Australia has some of the most unique and unusual native animals in the world. Over 90% of the mammals, 7% of the birds, 88% of the reptiles and 94% of the frogs are found only in Australia.
The reason Australia has such unique and unusual animals (and plants) is that it was isolated from the rest of the world for over 60 million years. Separated by vast oceans, Australian plants and animals evolved independently of those in other parts of the world. This is why Australian native animals are so different from those found elsewhere in the world. About 90 percent of the mammals, 70 percent of the birds, 88 percent of the reptiles and 94 percent of the frogs, in Australia, are found nowhere else on earth.
Interestingly many Australian fauna fill similar niches in the local environment to animals elsewhere in the world. For example, the echidna is an Australian anteater. The Tasmanian tiger (now extinct) was a marsupial wolf. The marsupial mole too behaves like moles found in other parts of the world. The existence of similar animals in different parts of the world is referred to as "Parallel Evolution".
Ever wondered what animals are really native to Australia?
Generally speaking, it is any animal that has been in Australia before the arrival of humans. The reason this definition is the most appropriate is because animals such as the koala and emu have been in Australia for millions of years and are unquestionably native. The dingo, on the other hand, which considered native by some, was only brought to Australia by humans about 5,000 years ago. Many other animals such as camels and rabbits were introduced by European settlers less than 200 years ago. These animals are definitely not native to Australia.
Monotremes are mammals that lay eggs like birds and reptiles, but feed their babies milk like other mammals. Monotremes are the only mammals in the world that lay eggs rather than give birth to 'live' babies.
Monotremes first appeared between 145–99 million years ago and are the oldest type of Australian mammals. Two out of the five known species of monotremes in the world live in Australia. The echidna and platypus are two such animals found in Australia.
The word monotreme means "one hole". This is because these mammals have only one opening, called a cloaca, for their anus, urinary and reproductive tracts. This is similar to birds and reptiles.
Marsupials are a group of mammals that carry their babies in a pouch outside their bodies. They have an external pouch located on their mother's abdomen for this purpose. They give birth to very immature and underdeveloped babies and then raise them to full maturity in this outside pouch. This is very different from placental mammals, such as cats, dogs, etc., that grow their babies inside their bodies.
Marsupials first appeared in Australia about 64-65 million years ago and are the second oldest type of mammal found in Australia.
Marsupials in Australia occupies all ecological niches from arboreal, terrestrial and subterranean (in the trees, on the ground and underground). Interestingly, there are no marsupial marine animals. They range in size from the 1.8 meter tall red kangaroo weighing 90kgs to the tiny, shrew-like long-tailed planigale which is just 6 cm in length and weighs only 4 gms.
The word Marsupial (mar-sue-pee-al) comes from the Latin word “marsupium” which means pouch or purse.
The key characteristic of placental mammals is that they give birth to babies that are far more advanced in their development than monotremes and marsupials. They do this by developing the baby inside their body.
Placental mammals are relatively recent arrivals to Australia. Bats were the first to arrive, flying to Australia about 23 million years ago. Rodents arrived about 5-10 million years ago. These animals reached Australia by hitching a ride on floating debris and crossing the oceans that separated Australian from Asia as Australia as it started drifting slowly closer to Asia. These placental mammals make up a very small percentage of the total mammalian population. Humans introduced a number of animals. The dingo was the first of these, coming here about 5,000 years ago. Beginning in 1788 many types of placental mammals such as cattle, the fox and rabbit were brought to Australia.
Australia has many amphibians and reptiles found nowhere else in the world.
Lizards – There are over 700 species unique to Australia alone.
Snakes – Australia has 140 species of land snakes and 32 species of sea snakes. Of these about a 100 are venomous snakes. The bite from about 12 of these can be fatal to humans. The taipan and red-bellied black snake are some such venomous snakes.
Frogs – Four families of native frogs numbering 230 species inhabit the continent. 135 of these are unique to Australia.
Crocodiles – Australia has two species of crocodile. The Saltwater crocodile is the world's largest and can weigh as much as 1,000 kilos and is known to attack humans. Fresh water crocodiles are much smaller and do not attack humans.
Turtles – There are 35 species of freshwater turtles. Six species of sea turtle also visit the coastlines.
Australia has 800 species of birds of these 350 are only found in Australasia.
Ratites such as the emu and cassowary, are large flightless birds similar to the ostrich. The Emu lives in the Australian Outback. And the critically endangered cassowary lives in the tropical rainforests of Australia.
Megapods such as the Mallee fowl, trace their ancestry as far back as Gondwanan time. These stocky birds look somewhat like chickens but they have small heads and large feet (that's why the name "megapod" meaning big-feet). These birds are usually found in forested areas.
Other birds such as Kookaburras are the world's largest kingfishers.
There were no apes or monkeys and also no hoofed animals (like horses, cattle, goats, deer etc.) in Australia either until Europeans came to Australia in 1788. Rats and mice were the only animals that the Europeans didn't bring intentionally. They arrived as stowaways on ships. They rest were imported intentionally.
An introduced animal is any animal that didn't naturally exist in Australia and was "introduced" — that is, brought intentionally or unintentionally by humans.
The first animals to be introduced into Australia by humans was the dingo a wild Australian dog. It was brought here by Asian sea-farers over 5,000 years ago.
Other introduced animals were brought here for agricultural purposes (cattle and sheep), for transportation (camel and horse), for sport (rabbit and fox), for pleasure (myna bird and house sparrow) and for pest control (cane toad). Some of these creatures, such as the cane toad, have been disastrous to the Australian ecology.
According to the Australian Department of the Environment's Endangered Australian Animals List many Australian native animals are endangered and threatened with extinction. For example; even the cuddly koala is listed as vulnerable, the cassowary and night parrot are listed as endangered and the gouldian finch as critical.
Many species of Australian mega-fauna became extinct after the arrival of the Aborigines, first humans to arrive in Australia.
Since the arrival of European settlers in 1788 Australia has lost numerous other native animals and plants. The Tasmanian tiger is a prominent example of a recently extinct Australian animal. The last died in captivity in 1936.
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