, centipedes, crickets, butterflies, and earwigs. However, for plants and fungi, species consumed will vary depending on the season.

When searching for food, the southern brown bandicoot mainly digs small holes in the soil and uses its sense of smell to locate food sources. It is extremely common for multiple holes to be dug if it is found that there is a high concentration of food in a central area. However, it has also been observed searching through the aboveground vegetation to forage. A key indication when looking for a spot where foraging has occurred is to look for small scratch marks in the soil. These marks are distinct because of their cylindrical shape. This shape allows this species the ability to stick its long nose into the ground. These holes can be found to be as deep as several centimeters. ("Bandicoots", 2006; Driessen and Rose, 2015; "Isoodon obesulus - southern brown bandicoot (Eastern)", 2015; "Quenda: Isoodon obesulus (Shaw, 1797)", 2012)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods
  • terrestrial worms
  • Plant Foods
  • leaves
  • seeds, grains, and nuts
  • flowers
  • Other Foods
  • fungus

Predation

Predation upon the southern brown bandicoot has been found to be by larger animals. This includes such animals like the european red fox (Vulpes vulpes), wild dogs (Canis lupus familiaris), and both domestic and feral cats (Felis catus). Barn owls (Tyto alba) and tiger snakes (Notechis scutatus) also are known predators.

Although as a means of protection, the southern brown bandicoot heavily utilizes ground vegetation as camouflage. ("Bandicoots", 2006; "Isoodon obesulus - southern brown bandicoot (Eastern)", 2015; "Isoodon obesulus ssp. obesulus", 2008; "Quenda: Isoodon obesulus (Shaw, 1797)", 2012; "Southern brown bandicoot (Isoodon obesulus) Recovery Plan", 2006)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

The southern brown bandicoot burrows into the ground when looking for shelter or food. When it does this digging it turns over an average of 10 kilograms of soil per day. This turnover allows for soil to better allow the germination of seeds, because it is easier for the seeds to get rooted into a top soil with more moisture instead of a harder, dryer top soil crust. There are two protozoan parasites that affect this species: Giardia and Eimeria quenda. (Bennett and Hobbs, 2016; Cahill, 2013; Hillman, et al., 2016)

Commensal/Parasitic Species
  • Protozoa (Giardia)
  • Protozoa (Eimeria quenda)

Economic Importance for Humans: Positive

There are no known positive economic effects of Isoodon obesulus on humans.

Economic Importance for Humans: Negative

There are no known detrimental economic effects on humans by Isoodon obesulus.

Conservation Status

The southern brown bandicoot is considered a species of “Least Concern” according to the IUCN Red List. There is not other status of this species on the US Federal List, the CITES, or the State of Michigan List.

Urbanization and the general clearing of forests and other areas has caused a decrease in the population across areas of Australia and Tasmania. Even though this species is declining, there is an assumed high population and wide distribution of the southern brown bandicoot, especially in areas protected as a national park.

There are recovery plans set in place because of the documented declines. Measures include ensuring that its habitat is protected, the building of a network between government and non-government organizations to facilitate the recovery of this population, and promoting public awareness of this decline. There are several projects in place, such as the St. Helens Biolink Project which aides in monitoring of foxes, a potential predator. (Friend, et al., 2008)

Contributors

Kasey Blevins (author), Radford University, Cari Mcgregor (editor), Radford University, Zeb Pike (editor), Radford University, Karen Powers (editor), Radford University, April Tingle (editor), Radford University, Jacob Vaught (editor), Radford University, Genevieve Barnett (editor), Colorado State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

insectivore

An animal that eats mainly insects or spiders.

intertidal or littoral

the area of shoreline influenced mainly by the tides, between the highest and lowest reaches of the tide. An aquatic habitat.

motile

having the capacity to move from one place to another.

mycophage

an animal that mainly eats fungus

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

omnivore

an animal that mainly eats all kinds of things, including plants and animals

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

soil aeration

digs and breaks up soil so air and water can get in

solitary

lives alone

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

State of New South Wales and Office of Environment and Heritage. Bandicoots. none. State of New South Wales: State of New South Wales and Office of Environment and Heritage. 2015. Accessed April 15, 2016 at http://www.environment.nsw.gov.au/help/copyright-disclaimer.htm.

