The Australian Megafauna
The First Australians
Somewhere in the region of 65,000 to 40,000 years ago, the ancestors of today’s Aborigines completed a risky and daring sea voyage across the Timor Sea to what they thought was just another South Asian island. Little did they know that in fact they had stumbled across a huge continent that had remained isolated for over 40 million years. With the first printing of human feet on the Australian coast, the fortunes of both the people and the wildlife changed forever.
As well as arriving in Australia via the tiny island of Timor, humans may have actually walked into the great southern continent via New Guinea. But how could humans have walked from New Guinea to Australia? Well, at the time, huge polar ice caps engulfed much of the Northern Hemisphere, trapping most of the world’s water. Consequently sea levels across the globe were between 100-300 feet lower than today, creating new land that plants and animals could colonise wilfully. Sometimes this newly uncovered ground formed ‘land bridges’ between previously unconnected places.
We’re not entirely sure whether the first pioneering voyagers made their journey at a time of normal or low sea level, it’s likely that they took advantage of low sea levels, so as to ease their crossing into the new land. But a sea voyage would have been just as favourable under normal sea level conditions because the currents and monsoon winds promote southward and eastward travel towards Australia. Most scientists today think that it was a sudden rise in sea levels that compelled human being to move from South East Asia, as previously habitable land was gradually sinking beneath the waves. Small groups of humans would have pushed ever onwards seeking new islands to call home.
The fact that the first Australians were the only large species to successfully cross the Timor Sea into Australia suggests that they were definitely not accidental castaways like the tiny rodents that had come before. These were highly sophisticated, totally indistinguishable from us in both body and mind. They possessed a complex culture, a complex language and all the skills needed to build, sail and navigate an ocean going craft to a specific destination.
The first Australians not only stumbled across a huge uninhabited continent, but a land where wild beasts never glimpsed by human eyes before roamed far and wide. They had indeed arrived in a land of mighty and ferocious beasts...
Australia in the Pleistocene
A New World, and a New Landscape
Like an Alien Planet
With the exception of a few species of rats and mice, Australia’s native mammals are either marsupials or the egg laying monotremes. The Australia of today is virtually devoid of any large native mammals, apart from a few kangaroos, but once, not all that long ago it boasted a much more spectacular fauna. There was a whole range of giants that are now totally extinct, such as carnivorous rat like kangaroos to one tonne monsters that resembled giant wombats, there were giant echidnas, and also all the more bizarrely a small cast of marsupial predators that bore an eerie resemblance to both the big cats and the wolf.
But monstrous marsupials were not the only wonders in store for the first Australians. The great southern continent also boasted an impressive menagerie of giant flightless birds, some of which still survive today. There was one particular kind of flightless bird that would have totally astounded the first Australians, to us it would have looked like a huge overgrown goose, and indeed modern scientists have given it the apt nickname ‘demon duck of doom. But perhaps the most frightening animals of all were the collection of giant reptiles that stalked the landscape, including the largest lizard to ever walk on the face of the Earth.
The landscape of ancient Australia would have presented those first human pioneers with a bit of a challenge, as they were mostly used to dense rainforests. In Australia they found themselves in open savannah and ‘dry jungle’ covering the exposed flat-lands of the continental shelf. The very flat terrain was prone to regular flooding, so some areas were covered in grass like sedges. Patches of trees dotted the grassland here and there- mainly Eucalyptus, Callitris and Casuarina. Additionally there were also swathes of dense wood, comprising of dry deciduous trees and vine-thicket communities, where grass was almost totally absent. While modern marsupials like the kangaroos grazed on the savannahs, many of the enormous prehistoric species browsed and thrived in the vine-thicket forests. Also, for around 6 million years Australia has been subjected to regular bush fires mainly as a result of the increasing aridity of the climate caused by the Ice ages. This savagely dry climate encouraged the evolution of fire and drought resistant plants such Acacia, Eucalyptus and Spinifex grasses.
I shall now profile a few of the most famous of Australia’s long lost megafauna, and I shall start with the biggest of them all...
