Bettongia gaimardi
Tasmanian bettong

Predation and habitat destruction in the early 1900s have restricted Tasmanian bettongs, Bettongia gaimardi cuniculus, to their current range, which includes most of the eastern half of Tasmania. Bettongia gaimardi inhabits arid regions, semi-arid regions, and sclerophyll forests of Tasmania and formerly parts of southern Australia. Eastern bettongs, B. g. gaimardi, were once found on mainland Australia in southern New South Wales and Victoria along the coast but are now extinct. ("Parks and Wildlife Services Tasmania", 2003; "Parks and Wildlife Services Tasmania", 2004; "Tasmanian Bettong", 2003; Rose and Rose, 1997; Rose, 1986; Rose, 1997; Rose, et al., 1998; Wakefield, 1967)

Bettongia gaimardi is found in terrestrial, temperate habitats including grasslands, grassy woodlands, dry eucalyptus forests, and sclerophyll forests (i.e., forests containing plants with hard, short and usually spiky leaves). This species is found from sea level to elevations around 1,000 m. ("Parks and Wildlife Services Tasmania", 2003; "Tasmanian Bettong", 2003; Wakefield, 1967)

Bettongia gaimardi has a small, compact body. Average total length is 65 cm. Males are slightly longer and thinner than females, although sexual dimorphism is not pronounced. These animals weigh between 1.2 and 2.3 kg.

Pelage is light brown with white flecks. This species has the longest fur and the lightest coloration in Bettongia. The long tail gradually gets darker from base to tip. The hair is slightly longer on the tail and has white tips, a distinguishing characteristic of B. gaimardi. The tail of B. gaimardi tends to be slightly longer than its head-body measurement, although both range between 32 and 33 cm in adults. The belly is very light in color. Digits II and III are, as in other macropods, syndactylous.

An adult female has four teats and a forward opening pouch. A resting, non-lactating female has a basal metabolic rate of approximately 229 kJ/day or 0.51 g of oxygen per hour.

Body temperatures vary with time of day and with estrous cycle, but typically fall between 36.2°C (midday) and 37.5°C (midnight). Bettongia gaimardi sweats to cool off, using sweat glands on its hind limbs, at the base of the tail, and inside the female’s pouch. ("Parks and Wildlife Services Tasmania", 2003; "Parks and Wildlife Services Tasmania", 2004; Fisher, et al., 2001; Rose and Rose, 1997; Rose, 1986; Rose, 1997; Rose, et al., 1998; Wakefield, 1967)

Female B. gaimardi will not allow males near them except while in heat or while the males check the female for estrus by sniffing. If the male takes too long to check, the female will sometimes kick and hiss until the male leaves. Estrus lasts one night, though mating may occur several times during that single night so occasionally a male and female may be seen together. The estrous cycle lasts 22 to 23 days. Bettongia gaimardi is believed to be polygynous and to breed continuously, however, harsh environment conditions may limit breeding in the wild. ("Parks and Wildlife Services Tasmania", 2003; "Parks and Wildlife Services Tasmania", 2004; "Tasmanian Bettong", 2003; Fisher, et al., 2001; Rose, 1986; Rose, 1997)

As in other macropods, B. gaimardi embryos experience a pause in development between fertilization and implantation. A single female may have one young leaving and re-entering the pouch, another suckling, and a third offspring in utero waiting to implant. This allows for continuous reproduction with offspring at all stages of development, and allows for fast replacement of young should one be lost. The estrous cycle is 1.5 days shorter in a pregnant female so that she gives birth just before releasing another egg. Before birth, the pouch muscles tighten so that older offspring cannot re-enter it. The female’s reproductive tract also lacks a birth canal, which forms just before birth and degenerates after birth. It is re-formed for every offspring. Males are atypical for macropods because they do not have a forked penis.

Females can produce 1 offspring per gestation but because a female can produce up to 3 young per year, she can have as many as 10 to 15 young in her lifetime. The young are born ectothermic, blind, and poorly developed. They gradually attain the ability to produce metabolic heat, open their eyes, and continue development in the pouch. The gestation period is 21 days with a 105 day pouch life, and there are 106 days between consecutive births. ("Tasmanian Bettong", 2003; Fisher, et al., 2001; Rose, 1986; Rose, 1997; Rose, et al., 1998; Wakefield, 1967)

Male B. gaimardi do not take part in parenting; females are solely responsible for the young. Females carry each offspring first in utero and then in the pouch, protecting it and nursing it until the offspring can become independent. The offspring then leaves its mother's nest and disperses. (Fisher, et al., 2001; Wakefield, 1967)

Little is known about the lifespan of Tasmanian bettongs in capitivity and there is debate about its lifespan in the wild. In captivity, B. gaimardi can live between 7 and 12 years, and its wild lifespan is much shorter, ranging from 3 to 6 years on average. ("Parks and Wildlife Services Tasmania", 2004; Fisher, et al., 2001; Rose, 1986)

