Australian Animals

by Anthony C.

Australia is perhaps best known for its unique wildlife; 89% of the animal species found in Australia are endemic to the continent, meaning they naturally occur no where else on the planet. This unusually high percentage can in large part be attributed to Australia’s long geographic isolation.

From a zoological perspective, Australia could almost be described as a window into the past, as the types of animals found there are primitive and in many ways indicative of animals which existed everywhere when the continent first became isolated.

The native mammals of Australia are perhaps the most unique, since the very way they reproduce is so fundamentally different to the reproductive habits of other mammals. The vast majority of Australian mammals are either marsupials (metatheria) or monotremes (prototheria), while placental mammals (eutheria) dominate every other landmass.

Marsupials give birth to their young at an extremely early stage of development, and the newborns (which are often no larger than a jelly bean) must then navigate their way around their mother’s body to find a special pouch, this new home contains the nipple from which they can feed and continue their development.

Monotremes are even more primitive, laying eggs like their reptilian ancestors, although the egg is retained for longer and actively provided with nutrients from the mother. Monotremes also lactate, although they have no nipples and instead their mammary glands excrete milk through special openings in the skin.