Australian Animals Australia's Native and Introduced Wild Animals

 

Australia has some of the most unusual wild animals in the world.
This is a result of their separate evolution on a continent that was isolated for millions of years from other parts of the world.
About 95 percent of the mammals, 70 percent of the birds, 88 percent of the reptiles and 94 percent of the frogs are found nowhere else on earth.
Australia also now has many introduced species of animals, some of which have been fatal to the local native animals.


Why Does Australia Have Unique & Unusual Native Animals?

How the continents were formed

Map of how continents were formed

Up until about 250 millions of years ago the world had just one huge super-continent called Pangaea. Animals and plants intermix with one another on this huge single landmass.

About 200 million years ago this super-continent broke up into two continents — Laurasia and Gondwana. When this separation took place monotremes an marsupials were the predominate mammals of the Gondwana region and placental mammals in Laurasia.

Then about 60 million years ago Gondwana broke up into what became South America, Africa, Antarctica, India and Australia.

Australia and Antarctica slowly drifted southwards,far away from all the other continents, and became completed isolated from the rest of the world by vast oceans. The other continents however stayed relatively close to each other and over time collided or joined parts of the old Laurasia landmass. When these landmasses came together monotremes and marsupials were unable to compete with the more advanced placental mammals and became mostly extinct. In Africa and India marsupials became completely extinct. When South America joined North America almost all the marsupials there also vanished, to be replaced by placental mammals.

Australia, meanwhile, drifted in a vast ocean, isolated from the rest of the world. The animals and plants which were originally on the Australian landmass no longer had contact with creatures from other parts of the world and continued to evolve independently. The Australian environment also became drier and more arid. Monotremes and marsupials were more suitable for this new environment and became the dominate creatures of the Australian continent.

This is why Australian wild animals are so different from those found elsewhere in the world.


Native Australian Animals

Australia's long isolation from the rest of the world has allowed Australian native animals to evolve separately from those in other parts of the world, but to fill similar niches in the environment. For example the Echidna is an Australian Anteater. The Tasmanian Tiger (now extinct) was a marsupial wolf. Marsupial possums and rodents are very similar to their placental counterparts in other parts of the world and occupy similar environmental niches. This is referred to as "Parallel Evolution".

Australian Mammals There are three types of mammals in Australia

Monotremes first appeared between 145–99 million years ago and are the oldest type of mammals to populate Australia. Two out of the five known species of monotremes in the world live in Australia. These are the Echidna and Platypus.

Marsupials appeared about 64-65 million years ago and are the second oldest type of mammal found in Australia. They occupy every niche of the Australian habitat and range from the large Red Kangaroo to marsupials of the smaller than a mouse.

Placental Mammals in Australia today are relatively recent arrivals, bats were the first to arrive getting here about 23 million years ago. Rodents arrived about 5-10 million years ago. These animals reached Australia by flying and crossing the seas that separated Australian from Asia when Australia slowly stated drifting closer to Asia making crossings to the continent possible. 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 5000 years ago.

Australian Birds Australia has 800 species of birds, 350 are found only in Australasia

Ratites such as the Emu and Cassowary, which are large flightless birds similar to the ostrich.

Megapods such as the Mallee fowl, trace their ancestry as far back as Gondwanan time. These birds are stocky birds which look somewhat like chickens. They have small heads and large feet (that's why the name "megapod" meaning big-feet).

Parrots found unique to Australia comprise nearly 20% of the world's know species. These include the cockatoo.

Other birds such as the Kookaburra is the world's largest kingfisher.

Australian Amphibians and Reptiles 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 more poisonous snakes than non-poisonous ones. The Red-bellied Black Snake is one of these.

Frogs Four families of native frogs inhabit the continent.

Crocodiles Australia has two species of crocodile. The Saltwater Crocodile is the world's largest and can grow to 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.

DID YOU KNOW
Australia does not have any land tortoises.

Why are there Marsupials & Monotremes in Australia?

Marsupials and Monotremes are Better Suited for the Australian Environment

Originally, while all the continents were joined together, there were primitive mammals of all sorts in Australia.

