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| wombats | marsupial type style and lifestyle |
wombat, (family Vombatidae), . Like marmots, wombats are well-built, almost tailless burrows with small eyes and short ears. However, wombats are larger, measuring 80-120 cm (31-47 in) in length. They feed mainly on nocturnal grasses, and in the case of the common wombat (Vombatus ursinus), they feed on the inner bark of tree and shrub roots. Farmers consider wombats to be pests because they burrow into cultivated fields and pastures and because their burrows may harbour rabbits.
The common wombat has coarse black hair and a bald, grainy nose pad. It is common in the hill forests along the Divide Range in southeastern Australia, from southeastern Queensland to New South Wales and Victoria in southern Australia and Tasmania. Historically, dwarf forms lived on small islands in Bass Strait, but have disappeared due to habitat destruction by cattle grazing.
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Hairy-nosed wombats (genus Lasiorhinus) are more social. They make a grassy nest at the end of a large 30 m (100 ft) underground burrow that is shared with many other wombats. They have silky fur and pointed ears, and the nose is completely hairy, without a bald pillow. The southern hairy-nosed wombat (L. latifrons) is smaller than the common wombat. It lives in the semi-arid country of South Australia, stretching across the Nullarbor Plain in southeastern Western Australia. . barnardi) is larger and differs in skull detail; it is protected by law and most of its inhabitants live in Epping Forest National Park in central Queensland, where only 60-80 remain. Two other groups of hairy-nosed wombats became extinct in the late 19th or early 20th century, one near St George in southwest Queensland and the other at Deniliquin on the Murray River in New South Wales. These are very similar to the Queensland species.
The wombat skull is flat and its bones are very thick. Unlike other marsupials, wombats have constantly growing rootless teeth, adapting to a hardy diet. The two incisors in each jaw are rodent-like; there are no fangs. Wombats almost invariably bear one youngster at a time, which develops for five months or more in the posterior opening pouch. They become sexually mature at two years in a normal wombat and at three years in a hairy-nosed wombat.
The contemporary wombat is related to the extinct giant wombat (Diprotodon) of Australia, which is recognised as the largest marsupial in history. Some palaeontologists separate giant wombats into two species (D. australis and D. small) based on differences in skull size. However, other palaeontologists argue that these differences can be explained by sexual dimorphism (differences in appearance between males and females of the same species) and thus place all giant wombats in the species D. opatum. The largest giant wombat measures the shoulder and averages 3 metres (10 feet) in length. At 2000-2500 kg (about 4400-5500 lb), males weighed more than twice as much as females. Although many scientists claim that humans killed the last giant wombats between 46,000 and 15,000 years ago, some researchers attribute their extinction to the increased aridity in Australia that accompanied the last ice age.
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