Bettongia gaimardi (Desmarest, 1822)

Russell A. Mittermeier & Don E. Wilson, 2015, Potoroidae, Handbook of the Mammals of the World – Volume 5 Monotremes and Marsupials, Barcelona: Lynx Edicions, pp. 600-628 : 626

3.

Eastern Bettong

Bettongia gaimardi

French: Bettong de Gaimard / German: Tasmanien-Blrstenrattenkanguru / Spanish: Betong de Tasmania

Other common names: Eastern Rat-kangaroo, Gaimard’s Bettong, Gaimard'’s Rat-kangaroo, Southern Bettong; Tasmanian Bettong / Tasmanian Rat Kangaroo (cuniculus)

Taxonomy. Kangurus gaimardi Desmarest, 1822 ,

“ environs du port Jackson, sur la cote Est de la Nouvelle-Hollande ” (= Port Jackson, New South Wales, Australia).

The nominate subspecies gaimardi (Desmarest, 1822) of south-eastern mainland Australia is extinct. One extant subspecies recognized.

Subspecies and Distribution.

B. g. cuniculus Ogilby, 1838 — E Tasmania, including Maria I and Bruny I.

Descriptive notes. Head-body 31.5-33.2 cm, tail 28.8-34.5 cm; weight 1.2-2.3 kg. Brownish gray, grizzled with white, dorsally; pale gray to white ventrally. Pale limbs and faint hip stripe. Brownish on head and tail. Tail darkens distally, with a short dorsal crest toward tip; a white tail tip is regularly present. Diploid chromosome numberis 22.

Habitat. Open eucalypt forest and woodland with low (less than 1 m) grassy or shrub understory on infertile soils, from sea level to 1000 m elevation.

Food and Feeding. Mycophagous, consuming primarily hypogeal (truffle-like) fungi obtained by digging with the strong forepaws. Fungi comprise 78-97% of the diet throughout the year, fewer being consumed in the drier months (spring—summer). Other dietary items include seeds, fruits, roots, bulbs, plant exudate, and invertebrates. Forages widely in home range, regularly making movements of 500-600 m within 30 minutes.

Breeding. Both sexes reach sexual maturity between nine and twelve months. Females are continuous breeders, producing one young per pregnancy, and raising up to three young per year. Females exhibit embryonic diapause and mate shortly after giving birth. The estrous cycle is 23 days and gestation 21-22 days. Following birth, the young spends c.3-5 months in the pouch and is weaned at about five months.

Activity patterns. Nocturnal; spends daylight hours in a well-constructed ovoid nest of dry grass and shredded bark placed in a depression dug under a fallen log, shrub, or grass tussock. The nest has a single opening through which the animal emerges after dark, immediately moving away from the area. Nests tend to be clustered within a particular area of the home range. An individual may have up to twelve nests and move regularly between them, or sometimes use same nest for up to a week. Individuals may travel up to 1-5 km to a feeding area.

Movements, Home range and Social organization. Solitary. Home range estimates are 47-85 ha for males and 38-63 ha for females. Home range and nesting areas of individuals overlap both within and between sexes.

Status and Conservation. CITES Appendix I. Classified as Near Threatened on The IUCN Red List. The mainland population is listed as extinct in Australia. The Eastern Bettong is now confined to the eastern two-thirds of Tasmania. The nominate subspecies (B. g. gaimardi ), which formerly occurred in coastal mainland Australia from south-east Queensland to south-eastern South Australia, became extinct by the 1920s, most likely as a result of predation by the introduced Red Fox (Vulpes vulpes). In Tasmania (which until recently was fox-free), the subspecies cuniculus remains common but is threatened by habitat-clearing, as well as habitat degradation due to forestry operations, grazing by domestic livestock, and altered fire regimes. Little of its habitat is in conservation reserves. If the recently introduced Red Fox succeeds in becoming established in Tasmania, the bettong is likely to decline precipitously, possibly to extinction, as it did on the mainland. In 2011-2012, Eastern Bettongs from Tasmania were reintroduced to the Australian mainland in a 450ha fenced enclosure at Mulligan Flats Nature Reserve, north of Canberra, Australian Capital Territory, and a captive population was also established.

Bibliography. Abbott & Burbidge (1995), Claridge et al. (2007), Hayman (1989), Johnson (2003), Menkhorst (2008d), Menkhorst & Knight (2001), Rose (1986, 1987), Rose & Johnson (2008), Sarre et al. (2013), Seebeck et al. (1989), Taylor (1993a, 1993b), Woinarski et al. (2014bf, 2014bg).

Figures

1. Rufous Bettong (Aepyprymnus rufescens), 2. Burrowing Bettong (Bettongia lesueur), 3. Eastern Bettong (Bettongia gaimardi), 4. Brush-tailed Bettong (Bettongia penicillata), 5. Northern Bettong (Bettongia tropica), 6. Long-footed Potoroo (Potorous longipes), 7. Long-nosed Potoroo (Potorous tridactylus), 8. Gilbert's Potoroo (Potorous gilbertii)

Subspecies and Distribution. B. g. cuniculus Ogilby, 1838 — E Tasmania, including Maria I and Bruny I.