Northern Brown Bandicoot
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| Isoodon macrourus (Gould, 1842) |
The Northern Brown Bandicoot (Isoodon macrourus), a marsupial species, is a bandicoot found only on the northern and eastern coasts of Australia and nearby islands, mainly Papua New Guinea. It is not, however, found far inland in Australia where the environment is extremely hot and unsuitable for most organisms.
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[edit] Habitat
The populations of I. macrourus live in two different habitats: one during the dry season and the other during the wet season. During the dry season, this species lives in thick vegetation consisting of tall weeds, small trees, and dense shrubs. This probably occurs because of the sparse food supply that can be found. During the wet season though, I. macrourus "come out" and roam open grasslands where a more abundant food source exists.
The Northern Brown Bandicoot makes individual nests or homes on the ground consisting of simple mounds of hay and twigs that are well camouflaged and waterproof. The inside is hollow and large enough for just the single bandicoot. Some bandicoots use hollowed out tree trunks or abandoned rabbit dens for shelter. In general however, I. macrourus shows a strong preference for homes in areas of low ground cover.
[edit] Physical description
These bandicoots can be set apart from other marsupials by two traits. They are both polyprotodont and syndactylous. I. macrourus has typical body and tail lengths of 40 cm and 15 cm, respectively. On average it weighs 1200 g. This rodent-like marsupial has a thick harsh coat but is not spiny. The dorsal pelage is light brown in appearance with speckled black patterns throughout. On the ventral surface it is solid white. This bandicoot also has short, rounded ears and a short nose. One can easily mistake Northern Brown Bandicoot for Isoodon obesulus, the Southern Brown Bandicoot. The two species differ in both size, with I. macrourus larger, and regional locality, in that I. obesulus are found only on the southern coastline of Australia.
The male is typically 5–7 cm longer and half a kilogram heavier than the female.
[edit] Reproduction
The Northern Brown Bandicoot breeds throughout the year. An average litter consists of 2 to 4 young. Being marsupials, the newborns are naked and immature and thus undergo extensive development within the mother's pouch. The gestation period (12.5 days) is the shortest recorded for any mammal. Bandicoots are also the only metatherian marsupials that have placentas similar to eutherian mammals. Juveniles are weaned at 60 days post partum. By this time, the marsupial young are capable of sustaining endothermy on their own. I. macrourus have a lifespan of approximately two years.
Female bandicoots produce between 8 and 11 litters in their lifetime. Male bandicoots don't play a significant role in the care of juvenile I. macrourus.
[edit] Behavior
The Northern Brown Bandicoot diligently marks and retains its territory. It has scent glands on the ears, mouth, pouch, and cloaca. This solitary marsupial is aggressive only towards others of its species. If a bandicoot is startled in its nesting site, it will flee. Hardly ever will I. macrourus defend itself unless two males confront one another over territorial rights. Then, either a male is killed or one male becomes subordinate to the other and avoids confrontation. The subordinate male also forfeits to the dominant male all sexual relations with local females. Bandicoots are not social animals and do not live in groups, with the exception of mother and her young.
[edit] Food habits
I. macrourus is omnivorous. It eats insects, earthworms, berries, and grass seeds. Sometimes when food is scarce, the female bandicoot will eat her young. This marsupial forages alone during the night and has a keen sense of smell. This allows it to find food either laying in the open or buried underground. Hunting at night, however, also has its consequences. The bandicoot is prime prey for many nocturnal cats, foxes, and owls found in Australia.
[edit] Conservation status
Over the past century, populations of I. macrourus have decreased after the European introduction of rabbits and livestock into Australia. This dramatically heightened the direct competition for food and habitat. Bandicoot populations further suffered after the introduction of the fox and cat, both predators of small animals.
[edit] References
- Australasian Marsupial & Monotreme Specialist Group (1996). Isoodon macrourus. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 12 May 2006.
- ↑ Friend, G., J. Taylor. 1985. Habitat preferences of small mammals in tropical open-forest of the Northern Territory. Australian Journal of Ecology, 10: 173-185.
- ↑ Groves, Colin (16 November 2005). in Wilson, D. E., and Reeder, D. M. (eds): Mammal Species of the World, 3rd edition, Johns Hopkins University Press, 39. ISBN 0-801-88221-4.
- ↑ Gemmell, R., J. Hendrikz. 1993. Growth rates of the bandicoot Isoodon macrourus and the brushtail possum Trichosurus vulpecula. Australian Journal of Zoology, 41: 141-149.
- ↑ Gemmell, R., G. Johnston. 1985. The development of thermoregulation and the emergence from the pouch of the marsupial bandicoot Isoodon Macrourus. Physiological Zoology, 58(3): 299-302.
- ↑ Grzimek, B. 1990. Encyclopedia of Mammals Volume 1. New York, NY: McGraw Hill.
- ↑ Seebeck, J., P. Brown, R. Wallis, C. Kemper. 1990. Bandicoots and Bilbies. Chipping Norton, New South Wales, Australia: Surrey Beatty & Sons Pty Limited.
- ↑ Stonehouse, B., D. Gilmore. 1977. 'The Biology of Marsupials. Baltimore, Maryland: University Park Press.
