Spotlight on Australia
The Australian continent, which is similar to a very large island, has been isolated from the rest of the world’s land masses for so long that it has developed a tremendous diversity of endemic plants and animals, found nowhere else on Earth. Reports from early European explorers, who traveled to Australia, unsettled the people back home. They told stories of animals as fast and as big as greyhounds that could leap like grasshoppers (kangaroos), gigantic birds that could not fly (emus), and foxes that could (fruit bats)!
Imagine their reaction to the platypus, an animal with the bill of a duck, the body and tail of a beaver, and the webbed feet of an otter.
Australia is best known for its marsupials, from the large grazing kangaroos to the real-life teddy bear, the koala. In contrast to placental mammals, marsupials lack a well-developed womb for nurturing their young for long periods, so the young are born very premature and must continue their development attached to a teat outside the mother’s body.
Most marsupials have a pouch, or at least a flap of skin, to protect their developing young. The only marsupials surviving outside of Australia are the opossums and opossum-rats of South, Central, and North America.
Australia has the world’s highest extinction rate for mammals in modern times. Although Australia is not densely populated by humans, much of its land has been heavily impacted by soil degradation, deforestation, and coastal pollution.
A recent estimate reports that more than 50 percent of the country’s soils are degraded from cattle and sheep ranching and other agriculture, and over 75 percent of the native vegetation has been extensively damaged or destroyed.
In addition, introduced species plants, and diseases have out-competed, preyed-upon and killed Australia’s native flora and fauna. According to a 1990 report by the International Union for the Conservation of Nature (IUCN)approximately 120 mammal species, 100 birds, 150 reptiles, 40 amphibians, 80 fish, 400 invertebrates and over 3,000 plants are threatened or endangered.