Tasmanian bettong (Bettongia gaimardi)

Description

What’s the World’s Favourite Species?

Tasmanian bettong fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Tasmanian bettong description

The Tasmanian bettong (Bettongia gaimardi) is a small, compact marsupial which resembles a slender, delicate kangaroo in appearance. Its hind limbs are well developed and its hind feet are long, allowing the Tasmanian bettong to hop when moving fast ^{(2) (3)}. In contrast, its forelimbs are relatively short, but are well muscled and bear short, spade-like claws which are used for digging ^{(2) (3)}.

The belly of this small mammal is whitish or pale grey ^{(3) (5)}, while its upperparts are brownish-grey with white flecks ⁽⁵⁾. The tail of the Tasmanian bettong is slightly prehensile and is as long as its body, ending in a noticeable white tip. This species has short, rounded ears, a naked nose and only very short fur on its lower limbs, feet and tail ^{(2) (3)}.

Although the male and female Tasmanian bettong are similar in appearance, males are usually slightly longer and slimmer than females. While in the female’s pouch, the young Tasmanian bettong has darker fur than the adult, but this difference disappears by the time the young leaves the pouch ⁽³⁾.

Also known as

eastern bettong, southern bettong, Tasmanian rat kangaroo.

French

Kangourou-rat De Gaimard, Kangourou-rat De Tasmanie.

Spanish

Canguro-rata De Tasmania.

Size

Head-body length: 31.5 - 33.2 cm ⁽²⁾

Tail length: 28.8 - 34.5 cm ⁽²⁾

Weight

1.2 - 2.3 kg ^{(2) (3)}

Tasmanian bettong biology

The Tasmanian bettong is a nocturnal omnivore that specialises in feeding on underground fungi ⁽³⁾, which it detects using its keen sense of smell and excavates using its strong front claws ^{(2) (3)}. Around 50 to 90 percent of the Tasmanian bettong’s diet is made up of fungi ⁽⁵⁾, but it will also take some plant material, such as leaves, seeds, fruits and roots, as well as invertebrates ⁽³⁾. Like related species, the Tasmanian bettong is likely to get most of its water requirements from its food ^{(2) (3)}.

Although a predominantly solitary creature, the Tasmanian bettong will occasionally forage in a small, loose group when food is abundant ⁽²⁾. This species hops like a kangaroo when moving fast, but moves along on all fours when travelling slowly, such as when foraging ^{(2) (3)}.

The Tasmanian bettong uses dried grass and shredded bark to build a solitary, domed nest in a sheltered site ^{(3) (5)}, such as a shallow depression in the ground or under a fallen log or clump of vegetation ⁽³⁾. The nest is not permanent, however, lasting only one or two nights before the bettong moves on in search of food ⁽²⁾. Intriguingly, the Tasmanian bettong uses its prehensile tail to carry nest material, tossing the material on top before curling the tail around it and carrying the load to its nest site ⁽³⁾.

After reaching sexual maturity at 7 to 11 months ^{(3) (5)}, the female Tasmanian bettong produces a single young at a time, after a short gestation period of 20 to 22 days ^{(3) (7)}. After birth, the young bettong, known as a joey, is carried in the female’s pouch for around 15 weeks ^{(3) (5) (7)}, although during the last 2 weeks it will spend increasing amounts of time outside of the pouch ⁽³⁾. After leaving the pouch for the last time, the young Tasmanian bettong continues to suckle for around six to nine weeks before it is weaned ⁽⁷⁾.

The female Tasmanian bettong is able to mate again immediately after giving birth. However, while the pouch is occupied, the new embryo enters a period of suspended animation known as embryonic diapause ⁽²⁾. Its development only continues at a later stage, allowing its birth to coincide with the previous young vacating the pouch for the final time ^{(2) (3) (7)}.

The Tasmanian bettong can breed year-round, and the fast turnover of young means that a female can produce around three joeys each year ^{(3) (5) (7)}. The maximum lifespan of this species is around six years, and the female may produce up to eight young in this time ⁽³⁾.

Tasmanian bettong range

Although once also found in the south-eastern region of the Australian mainland, the Tasmanian bettong is now confined to Tasmania ^{(1) (2) (3) (5)}.

Two subspecies of Tasmanian bettong are recognised. Bettongia gaimardi gaimardi formerly occurred on the Australian mainland, from southern Queensland to South Australia, but is now considered to be extinct ^{(1) (2) (3)}. The surviving subspecies, Bettongia gaimardi cuniculus, occurs in the drier eastern and central parts of Tasmania ^{(1) (2) (3)}, and is also present on the nearby Bruny Island and Maria Island, where it was introduced ⁽²⁾.

Tasmanian bettong habitat

The Tasmanian bettong is usually found in habitats prone to wildfires and other disturbances ⁽⁵⁾. It typically inhabits open, dry sclerophyll forest with a grassy or heathy understorey and well-drained, infertile soil ^{(1) (2) (3) (6)}, at elevations up to 1,000 metres ^{(1) (2)}.

Tasmanian bettong status

The Tasmanian bettong is classified as Near Threatened (NT) on the IUCN Red List ⁽¹⁾ and is listed on Appendix I of CITES ⁽⁴⁾.

Tasmanian bettong threats

The main cause of the demise of the Tasmanian bettong on the Australian mainland is believed to be predation by the introduced red fox (Vulpes vulpes) ^{(1) (3) (8) (9)}. It also faced competition and habitat loss caused by introduced rabbits (Oryctolagus cuniculus) and other non-native herbivores, as well as land clearance and changes in fire regimes ^{(2) (8) (10)}.