The Biggest Marsupial of all Time
Diprotodon was a colossal creature, at roughly the size of a white rhino; it was the largest marsupial ever to be glimpsed by humanity and indeed the largest ever to have existed. The largest males weighed in at around 2.5 tons, it used to be thought that there were many different species of Diprotodon, due to the abundance of fossils that resembled each other but varied greatly in size. It seems more likely though, that they all belonged to just one species, with the largest fossils representing the huge males, and the smaller ones representing the females and young. The largest males stood around 5 feet at the shoulder and measured 10 feet from nose to tail; the skull alone was almost 3 feet long.
It’s a wonder that these creatures could even hold their massive heads up, but in order to make it lighter, they possessed two large, empty spaces in its skull, similar to an elephant. The skull also had a double structure, with an outer layer of bone to which the massive jaw muscles were attached, and an inner layer to hold and protect the brain. But whereas elephants have a relatively large brain, making them probably the most intelligent herbivorous mammal on the planet, the Diprotodon’s brain was very small.
Of all the large herbivores living in Australia during the Pleistocene epoch, Diprotodon was the commonest. Females have even been found with the remains of babies in their pouch, and fossilised footprints were found at Lake Callabonna in the south of the continent. The footprints have impressions of fur preserved around the foot, so it was likely they were much hairier than a rhino. The footprints also tell us that it didn’t walk or trot like a rhino either, but instead paced a bit like how a camel does, moving both feet on one side of its body at the same time. The animal that created the tracks at Callabonna was travelling at a rather leisurely 6 mph. Diprotodon though, was capable of putting on a short burst of greater speed when required, such as when they had to escape danger, but it wasn’t really built to be effective at long distance running.
More finds from Lake Callabonna help to at least give us some sort of insight into the Diprotodon diet, as several skeletons have been uncovered with the remains of their last meal still preserved in the stomach. Apparently they had been eating saltbush, which is quite a tough plant, and probably wouldn’t have been eaten regularly by Diprotodon, suggesting that these individuals were desperate, and may have ultimately succumbed to starvation during a drought.
A Giant Kangaroo
Giant Short Faced Kangaroo
The giant short faced kangaroo (Procoptodon goliah) was the bulldog of the kangaroo, and indeed the marsupial world, being far more robustly built than any modern kangaroo. Its skull was quite short and deep, giving it at first glance, an oddly human like appearance, but the kangaroo’s jaw was ideal for its needs, providing increased chewing force for the jaw muscles. It stood roughly six and a half feet tall and measured ten feet from nose to tail.
In order to postulate how exactly this enormous creature moved and behaved we must look at the red kangaroo which is very similar in terms of height and length, and possibly behaviour. Like the red, the short faced would have held its body horizontal to the ground, and would have avoided hopping on steep or rocky terrain, preferring flat ground. However, in stark contrast to living kangaroo’s the short faced only had a single toe on each of its hind feet. It may though, have been more bipedal than other kangaroos, electing to move about on two legs exclusively, but that’s just speculation.
The short faced kangaroo’s teeth indicate that it was a browser. It probably tugged down branches of overhanging acacia trees and pulled branches off saltbush trees at about chest height or maybe even propped itself up on to its tiptoes and tail in order to reach special treats higher up the boughs.
The Marsupial Predators
The Marsupial Lion's Bite
An interesting article that provides evidence that marsupial lion may have possessed the most powerful bite of any known mammal dead or alive.
The Marsupial Predators
Compared to most other parts of the world, Australia was a little light on numbers when it came to mammalian predators, but in terms of oddities, they are clear winners. The largest of the mammalian predators was the marsupial lion otherwise known as Thylacoleo carnifex. In appearance and habits it had many similarities to the big cats, such as retractable claws; hence why it was called a lion by scientists. But the marsupial lion had a rather interesting trick up its sleeve, which no real cat possessed. The thumb of the forepaw bore a huge and formidable curved claw, much larger than the others. The exact function of this long claw is not fully understood but it might have been used as a slashing tool for inflicting deep wounds on its prey, perhaps in a similar way that the Velociraptors’ used their large claws on their hind legs to kill in the ‘Jurassic Park’ film series.
