Australia does mammals differently.
We have mammals that lay eggs.
Mammals that carry tiny young in pouches.
Mammals that glide between trees.
Mammals covered in spines.
Mammals that hop rather than run.
And one particularly strange animal that looks as though somebody assembled it from spare parts.
For millions of years, Australia’s isolation allowed its wildlife to evolve largely apart from the mammals living on other continents.
The result is extraordinary.
Many Australian mammals are found nowhere else in the wild.
Some belong to ancient branches of the mammal family tree.
Others evolved to fill roles occupied by completely different animals elsewhere in the world.
Australia’s mammals aren’t simply unusual.
They tell the story of a continent that spent millions of years doing things its own way.
Australia Wasn’t Always an Island Continent
To understand Australia’s unusual mammals, we need to go back a very long way.
Australia was once part of the southern supercontinent Gondwana.
Gondwana included land that would eventually become Australia, Antarctica, South America, Africa, India and other regions.
Over immense periods of geological time, the continents separated.
Australia eventually broke away from Antarctica and moved north.
For tens of millions of years, it became increasingly isolated.
That isolation mattered enormously.
Animals evolving in Australia were largely separated from the mammal populations developing elsewhere.
Evolution had its own Australian laboratory.
And the results became wonderfully strange.
Australia’s Mammals Followed a Different Path
Most of the world’s familiar land mammals are placental mammals.
Dogs.
Cats.
Horses.
Elephants.
Cattle.
Humans.
Their young spend a relatively long period developing inside the mother’s uterus, supported by a complex placenta.
Australia’s native terrestrial mammal fauna developed very differently.
Marsupials became extraordinarily diverse.
Even more remarkably, Australia retained monotremes — mammals that reproduce by laying eggs.
That alone makes Australia’s mammal story exceptional.
Meet the Monotremes
There are only five living monotreme species in the world.
Australia has the platypus and the short-beaked echidna.
The other living echidna species occur in New Guinea.
Monotremes are mammals.
They have fur.
They are warm-blooded.
Mothers produce milk for their young.
But they lay eggs.
That combination seems so strange because almost every mammal we’re familiar with gives birth to live young.
Monotremes are survivors from a very ancient branch of mammal evolution.
And two of their most famous representatives are still living in Australia.
The Platypus Confused Europe
When specimens of the platypus reached Europe around the end of the 18th century, the animal looked so improbable that some people suspected a hoax.
Understandably.
It had a broad bill.
Webbed feet.
Dense fur.
A flattened tail.
And it laid eggs.
Surely somebody had stitched several animals together.
They hadn’t.
Australia had simply produced the platypus.
More than two centuries later, it still looks slightly made up.
The Platypus Gets Stranger the Closer You Look
The bill of a platypus isn’t simply a duck-like mouth.
It contains specialised receptors capable of detecting tiny electrical signals produced by the muscles of prey.
When a platypus dives, it closes its eyes, ears and nostrils.
It can then use its extraordinary bill to locate worms, insect larvae and other prey underwater.
As though that wasn’t enough, male platypuses have a spur on their hind legs capable of delivering venom.
So we have an egg-laying, electroreceptive, venomous mammal with webbed feet and a bill.
Sometimes Australian wildlife really does sound like somebody was showing off.
Platypus Mothers Don’t Have Nipples
The reproductive story gets stranger.
Female platypuses lay eggs in a burrow.
When the young hatch, they drink their mother’s milk.
But platypuses don’t have nipples.
Milk is secreted through specialised areas of the mother’s skin and collects in grooves where the young can lap it up.
It is a very different system from the one used by most mammals.
Yet it works.
Platypuses have survived for millions of years.
Clearly nobody told them they were doing mammals incorrectly.
Then There Is the Echidna
If the platypus looks assembled from several animals, the echidna isn’t far behind.
It has spines like a porcupine.
A long snout.
Powerful claws.
A sticky tongue.
And it lays eggs.
The short-beaked echidna occurs across Australia in an enormous variety of habitats.
Forests.
Woodlands.
Grasslands.
Mountains.
Dry country.
It survives partly because it is remarkably adaptable.
Its diet consists mainly of ants and termites, which it digs out using strong claws before collecting them with its long sticky tongue.
A Baby Echidna Is Called a Puggle
Yes.
Really.
After mating, a female echidna lays a single leathery egg.
The egg is carried in a temporary pouch-like fold on her abdomen.
When it hatches, the tiny young — commonly called a puggle — remains protected while it develops.
Eventually there is a fairly obvious problem.
Spines.
Once the young echidna starts becoming prickly, carrying it against your body becomes considerably less appealing.
The mother leaves the youngster in a nursery burrow and returns to feed it until it is independent.
Motherhood has limits.
Apparently spikes are one of them.
Marsupials Took Over Almost Every Lifestyle
Australia’s marsupials deserve their own story — and they have one — but they are also central to understanding why Australia’s mammals are so unusual.
Marsupials diversified into an extraordinary range of forms.
