What is so different about Australia?

Well, for starters:

• it is the only continent (and one of the only two countries - the other being New Guinea) in the world to still have all three of the major groups of mammals: monotremes (egg-layers), marsupials and placentals
• half its mammal species are marsupials
• its large grazers and browsers are all marsupials or birds, mostly either running or hopping on two legs
  
• it is the only country in the world to have kangaroos (although New Guinea and some neighbouring islands have wallabies), koalas, wombats numbats, platypus, lyrebirds and many other strange and fascinating creatures
• it shares with New Zealand the world's only 'glow worms' (they are actually fly larvae - and not the same as the 'glow worm' of the northern hemisphere, which is the larva of the firefly, which is actually a beetle, in a family that also occur in Australia) - these insects produce an extremely efficient kind of light to attract their prey, looking like starry skies in caves or under overhanging cliffs
  
• it is the only continent other than Antarctica to NOT have native hoofed animals, or native terrestrial Carnivora (dogs, bears, cats, weasels etc., but we do have seals and sealions) - the dingo appears to have arrived from Southeast Asia only about 4,000 years ago, probably with Indonesian traders
• it is probably the birthplace of the world's songbirds, and shares with New Zealand some songbirds with primitive characteristics
• lyrebirds, arguably the world's best mimics, occur only here
• some of our frogs have bizarre breeding habits - e.g. the gastric brooding frog (now apparently extinct) and the hip pocket frog
• we have most of the world's ten most venomous snakes (in terms of toxins applied to mice) but not necessarily the most dangerous (which is a function also of behaviour and habitats of snakes)
  

And how did it become so different? Australia has been the most isolated of all continents since splitting from the great supercontinent Gondwana about 50 million years ago, and the evolution has had a chance to produce many different ways of coping with the Australian environments.

Evolutionary/biogeographical history of Australia

Australia was once part of the great southern super-continent Gondwana (which included what we now know as South America, Africa, Madagascar and India as well as many of what are now smaller islands).

About 50 million years ago Australia and New Guinea jointly drifted away from Antarctica, this event being the final breakup of the huge southern continent Gondwana.

Australia broke away before any hoofed animals, cats, bears, monkeys, rodents or other placental mammals had a chance to get even close to it, but did have monotremes (egg-laying mammals) and marsupials (mammals whose young are born at a very immature stage and attach firmly to a teat inside a pouch or between protective flaps of skin for the next few weeks). As it drifted northwards, Australia was isolated from other continents for many millions of years.

Thus its fauna and flora include many species whose ancestors were in Gondwana, some of which, like the freshwater turtles, tree frogs and land snails, still somewhat resemble their cousins across the sea, while others, like the kangaroos, platypus and lyrebirds, are remarkably different from animals on any other continent.

MORE ON THIS COMING SOON!

Meantime see:
Evolutionary history of freshwater fishes and crustaceans of southeast Australia: conservation, genetics, and geology
Phylogenetic Systematics and Bioinformatics, Australian National University (reptiles, invertebrates, plants)
Geological History and Australian Flora
Australia's oldest amphibians

Fish

Fish are vertebrates that live their entire lives in water, breathe through gills and don’t go through the kind of dramatic life-change that amphibians do (although some, like the lungfish, have developed ways of occasionally breathing in air).

Australia’s freshwater fish have all evolved relatively recently from marine ancestors – we don’t have the families common in other continents with a long evolutionary history of freshwater life.

No attempt will be made here to cover the tremendous diversity of fish, just a few points of interest here:

The Australian lungfish, a freshwater species capable of breathing in air, is considered a ‘living fossil’ and is found in some of Queensland’s rivers. Only five other species occur worldwide, all in Africa and South American waters. It is strictly protected.

The eels in Australian rivers start their lives near New Caledonia and other part sof the southwest Pacific, make a journey to Australia where they live for 12 years or more in the rivers of the east coast, then find their way back to their birthplace to breed. There are usually at least a couple resident on the Araucaria property.

The world’s largest fish, the whale-shark, visits the western coast each year. Carefully-controlled diving near these huge creatures (which feed only on plankton) is a popular tourist activity at Ningaloo.

The world-famous Great Barrier Reef harbours a vast and fascinating diversity of fish, some of which featured in the popular animation film ‘Finding Nemo.’

The strange leafy sea-dragon, related to sea-horses, can sometimes be seen by divers near Kangaroo Island and other parts of the southern coastline.

Further information on fish:

Freshwater fish

Marine fish

Invertebrates

They deserve many pages of web space, ranging from microscopic mites of the leaf litter and plankton in the sea, through the amazing reef-building corals and 'cold-light' producing glow worms, bright and beautiful butterflies, to giant earthworms and giant clams - thousands upon thousands of species, and many we probably do not yet know the existence of.

More details will be added to this page in the future

Meantime see:

Insects

A useful compact reference is: Zbrowksi, P. and Storey, R. (1995). A Field Guide to Insects of Australia. Reed Books, Kew (an amazing amount of detail packed into a compact paperback book)
CSIRO produces two massive (and expensive!) volumes for the identification of Australian insects
There are also various useful guides to Australian dragonflies, butterflies, moths, ants, stick insects (phasmids) and other insects)
e.g.

Spiders

Australian spiders include the 'true' spiders and the 'primitive' spiders.

The 'primitive spiders have jaws which point downwards, meaning that to bite they need to rear up and strike downwards. Australia's most dangerous spiders, the funnelwebs, are in this group, and also the trapdoors. To keep the danger in perspective though, there have only been 14 recorded deaths by funnelwebs in the history of white settlement.  Most of these have occurred in Sydney, where funnels aresometimes built in gardens and inadvertantly disturbed.

The 'true' spiders include all the others, including the infamous redback (probably a form of black widow, responsible for a similar number of deaths but none since the introduction of antivenine in the 1950's), the large and impressive golden orb weavers, the hunstman and wolf spiders that chase their prey instead of snaring it, and many others, some quite beautifully coloured. The vast majority are never dangerous, but some can give a painful nip.

Other invertebrates include:

    * Sea-stars, sea-urchins and sea-cucumbers
    * Molluscs - snails, slugs,cowries, oysters, clams, octopus ...
    * Earthworms and leeches
    * Flatworms - not related to earthworms (they're just called worms because they're long and thin and lack legs)
    * Jellyfish, anemones and corals
    * Sponges
    * Various other groups of small creatures