Even more remarkable than the raptor like claws were the ‘lion’s’ teeth; instead of the large canine teeth typical of placental carnivores, the marsupial lion possessed enlarged incisors which gave it a rather comical bucktoothed appearance. Its molars had very long, blade like edges that sheathed past each other to give it efficient slicing weapons. Its huge jaw muscles provided the power for this fearsome bite.
Its total length from nose to tail was just shy of 6 feet and recent estimates indicate that its weight was around 200Ib, so roughly that’s equivalent to a modern jaguar or a large wolf. But with its chunky stature the marsupial lion would have outmuscled any similar sized cat. In another piece of evolutionary magic, the ‘lion’ also possessed a cat like pelvis, adapted for running, crouching, stalking and pouncing. The marsupial lion’s powerful but flexible forelimbs could rotate in the way that s cat can rotate its paws, or to put it another way, similar to how we can rotate our hands. Imagine being able to rotate your entire arm in the same way.
So, while the marsupial lion only really resembled the cats in a very slight way. There was another mammalian carnivore roaming Australia that did eerily resemble a distantly related animal living elsewhere. This was the Thylacinus cynocephalus, or ‘Tasmanian wolf’ to give it its common name, on account that it bore an uncanny and faithful resemblance to not just the wolf but the canine family in all. The ‘wolf’ was called Tasmanian by the British, because by the time Captain Cook ‘discovered’ the continent in the 18th Century, Thylacinus had been extinct on the Australian mainland for over 3000 years, and only survived on Tasmania, which it would continue to do so until the 1930’s when it suffered its final extinction . Their extinction on the mainland was probably caused through having to compete with the first ‘real’ dogs or dingoes that were brought to Australia by humans. Incidentally the Tasmanian devil also suffered extinction in Australia in a similar way and at the same time. But fortunately for us today, it still survives to be marvelled at by tourists.
Thylacinus survived long enough in Tasmania for it to be filmed by curious Europeans. The films depict an animal which looked and trotted like a dog. This is a remarkable example of convergent evolution (when two completely unrelated organisms evolve similar traits) considering the fact that the wolf is more closely related to us and whales than it is to the marsupial variety. However, the differences between the two ‘wolves’ became apparent when observations were made of the tail and jaws. Thylacinus had a tail which was much thicker at its base than a real dog and its jaws could open much wider than a real dog. The pups were carried in a backwards facing pouch and the hind end of the animal back’s was covered with around twenty dark, parallel stripes. These stripes have often led to people referring to the ‘wolf’ as the ‘Tasmanian tiger’. Remarkably this odd dog like marsupial predator survived right up until the 1930s, by this time competition with real dogs and humans had taken its toll. The last known individual died in Hobart Zoo in 1936.
The Thylacine on Film
The Reptilian Giants
Australia not only provided home for giant mammals, but also perhaps more frighteningly giant reptiles, some of which were the biggest to stalk the Earth since the dinosaurs. Some of these monstrous reptilian giants such as the saltwater crocodile still survive today. But now I shall proceed to profile the saltwater crocodile’s formidable prehistoric relatives.
The biggest of these was an enormous goanna lizard called Megalania prisca or the giant ripper lizard. It was the largest lizard that has ever lived and resembled a hugely scaled up Komodo dragon. While Komodo Dragons themselves can grow to an impressive ten feet in length, Megalania routinely grew to double that size and weighed an impressive 880Ib.
Surprisingly Megalania’s closest relative is not the Komodo, but a smaller Australian goanna species known as the perentie, but due to its sheer size Megalania was probably more like a Komodo both in appearance and behaviour. It probably hunted by day, even during the worst wet season, as it was totally impossible for it to be active after nightfall due to its cold blooded metabolism and size. After dark, it would have probably sought out resting places under the shade of a tree canopy to minimise heat loss during the cool of the night.
The Komodo dragon is known as a fairly regular man-eater; therefore the first Australians may have found themselves on the menu of Megalania. Their hunting strategy was simple; try to knock their prey to the ground and then simply tear it to pieces. The armoury required to accomplish this were long powerful claws and a fearsome set of large, curved and serrated teeth. If Megalania somehow failed to dispatch its victim in the first attack then it had the luxury of a secret weapon. Its saliva, just like the Komodo was full of dangerous bacteria that caused any wounds to fester and go septic, making death inevitable one way or the other. Like the Komodo, Megalania would have tracked its stricken victim, either simply waiting for it to die or attacking it again.