Kangaroos became grazers.
Koalas specialised in eucalyptus leaves.
Wombats became powerful burrowers.
Possums took to the trees.
Gliders developed membranes allowing them to sail between them.
Quolls became predators.
Bilbies and bandicoots became diggers and foragers.
Tasmanian devils became powerful scavengers and hunters.
Instead of one basic marsupial body type, evolution produced animals capable of occupying completely different ecological roles.
Australia Once Had Even Stranger Mammals
Modern Australia gives us only a glimpse of the mammal diversity that once existed here.
During the Pleistocene, Australia was home to enormous animals known collectively as megafauna.
There was Diprotodon, the largest known marsupial.
Imagine something vaguely wombat-like but roughly the size of a rhinoceros.
There were giant kangaroos.
Huge browsing marsupials.
And formidable predators.
One of the most extraordinary was Thylacoleo, often called the marsupial lion.
It wasn’t actually a lion.
It was something distinctly Australian.
A powerful carnivorous marsupial equipped with formidable teeth and claws.
The Thylacine Survived Much Longer
Another famous Australian mammal disappeared far more recently.
The thylacine, or Tasmanian tiger, was a striped carnivorous marsupial.
Despite the name, it wasn’t a tiger.
Nor was it closely related to dogs, although its body shape looked surprisingly dog-like.
That resemblance is an excellent example of convergent evolution — unrelated animals evolving similar features because they occupy similar ecological roles.
Thylacines disappeared from mainland Australia thousands of years ago but survived in Tasmania.
The last known captive thylacine died at Hobart’s Beaumaris Zoo in 1936.
Its disappearance remains one of Australia’s most famous modern extinctions.
And despite countless reported sightings since then, there is no verified evidence that the species survives today.
The Dingo Is Different Again
The dingo is one of Australia’s best-known mammals, but its history here is very different from that of the platypus, echidna or marsupials.
Dingoes didn’t evolve in Australia over tens of millions of years.
Their ancestors arrived much more recently, probably several thousand years ago.
Exactly how and when they arrived remains an area of continuing research.
Once established, however, dingoes became Australia’s largest terrestrial predator.
They adapted to environments ranging from deserts to forests and became deeply connected with many Aboriginal cultures.
Today they occupy a complicated place in Australian life.
Native wildlife predator.
Cultural animal.
Top-order carnivore.
Livestock threat.
Wild dog.
The dingo doesn’t fit neatly into one box.
Very Australian, really.
Australia Has Native Rodents Too
With all the attention given to marsupials and monotremes, Australia’s native rodents are often forgotten.
But Australia has numerous native rats and mice.
They aren’t simply descendants of the black rats and house mice introduced after European settlement.
Native rodents reached Australia naturally long before Europeans arrived and evolved into distinctive species.
Some adapted to deserts.
Others to forests and wetlands.
There are hopping mice with long hind legs.
Tree rats.
Water rats.
And species found only in particular parts of Australia.
They may not appear on many postcards.
But they’re part of Australia’s unique mammal story too.
Rakali – Australia’s Native Water Rat
One particularly impressive native rodent is the rakali, also known as the Australian water rat.
Rakali live around rivers, lakes, wetlands and coastal areas.
They are strong swimmers.
Their partially webbed hind feet and thick tail help them move through the water.
They feed on fish, crustaceans, frogs, insects and other prey.
With their waterproof fur and aquatic lifestyle, they fill a very different ecological role from the introduced rats Australians usually picture.
Seeing one swimming across a river can be quite a surprise if you don’t know what you’re looking at.
Australia Has Plenty of Bats
Australia’s only native mammals capable of true powered flight are bats.
And we have plenty of them.
Tiny insect-eating microbats emerge after dark and consume enormous numbers of insects.
Flying foxes are much larger.
They travel considerable distances searching for flowering and fruiting trees.
They also perform an important ecological job.
Flying foxes pollinate flowers and spread seeds across the landscape.
Some native forests depend on animals moving pollen and seeds over large distances.
A noisy flying-fox camp might not always make nearby humans happy.
But ecologically, these animals are doing important work.
Some Australian Mammals Learned to Glide Instead
Bats evolved true flight.
Several Australian marsupials found another solution.
Gliding.
Sugar gliders, squirrel gliders, yellow-bellied gliders and greater gliders use membranes of skin stretched between their limbs to move through the forest canopy.
They launch from trees and glide through the air, steering towards another trunk.
It’s an efficient way of moving through forests without descending to the ground.
Greater gliders can travel impressive distances between trees.
Watching one sail silently through a forest at night is a reminder that Australian wildlife becomes a very different world after dark.
Australia Has Mammals Most Australians Never See
Some of our most interesting mammals are rarely encountered.
Small marsupials such as dunnarts, antechinus, potoroos and bettongs can live remarkably secretive lives.
Many are nocturnal.
Some occupy small ranges.
Others have become uncommon because of habitat loss and introduced predators.
