Australian megafauna

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Marsupial Lion skeleton in Naracoorte Caves, South Australia.

Australian megafauna is a term used to describe a number of comparatively large animal species in Australia, often defined as species with body mass estimates of greater than 30 kilograms, or equal to or greater than 30% greater body mass than their closest living relatives. These species became extinct during the Pleistocene (16,100±100 - 50,000 years before present)^[1] , but exact dates for their extinction have been lacking until recently.

The cause of the extinction is an active and contentious field of research. It is hypothesised that with the arrival of humans (around 48,000-60,000 years ago), hunting and the use of fire to manage their environment may have contributed to the extinction of the megafauna.^[2] Increased aridity during peak glaciation (about 18,000 years ago) may have also contributed to the extinction of the megafauna. Some proponents claim climate change alone caused extinction of the megafauna, but these arguments have to account for the fact that megaufaunal species comfortably survived two million years of climatic oscillations, including a number of arid glacial periods, before their sudden extinction.

New evidence based on accurate optically stimulated luminescence and Uranium-thorium dating of megafaunal remains suggests that humans were the ultimate cause of the extinction of megafauna in Australia.^[3] The dates derived show that all forms of megafauna became extinct in the same rapid timeframe — approximately 47,000 years ago — the period of time in which humans first arrived in Australia. The dates derived suggest the main mechanism for extinction was human burning of a then much less fire-adapted landscape; analysis of oxygen and carbon isotopes from teeth of megafauna indicate sudden, drastic, non-climate-related changes in vegetation and the diet of surviving marsupial species, as well as the loss of megafaunal species. Further analysis of oxygen and carbon isotopes from teeth of megafauna indicate the arid regional climates at the time of extinction were similar to arid regional climates of today, and that the megafauna were well adapted to arid climates.

1 Living Australian megafauna
2 Extinct Australian megafauna: pre-1788
3 Extinct Australian megafauna: post 1788
4 Mythological Australian megafauna
5 References
6 External links

[edit] Living Australian megafauna

[edit] Mammals

Red Kangaroo.

Red Kangaroo (Macropus rufus) This species is a very large kangaroo with short, red-brown fur, fading to pale buff below and on the limbs. It has long, pointed earlobes and a squared-off muzzle. Females are smaller than males and are blue-grey with a brown tinge, pale grey below, although arid zone females are coloured more like males. It has two appendages with small claws (much like arms), two muscular legs, which are used for jumping, and a tail, which is often used like a third leg for balance.

Red Kangaroos' legs work much like a rubber band. The male Red Kangaroo can leap in full force approximately 30 feet (9.14 meters) in one leap. Males grows up to 1.8m (6ft) tall and weigh up to 85 kg (187lbs). Females grow up to 1.1m (3.6ft) tall and weigh up to 35kg (77lbs). Tails can be up to 1m (3ft) along.

Eastern Grey Kangaroo (Macropus giganteus) is a marsupial found in southern and eastern Australia, with a population of several million. Although a big Eastern Grey male typically weighs around 66 kg (145 lb.) and stands almost 2 m (6 ft.) tall, the scientific name, Macropus giganteus (gigantic large-foot), is misleading, as the Red Kangaroo of the semi-arid inland is larger.

Antilopine Kangaroo (Macropus antilopinus), sometimes called the Antilopine Wallaroo or the Antilopine Wallaby, is a species of macropod found in northern Australia: in Cape York Peninsula in Queensland, the Top End of the Northern Territory, and the Kimberley region of Western Australia. It is a locally common, gregarious grazer.^[4]

[edit] Birds

Cassowary

Emu The emu was first described under the name of the New Holland Cassowary in Arthur Phillip's Voyage to Botany Bay, published in 1789.[4] The species was named by ornithologist John Latham, who collaborated on Phillip's book and provided the first descriptions of and names for many Australian bird species; its name is Latin for "fast-footed New Hollander". The etymology of the common name Emu is uncertain, but is thought to have come from an Arabic word for large bird that was later used by Portuguese explorers to describe the related Cassowary in New Guinea.[5] In Victoria, some terms for the emu were Barrimal in the Djadja wurrung language, myoure in Gunai, and courn in Jardwadjali.[6]

In his original 1816 description of the emu, Vieillot used two generic names; first Dromiceius, then Dromaius a few pages later. It has been a point of contention ever since which is correct; the latter is more correctly formed, but the convention in taxonomy is that the first name given stands, unless it is clearly a typographical error.[7] Most modern publications, including those of the Australian government,[8] use Dromaius, with Dromiceius mentioned as an alternative spelling.

Cassowary The Northern and Dwarf Cassowaries are not well known. All cassowaries are usually shy, secretive birds of the deep forest, adept at disappearing long before a human knows they are there. Even the more accessible Southern Cassowary of the far north Queensland rain forests is not well understood.

The Southern Cassowary is the largest bird in Australia and the second largest remaining bird in the world (after the ostrich).^{[citation needed]}

Adult Southern Cassowaries are 1.5 to 1.8 m (5 to 6 feet) tall, although some may reach 2 m (6 feet 8 inches), and weigh about 60 kilograms (130 pounds).^{[citation needed]} Females are bigger and more brightly coloured.^{[citation needed]}

[edit] Reptiles

Goanna

Perentie

Being predatory lizards, goannas are often quite large, or at least bulky, with sharp teeth and claws. The largest is the Perentie (Varanus giganteus), which can grow over 2m in length. They prey on all manner of small animals; insects, lizards, snakes, mammals, birds, eggs. Meals are often eaten whole, and thus the size of their meals depends on the size of the animal itself. However, the Perentie has been observed killing a young kangaroo, and then biting out chunks of flesh like a dog. Goannas have even been blamed for the death of sheep by farmers, though most likely erroneously, as goannas are also eaters of carrion and are attracted to rotting meat.

Not all goannas are gargantuan. Pygmy goannas may be smaller than a man's arm. The smallest of these, the short-tailed monitor (Varanus brevicuda) reaches only 20 cm in length. They survive on smaller prey such as insects and mice.

Carpet Python

There are many further species in the carpet python complex, including the ochre-red Bredl's or Centralian python (Morelia bredli). This python, which is native to a small area around the MacDonnell Ranges and the town of Alice Springs in Australia's Northern Territory, is a unique member of the complex, having many more smaller scales, so that the body more closely resembles a skin. In captivity, striped, spotted and hypomelanistic specimens have been observed. Bredl's python is a medium sized carpet python, averaging around 5 feet, however it is noted for its thicker girth. Adults can breed at a later age than most carpet pythons.

Saltwater Crocodile

A healthy adult male saltwater crocodile is typically 4.8 to 7 metres (15.75 to 21.6 ft) long, and weighs up to 770 kg (1697 lb), with many exceptions being much larger than this. Many large sizes have been reported[1][2], [1] Females are much smaller than males, with typical female body lengths in the range of 2.5–3 meters. A 28 foot (8.5 meters) individual was reportedly shot on the Norman River of Queensland in 1957 and a cast was made of this animal (which can be viewed and is quite the popular tourist attraction), but due to the time since the occurrence and lack of rock hard evidence (other than the plaster) it is not considered "official". The saltwater crocodile has fewer armor plates on its neck than other crocodilians, and its broad body contrasts with most other lean crocodiles, leading to early unverified assumptions the reptile was an alligator.[2]Crocodylus porosus (Schneider, 1801), by Adam Britton from the Crocodilian Species List.