It’s likely that Megalania perceived the world in a similar way as the Komodo does, so scent was its primary method of detecting food. Using its long, forked tongue and a scent organ in the roof of the mouth known as the Jacobsen’s organ, it was probably capable of smelling a rotting carcass from over 7 miles away. Its vision was good allowing it to see clearly up to a distance of 984 feet, but was probably better at viewing moving objects than stationary ones. Its hearing probably had quite a limited range, preventing it for example from detecting a low pitched human voice or a high pitched scream.
Another large monstrous reptile was a large land crocodile known as Quinkana. It was a formidable carnivore weighing in excess of 400Ib’s. Its snout was deep and box life, for want of a better description, making it quite unlike any living crocodile. Its teeth were similar to those of Megalania, except that they were serrated along both edges. There was also a giant snake that grew in excess of 25 feet called Wonambi. As well as being an extremely long snake it was also very broad measuring about a foot across. Its head alone was the size of a shovel, and was just as broad as the body. Its mouth was filled with hundreds of tiny teeth, suggesting that it specialised in taking prey up to the size of a wallaby. It probably caught its prey through ambush, probably waiting by waterholes or along pathways in rocky areas and then killing it through constriction.
While most of Australia’s giant reptiles were predators, there were some rather more gentle giants that roamed the prehistoric landscape. This was a giant land turtle known as Meiolania, an enormous 500Ib reptile that had elephant like feet that were similar to the living Galapagos giant tortoises. But in almost every other way, they were totally different to any other turtle or tortoise living today. Their carapaces were much lower and broader than typical land tortoises. Their tails were heavily armoured and spiked with bony rings. The head which could not be retracted was also heavily armoured. But its most striking feature was its two horns that coincidentally resembled those of cattle.
A Giant Flightless Duck
Australia is still one of the few places in the world, where giant flightless birds are common. The famous emu is today a symbol of modern Australia alongside the kangaroo, but back in prehistory it had to share its domain with a much larger and altogether stranger relative.
Genyornis was an odd looking giant flightless bird that bore an uncanny resemblance to ducks and geese. This resemblance was no accident, as it was actually quite closely related to them, and only distantly related to the emu and its kin known collectively as ratites. The close relationship to wildfowl led to scientists giving it a rather imaginative nickname ‘the demon duck of doom’. At around 7 feet tall, Genyornis was roughly the same size as a male ostrich, but more than twice the weight, tipping the scales at around 450Ib’s. Being such a heavily built bird meant that Genyornis probably wasn’t capable of moving quickly like an ostrich or emu. Its wings were tiny and largely useless, apart from maybe flapping them as a display to rival mates or mates.
Its most distinguishing features were its enormous beak and huge jaw muscles. The entire beak and skull structure actually resembled that of birds that crack nuts or eat fruits such as parrots. Genyornis was almost certainly a vegetarian, browsing in the higher echelons of trees and shrubs like a giraffe. Being a bird though, it lacked teeth and thus had to swallow stones to help grind up the food in its gizzard. Some palaeontologists have suggested that Genyornis may have been an occasional scavenger or even grabbing small prey when it could, but that’s just speculation.
So that concludes my profile on the Australian megafauna that the first human settlers may have encountered some 40,000 years ago or more. The next Hub in the series will explore the weird and wonderful creatures that greeted the earliest colonisers of Earth’s isolated islands, such as Madagascar, Hawaii and New Zealand.
More to follow...
Highly Recommended Links
- The Future Eaters - Home page of the TV documentary series
The home page of the TV adaptation of Tim Flannery's excellent book 'The Future Eaters'.
Three Highly Recommended Books
Questions & Answers
what did the giant short-faced kangaroo eat?
According to dental analysis of its teeth, it seems that the giant short-faced kangaroo was exclusively a browser, so would have lived on a diet of leaves from trees and shrubs.