Although Tasmania has been a safe haven for the Tasmanian bettong for some time, the recent illegal introduction of the red fox could pose a significant threat to the Tasmanian bettong population there ^{(1) (9)}. Feral cats may also predate this small marsupial, and may transmit diseases that the Tasmanian bettong has no defence against ⁽⁸⁾.

Although the Tasmanian bettong is still common in Tasmania, almost all of its habitat occurs on private land that is vulnerable to forestry operations, agricultural development, excessive livestock grazing and the use of poisons to control wallabies ^{(1) (3) (6)}.

Tasmanian bettong conservation

The Tasmanian bettong is listed on Appendix I of the Convention on International Trade in Endangered Species (CITES), meaning that international trade in this species is prohibited ⁽⁴⁾. It is also legally protected throughout its range ⁽⁶⁾, although only five percent of its habitat in Tasmania is currently protected within National Parks ^{(3) (6)}.

In 2002 the Fox Free Tasmania Taskforce was set up, and is now running a Fox Eradication Program to address the threat that foxes pose to native wildlife ⁽⁹⁾. Further recommended conservation measures for the Tasmanian bettong include maintaining suitable habitat, monitoring the bettong’s populations, and implementing measures to reduce the use of poison baits and to educate landowners on their use ⁽¹⁾.

Although not a strong cultural symbol of Australia like its kangaroo and wallaby relatives, the Tasmanian bettong nevertheless plays an important role in its environment. Its scratching and digging have positive effects on the soil and increase the amount of water that can penetrate the ground, while its foraging activity spreads fungal spores that enable plants such as Eucalyptus trees to extract nutrients from the soil ^{(5) (10)}. As part of efforts to restore native woodlands, a project has begun to reintroduce captive-bred Tasmanian bettongs in the Australian Capital Territory, on the Australian mainland. As well as helping research into woodland restoration, this new population will also provide a back-up for the Tasmanian bettong population in Tasmania, and will return a species that has been missing from the area for over 80 years ⁽¹⁰⁾.

Find out more

Find out more about the Tasmanian bettong and about marsupial conservation:

• Australian Government - Department of Sustainability, Environment, Water, Population and Communities (2012) Bettongia gaimardi gaimardi. In: Species Profile and Threats Database. Department of Sustainability, Environment, Water, Population and Communities, Canberra. Available at:
  http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=66656
• Rose, R.W. and Rose, R.K. (1998) Bettongia gaimardi. Mammalian Species, 584: 1-6. Available at:
  http://www.science.smith.edu/msi/pdf/i0076-3519-584-01-0001.pdf
• Maxwell, S., Burbidge, A.A. and Morris, K.D. (1996) The 1996 Action Plan for Australian Marsupials and Monotremes. Wildlife Australia, Canberra. Available at:
  http://www.environment.gov.au/biodiversity/threatened/publications/action/marsupials/index.html

More information on conservation in Tasmania:

• Tasmania Parks & Wildlife Service:
  http://www.parks.tas.gov.au/

Authentication

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

This species information was authored as part of the ARKive and Universities Scheme.

Glossary

Embryonic diapause

Also known as delayed implantation. A reproductive strategy found in some mammals, such as some marsupial, rodent, bear and mustelid species, in which the embryo does not immediately implant in the uterus, but remains dormant, only implanting and continuing development when conditions are favourable. This strategy allows the female to give birth when survival of the offspring is more likely, such as when environmental conditions are more favourable or the previous offspring has been weaned.

Feral

Previously domesticated animals that have returned to a wild state.

Gestation

The state of being pregnant; the period from conception to birth.

Invertebrates

Animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.

Marsupial

A diverse group of mammals characterised by their reproduction, in which gestation is very short, and the female typically has a pouch (marsupium) in which the young are raised. When born, the tiny young crawls to the mother’s teats, where it attaches and stays for a variable amount of time, whilst it continues to develop. Marsupials also differ from placental mammals in their dentition.

Nocturnal

Active at night.

Omnivore

An organism that feeds on both plants and animals.

Prehensile

Capable of grasping.

Sclerophyll

A type of vegetation with hard, thick-skinned leaves; for example, eucalypts and acacias.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

References

1. IUCN Red List (January, 2012)
   http://www.iucnredlist.org/
2. Claridge, A., Seebeck, J. and Rose, R. (2007) Bettongs, Potoroos and the Musky Rat-Kangaroo. CSIRO Publishing, Collingwood.
3. Rose, R.W. and Rose, R.K. (1998) Bettongia gaimardi. Mammalian Species, 584: 1-6. Available at:
   http://www.science.smith.edu/msi/pdf/i0076-3519-584-01-0001.pdf
4. CITES (January, 2012)
   http://www.cites.org/
5. Dickman, C.R. (2007) A Fragile Balance: The Extraordinary Story of Australian Marsupials. University of Chicago Press, Chicago.
6. Rose. R.W. (1986) The habitat, distribution and conservation status of the Tasmanian bettong, Bettongia gaimardi (Desmarest). Australian Wildlife Research, 13: 1-6.
7. Rose, R.W. (1987) Reproductive biology of the Tasmanian bettong (Bettongia gaimardi: Macropodidae). Journal of Zoology, 212: 59-67.
8. Armati, P.J., Dickman, C.R. and Hume, I. (2006) Marsupials. Cambridge University Press, Cambridge.
9. Tasmania Parks & Wildlife Service - Foxes in Tasmania (February, 2012)
   http://www.parks.tas.gov.au/index.aspx?base=3026
10. ACT Government - The Eastern Bettong Project (February, 2012)
    http://www.environment.act.gov.au/cpr/conservation_and_ecological_communities/eastern_bettong_project