Bettongia gaimardi is nocturnal. It builds several nests on its territory and has been known to use 5 or 6 nests at a time. Its semi-prehensile tail allows it to pick up and carry grasses or brush while collecting more nesting material or while foraging. The tail is held off the ground and is used as a counterbalance weight. Bettongia gaimardi often uses its forelimbs to dig for fungi, forage for other food sources, or when moving slowly, but it relies mostly on its larger hind limbs for fast movements like escaping from predators. Both sexes are territorial. It is generally a solitary creature except during the mating season or when a female is with her young before weaning. Males in captivity will establish dominance hierarchies if housed together. ("Tasmanian Bettong", 2003; Wakefield, 1967)

A female’s average territory is 35 to 55 hectares (86 to 136 acres). Males typically have slightly larger territories. ("Tasmanian Bettong", 2003; Fisher, et al., 2001; Rose, et al., 1998; Wakefield, 1967)

Adult female B. gaimardi are known to make “tsk-tsk” sounds to call their young back to the pouch. Other species in Bettongia are reported to use their hind limbs to thump the ground and B. gaimardi is known to use scent glands near the anus to mark territories. Because of the interaction with the mother while living in her pouch, it is likely that tactile communication plays an important role between a mother and her young. Tactile communication is also likely to be important during mating.

Bettongia gaimardi is mycophagous. Fungi may comprise as much as 80% of the diet. Other foods may be eaten, but fungi are preferred and unless it is scare. Bettongia gaimardi forages by hopping slowly using all four limbs and often uses the forelimbs to dig for food. ("Parks and Wildlife Services Tasmania", 2003; "Parks and Wildlife Services Tasmania", 2004; Rose, 1997; Wakefield, 1967)

Foxes contributed to the extinction of bettongs on the Australian mainland. Thylacines, Thylacinus cynocephalus, were a likely predator before they became extinct in Tasmania. Birds of prey, such as wedge-tailed eagles and owls, prey upon Tasmanian bettongs, as do feral cats and dogs. There have been reports of Eastern quolls preying upon B. gaimardi, but they have been met with skepticism. ("Parks and Wildlife Services Tasmania", 2003; "Parks and Wildlife Services Tasmania", 2004; Rose and Rose, 1997)

Bettongia gaimardi builds a grass nest and enthusiastically digs for fungi. It therefore helps to aerate the soil, and has some impact on plant communities. To the extent that these animals serve as prey, they may also impact predator populations. (Rose and Rose, 1997)

There are no known positive effects of B. gaimardi on humans, though they probably attract a few tourists to Tasmania. ("Parks and Wildlife Services Tasmania", 2003; "Parks and Wildlife Services Tasmania", 2004)

There are no known negative effects of B. gaimardi on humans. However, other species belonging to the genus Bettongia, especially the burrowing bettong, are viewed as agricultural pests because they are known to dig up roots. ("Parks and Wildlife Services Tasmania", 2003; Rose and Rose, 1997; Rose, 1986)

Bettongia gaimardi is a protected species in Tasmania and is considered to be vulnerable because only 5% of its habitat lies within the bounds of national parks or other protected land. The rest of its habitat belongs to private owners who can alter the land at will. Competition with rabbits introduced to Tasmania also poses a threat. Because there was once a reward for its hide on the Australian mainland, hunting, combined with loss of habitat and introduced species, probably drove bettongs to extinction on the mainland.

Bettongia gaimardi cuniculus has been listed on the IUCN as a lower risk, nearthreatened species since 1996. Bettongia gaimardi gaimardi is listed as extinct and has not been recorded since 1910. ("CITES", 2005; "Parks and Wildlife Services Tasmania", 2004; "U.S. Fisheries and Wildlife Services Species Profile", 2005; "2004 IUCN Red List of Threatened Species", 1996; Rose, 1986)

The classification of B. gaimardi has changed considerably over the years. Bettongia gaimardi was first described in 1822 by the French scientist Desmarest and originally classified as two species in the genus Kangurus (Kangurus cuniculus and Kangurus gairmadi). Bettongs received the genus name Hypsiprymnus from Ogilby’s early work in 1837 (cited in Wakefield, 1967); however, the genus name was later changed to Bettongia, a word derived from its aboriginal name "small wallaby". Wakefield’s work in 1967 consolidated the two former species (B. cuniculus and B. gaimardi) into a single species and created two recognized subspecies instead: Bettongia gaimardi cuniculus (Tasmanian Bettong) and Bettongia gaimardi gaimardi (the mainland and now extinct form). For more information on the classification and discovery of B. gaimardi, please see Wakefield, 1967 or "Parks and Wildlife Services Tasmania" 2003.

For pictures of skulls, whole mounts, and drawings of Tasmanian bettongs (and other creatures native to the Australia area) please visit Museum Victoria ("Parks and Wildlife Services Tasmania", 2003; Wakefield, 1967)