2006. Bandicoots. Pp. 824-827 in P Macdonald, ed. The Encyclopedia of Mammals: Volume III. Marsupials, Insect Eaters, and Small Herbivores, Vol. 3, 3 Edition. N/A: Facts on File.

Australian Government: Department of the Environment. Isoodon obesulus - southern brown bandicoot (Eastern). N/A. Canberra: Australian Government: Department of the Environment. 2015.

Government of South Australia: Department for Environment and Heritage. Isoodon obesulus ssp. obesulus. FIS 90346. Biodiversity Conservation Unit, Adelaide Region: Department for Environment and Heritage. 2008.

Department of Environment and Conservation. Quenda: Isoodon obesulus (Shaw, 1797). N/A. Government of Western Australia: Department of Environment and Conservation. 2012.

Department of Environment and Conservation (NSW). Southern brown bandicoot (Isoodon obesulus) Recovery Plan. N/A. Hurtsville, NSW: NSW DEC. 2006.

Bennett, M., R. Hobbs. 2016. A new Eimeria species parasitic in Isoodon obesulus (Marsupialia: Peramelidae) in Western Australia. Journal of Parasitology, 102/1: 1129-1131.

Birkhead, T., A. Moller. 1998. Sperm Competition and Sexual Selection. San Diego, California: Academic Press.

Cahill, D. 2013. "Bandicoots identified as ‘ecosystem engineers’" (On-line). Accessed March 25, 2016 at http://www.sciencewa.net.au/topics/environment-a-conservation/item/2244-bandicoots-identified-as-‘ecosystem-engineers’.

Dowle, M. 2012. A Comparison of Two Species of Bandicoots (Perameles nasuta & Isoodon obesulus) Influenced by Urbanisation: Population Characteristics, Genetic Diversity, Public Perceptions, Stress and Parasites (Ph.D. dissertation). Australia: Macquarie University.

Driessen, M., R. Rose. 2015. Isoodon obesulus (Peramelemorphia: Peramelidae). Mammalian Species, 47: 112-123.

Duffy, D., R. Rose. 2007. Milk composition and growth in the southern brown bandicoot, Isoodon obesulus (Marsupialia:Peramelidae). Australian Journal of Zoology, 55: 323–329.

Friend, T., K. Morris, J. van Weenen, J. Winter, P. Menkhorst. 2008. "Isoodon obesulus" (On-line). The IUCN Red List of Threatened Species. Accessed January 27, 2016 at http://www.iucnredlist.org/details/40553/0.

Gemmell, R., G. Johnston. 1985. The development of thermoregulation and the emergence from the pouch of the marsupial bandicoot Isoodon macrourus. Chicago Journals, 58/3: 299-302.

Haby, N., J. Conran, S. Carthew. 2013. Microhabitat and vegetation structure preference: An example using southern brown bandicoots (Isoodon obesulus obesulus). Journal of Mammalogy, 94/4: 801-812.

Hillman, A., A. Ash, A. Elliot, A. Lymbery, C. Perez, A. Thompson. 2016. Confirmation of a unique species of Giardia, parasitic in the quenda (Isoodon obesulus). International Journal for Parasitology: Parasites and Wildlife, 2016: 1-6.

Larcombe, A. 2002. Effects of temperature on metabolism, ventilation, and oxygen extraction in the southern brown bandicoot Isoodon obesulus (Marsupialia: Peramelidae). Physiological and Biochemical Zoology: Ecological and Evolutionary Approaches, 75/4: 405-411.

Nowak, R. 1999. Walker's Mammals of the World, 6th Edition: Volume 1. Baltimore, Maryland: Johns Hopkins University Press.

Paull, D., D. Mills, A. Claridge. 2012. Fragmentation of the southern brown bandicoot Isoodon obesulus: Unraveling past climate change from vegetation clearing. International Journal of Ecology, 2013: 1-11.

Warburton, N., L. Gregoire, S. Jacques, C. Flandrin. 2013. Adaptations for digging in the forelimb muscle anatomy of the southern brown bandicoot (Isoodon obesulus) and bilby (Macrotis lagotis). Australian Journal of Zoology, 61: 402-419.

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