AY Honors/Marsupials/Answer Key

The Numbat (Myrmecobius fasciatus) is a small marsupial endemic to Western Australia. The Numbat is the sole member of the genus Myrmecobius and the family Myrmecobiidae, one of the three families that make up the order Dasyuromorphia, the generalised marsupial carnivores. Another common name for the Numbat was Banded Anteater, though this has now fallen into disuse. Though it will in fact consume ants, its diet otherwise consists almost exclusively of termites.

Physical description

The Numbat is a small, colourful creature between 20 and a little under 30 cm long, with a finely pointed muzzle and a prominent, bushy tail about the same length as its body. Colour varies considerably, from soft grey to reddish-brown, often with an area of brick red on the upper back, and always with a conspicuous black stripe running from the tip of the muzzle through the eyes to the bases of the small, round-tipped ears. The underside is cream or light grey; weight varies between 280 and 550 grams.

Unlike most other marsupials, the Numbat is diurnal, largely because of the constraints of having a specialised diet without having the usual physical equipment for it. Most ecosystems with a generous supply of termites have a fairly large creature with a very long, thin, sticky tongue for penetrating termite colonies, and powerful forelimbs with heavy claws. Like other mammals that eat termites or ants, the numbat has a degenerate jaw with non-functional teeth, and is unable to chew. Nonetheless, numbats do have a similar dental formula to many other marsupials:Template:Dentition

Reproduction

Breeding takes place in high summer, all females coming into oestrus for a short period in January. Gestation takes about 14 days and four to six young are usually born, one for each teat. They remain on the teat until July, at which time the female leaves them in the burrow, returning to suckle them from time to time. By early September, the young begin to emerge from the nest for short periods each day, staying very close to the entrance when the mother departs, and playing together or basking in the spring sunshine for an hour or two before returning. Gradually, they venture further from the burrow: they are weaned by late October, sleeping away from their mother by late October, and in December they set off to establish a territory of their own.

Ecology and behaviour

Adult Numbats are solitary and territorial; an individual of either sex establishes a territory of up to 150 hectares (370 acres) early in life, and defends it from others of the same sex. The animal generally remains within it from that time on; male and female territories overlap, and in the breeding season males will venture outside their normal home range to find mates.

While the numbat has relatively powerful claws for its size, it is not strong enough to get at termites inside the concrete-like mound, and so must wait until the termites are active. It uses a well-developed sense of smell to locate the shallow and unfortified underground galleries that termites construct between the nest and their feeding sites; these are usually only a short distance below the surface of the soil, and vulnerable to the Numbat's digging claws.

The Numbat synchronises its day with termite activity, which is temperature dependent: in winter it feeds from mid-morning to mid-afternoon; in summer it rises earlier, takes shelter during the heat of the day, and feeds again in the late afternoon.

At night, the Numbat retreats to a nest, which can be in a hollow log or tree, or in a burrow, typically a narrow shaft one or two metres long which terminates in a spherical chamber lined with soft plant material: grass, leaves, flowers and shredded bark.

Conservation status

Until European colonisation, the Numbat was found across most of the area from the New South Wales and Victorian borders west to the Indian Ocean, and as far north as the southwest corner of the Northern Territory. It was at home in a wide range of woodland and semi-arid habitats. The deliberate release of the European Red Fox in the 19th century, however, wiped out the entire Numbat population in Victoria, NSW, South Australia and the Northern Territory, and almost in Western Australia as well. By the late 1970s, the entire population was well under 1000 individuals, concentrated in two small areas not far from Perth, Dryandra and Perup.

It appears that the reason these two small populations were able to survive is that both areas have many hollow logs that may serve as refuge from predators. Being diurnal, the Numbat is much more vulnerable to predation than most other marsupials of a similar size: its natural predators include the Little Eagle, Brown Goshawk, Collared Sparrowhawk and Carpet Python. When the Western Australia government instituted an experimental program of fox baiting at Dryandra (one of the two remaining sites), Numbat sightings increased by a factor of 40.

An intensive research and conservation program since 1980 has succeeded in increasing the Numbat population substantially, and reintroductions to fox-free areas have begun. Despite the encouraging degree of success so far, the Numbat remains at considerable risk of extinction and although no longer on the seriously endangered list, it is still classified as vulnerable.

External links

• ARKive - images and movies of the numbat (Myrmecobius fasciatus)
• Numbat Western Australia's Department of Environment and Conservation (DEC) WebPage.
• Project Numbat - formed to create community awareness and increase involvement in the conservation of the numbat.