When Australia broke off from Gondwana and started drifting off to the south, the environment started to get drier and sparser. Monotremes and marsupial mammals were well suited for the new harsher environment than the placental mammals. Then, about 34 million years ago, there was a huge world-wide extinction event, possibly caused by large scale bombardment of the earth by objects from outer space such as meteors. This seems to have affected the placental mammals more than it did other creatures. From then onwards monotremes and marsupial mammals seem to have thrived in Australia and placental mammals slowly became extinct.

It is believed that these animals were better suited for Australia's harsh arid environment because of their lower metabolic rate and less demanding reproductive system.

Marsupials and monotremes became the dominant mammals of Australia.


What is a Marsupial?

Marsupial (mar-sue-pee-al)

Marsupials mammals got their name from the Latin word “marsupium” which means pouch. All marsupials have an external pouch located on their mother’s abdomen (tummy) in which they carry their young.

Marsupials differ for other mammals in that they give birth to very small underdeveloped babies who must make a dangerous journey from the mother’s birth canal at the bottom to the pouch located on her abdomen. They do this by crawling up the mother's tummy to the pouch. This is the most dangerous time of a young marsupial's life as these babies could easily fall off and die.

Kangaroo with joey in pouch

Once safely in the mother’s pouch the baby, called a Joey, attaches itself to a milk teat where it feeds and grows into a baby animal. A baby kangaroo may live in its mothers pouch for as long as 6 months.

Marsupials of Australia, may have originated in modern day China (East Laurasia). They probably arrived in Australia around 50 million years ago via North America, South America and through the Antarctica.

Once Australia separated from the other continents and started to drift southward the marsupials stranded on it didn't have any competition from more placental mammals. Without competition the marsupials diverged into over 140 different species found in Australia today. Some descendants of those original marsupials even almost hopped their way back towards China reaching as far as Indonesia and Papua New Guinea. Unfortunately the original marsupials in other parts of the world couldn't compete with placental mammals and became mostly extinct.

 

DID YOU KNOW
A few marsupials still survive in other parts of the world. In America these are known as Opossums.

What is a Monotreme?

Monotreme (mo-no-try-m)

A monotreme is a primitive mammal that lays eggs like a bird or reptile but feeds its babies milk like a mammal. Monotremes are warm blooded but have a slightly lower metabolic and heart rate than other mammals. This means they need less energy than equivalent sized mammals. Monotremes have fur but no teeth.

There are only two types of monotremes in the world, both are found in Australia. These are the Echidna and the Platypus. Monotremes lays tiny leathery eggs. The babies lick milk from the fur on their mother's abdomen.

DID YOU KNOW
Monotreme means "one hole". This is because these animals have only opening for their anus, urinary and reproductive tracts. This is similar to birds and reptiles.

Introduced Animals of Australia

Humans deliberately brought various animals into Australia

The first animals to be introduced into Australia was the Dingo or wild Australian dog. It was brought here by sea-farers over 5000 years ago. Other 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 have been disastrous to the Australian ecology.

 

Here are a few which have been ecological disasters:

 

DID YOU KNOW

Until Europeans came there were no hoofed animals (like horses, cattle, goats, deer etc.) in Australia.

Only rats and mice were not brought here intentionally, arriving in Australia as stowaways on ships.

 


Endangered & Threatened Animals of Australia

Many native animals are now close to extinction

According to the Australian Depart of the Environment's List of Threatened Fauna many Australian native animals are endangered and threatened with extinction. Foe example ; the Koala is listed as vulnerable , the Cassowary as endangered and the Gouldin Finch as critical.

  Critical Endangered Vulnerable
Fish 7 16 24
Frogs 5 14 10
Reptiles 8 17 34
Birds 9 47 62
Mammals 5 34 55
Other 23 17 11
Total 57 161 196

 


Extinct Animals of Australia

Many native animals became extinct since humans arrived

Since the arrival of European settlers in 1776 Australia has lost:

  • 7 of the 700 known species of birds
  • 19 of the known species of mammals

 

The Tasmanian Tiger is an example of an animal that went extinct in only the last 100 years or so, It was hunted into extinction. The last tiger died in captivity in 1927.


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