You could live your entire life in Australia and never see many of them in the wild.
That doesn’t make them unimportant.
Small mammals dig soil.
Eat insects.
Spread fungi and seeds.
Become prey for larger animals.
And contribute to healthy ecosystems in ways that aren’t always obvious.
The famous mammals get the postcards.
The little ones quietly keep doing the work.
Digging Mammals Help the Australian Landscape
Bilbies, bettongs, bandicoots and other digging mammals once turned over enormous amounts of Australian soil.
Searching for food created small pits and disturbed patches of earth.
That activity mixed soil.
Trapped leaves and organic matter.
Helped water penetrate.
Created places where seeds could germinate.
Ecologists sometimes describe these animals as ecosystem engineers.
Their digging changes the environment around them.
When populations of digging mammals disappear, the effects can extend beyond the animals themselves.
Sometimes saving a small mammal can also help restore the landscape it once maintained.
Introduced Mammals Changed Everything
Australia’s isolation produced unusual mammals.
Then humans brought animals from elsewhere.
Some were deliberately introduced.
Others arrived accidentally.
Cats.
Foxes.
Rabbits.
Black rats.
House mice.
Pigs.
Goats.
Deer.
Horses.
Camels.
Cattle.
Sheep.
Many became part of Australian life.
Some also caused enormous ecological damage.
Predation by cats and foxes has been particularly devastating for small native mammals.
Animals that had evolved without these efficient introduced predators suddenly faced threats they were poorly equipped to handle.
Australia Has Lost Too Many Mammals
Australia’s mammal story isn’t entirely something to celebrate.
Since European settlement, Australia has suffered an exceptionally high rate of mammal extinction.
Small and medium-sized mammals have been particularly vulnerable.
Habitat destruction played a role.
Introduced predators played a major role.
Changed fire patterns, grazing and competition added further pressure.
Species that had survived for thousands or millions of years disappeared remarkably quickly.
The thylacine became the most famous loss.
It wasn’t the only one.
And without conservation, it won’t be the last.
Island Sanctuaries and Fenced Reserves Are Bringing Some Back
There is good news.
Conservation programs around Australia are working to restore threatened mammals.
Predator-free islands provide safe habitat.
Large fenced sanctuaries remove cats and foxes.
Captive breeding programs rebuild populations.
Animals can then be reintroduced into areas where they disappeared generations ago.
Bilbies.
Bettongs.
Bandicoots.
Quolls.
Other threatened mammals.
In some places, animals are returning to landscapes where they haven’t been seen within living memory.
Australia cannot undo every extinction.
But we can prevent more.
Australia’s Mammals Help Define the Country
Few countries are represented so strongly by their native mammals.
The kangaroo stands beside the emu on Australia’s coat of arms.
Koalas became international symbols of Australian wildlife.
The platypus appears on our coins.
Echidnas are recognised almost instantly.
Wombats, quokkas and Tasmanian devils have enthusiastic followings around the world.
But their importance goes beyond tourism and national symbols.
These animals are products of Australia’s deep natural history.
They belong to this landscape in ways measured not in centuries, but millions of years.
Familiar Doesn’t Mean Ordinary
Perhaps Australians sometimes take our mammals for granted.
A kangaroo standing in a paddock barely earns a second glance in some parts of the country.
An echidna crossing a road is interesting, but not unbelievable.
A possum on the roof is mostly annoying when you’re trying to sleep.
Yet to someone visiting from another part of the world, these animals can be astonishing.
And they should be.
An egg-laying mammal detecting electrical signals underwater is astonishing.
A kangaroo carrying a tiny developing joey is astonishing.
A glider sailing between eucalyptus trees is astonishing.
We’ve simply grown used to them.
Why Australia’s Mammals Are Different
Australia’s mammals are the result of deep time.
Continents moved.
Oceans opened.
Climates changed.
Forests expanded and contracted.
Species evolved.
Others disappeared.
Through it all, Australia’s long isolation allowed animals to follow evolutionary paths that were very different from those taken elsewhere.
That’s why our mammal fauna feels so distinctive.
It isn’t one strange animal.
It’s an entire history of isolation, adaptation and survival.
Australia’s Unique Mammals – Millions of Years in the Making
Australia didn’t set out to become the country with the world’s strangest mammals.
Geography did most of the work.
Our continent separated.
Our wildlife became isolated.
And evolution carried on.
The result was the platypus.
Echidnas.
Kangaroos.
Wombats.
Quolls.
Bilbies.
Gliders.
Dingoes.
Bats.
Native rodents.
And hundreds of other mammals, living and extinct, that form part of Australia’s natural story.
Some lay eggs.
Some raise impossibly tiny young.
Some dig.
Some hop.
Some fly.
Some glide.
And some are so strange that the first Europeans who saw them had difficulty believing they were real.
Millions of years later, they’re still here.
At least some of them.
And protecting what remains means future Australians will still be able to look at our wildlife and think exactly what people have thought for generations.
Only in Australia.
