Thylacoleo

The Marsupial Lion!

Like most environments, Australia has its fair share of herbivores and carnivores; both big and small, ranging from the common, to the strange, to the downright bizarre. While other continents were sharing many of their predators amongst themselves (through the appearance of land bridges and the like), Australia 's isolation caused many of its normally docile herbivorous species to turn carnivorous. These often evolved body shapes similar to more famous northern-hemisphere carnivores such as wolves and lions.

These similarities were brought about by an evolutionary mechanism called ‘convergent evolution' (when two species, not even remotely related, evolve features or body types similar to each other because there is an environmental need for what ever it is that makes them similar in the first place…or simply put, form follows function). Australia 's most famous example of convergent evolution is the ‘Tasmanian tiger' or Thylacine . The tiger stripes appeared because Thylacines lived in thick forest and the stripes helped it blend in…just like those found on a true Tiger.

The Thylacine is far from the only example however. Australia has dozens of such species, and easily the most dangerous of these was Thylacoleo - the Marsupial lion!

The earliest published reference to Thylacoleo was in 1838, but the most famous description appeared in 1858 by renowned naturalist and paleontologist, Sir Richard Owen (most famous for penning the name Dinosauria), who described these carnivores as ‘the fellest of all predatory beasts'.

Several Thylacoleo remains have been found in recent years, not only around the Naracoorte caves area, but all over Australia - including the world famous fossil site at Riversleigh (Queensland), generating what could be a revival of interest in these most uniquely Australian carnivores. These finds have given us a much broader view of Thylacoleo , and has shown us that there were in fact more then one species of these odd predators, prompting scientists to christen the entire group Thylacoleonidae.

Largest and most recent is of course Thylacoleo carnifex (Thylacis- marsupial or pouched, leo –lion and carnifex- to slice flesh). This was a lioness-sized carnivore whose remains have been found across Australia and was probably the largest marsupial carnivore of the time. It's possum like feet and hands suggest it was a tree-climbing carnivore that lived a life style much like modern leopards (the marsupial leopard being a much more apt name). It lived during the late Pleistocene (roughly 40 000 years ago) with some believing its survived till today (visit www.thylacoleo.com for more information on this)

Thylacoleo has been under scrutiny since Sir Richard Owens first description. In fact many of his contemporaries doubted it was a carnivore at all, suggesting it was probably a large herbivore that fed on melons. It's only been recently that careful studies of the teeth have proven that it was indeed carnivorous, and this argument has been helped no end by the discovery of bones from animals such as kangaroos and wombats that are covered in bite and chew marks that perfectly match Thylacoleo's teeth.

 

 

An interesting question is from where did these carnivores evolve? What sort of hideous creature could give rise to the ‘fellest of predatory beasts”? DNA tests show its closest living relative are the wombats (Diprotodontid), and indeed shares many features with these tough little herbivores. This was always considered a possibility, though many claimed similarities between the Thylacoleonids and possums suggested these were their ancestors (similarities such as their feet could just be an adaptation for climbing trees -convergent evolution again)! The DNA tests however have cinched it, placing Australia 's top predator in with the wombats.

So how would a ‘killer wombat' kill? Well not only did Thylacoleo possess possum like feet; they also have an opposable thumb with a monstrous, sickle shaped hooded claw at the end (hooded claws can be sheathed like those found on most cats). The purpose of such a claw would have been to not only help the predator climb trees while carrying a meal in its mouth (again like a leopard), but would also help kill its prey, using wide, powerful sweeps of its claws, and its immensely powerful front arms to stab, tear and kill.

This idea also has its detractors as surveys of their limb bones suggest Thylacoleo had front arms far too long for climbing trees. They'd also make them look more like a Hyena then a lion. At the very least its likely Thylacoleo was partially arboreal, hauling its meal up a tree to safely snack on them away from prying eyes of other predators.

One interesting fact is that over the last hundred years or so, Thylacoleo seems to have been shrinking. The initial estimates of it being ‘lion' sized was disputed and rethought and rebuked till some had it weighing as little as around 40 kilos, a long way from the roughly 120 kilo lion. This has been proven to be complete rubbish, and in fact lion sized may have been being generous to the lions. A better comparison is to Smilodon-the saber toothed tiger.

Both were roughly the same size, with shortened backs and robust forelimbs. Both possessed off teeth-Smilodon its sabers and Thylacoleo its odd, forward jutting incisors?. Both show similarities in their feet, their molars had either disappeared completely or expanded to create huge “shearing' molars. Fossil bite marks on the ribs of prey animals seems to suggest both preferred to eat the internal organs of their prey then the tough flesh. And lastly both had mega-herbivores to contend with. Smilodon had all the famous Ice age herbivores like woolly mammoths and bison while Thylacoleo had 2 tonne Diprotodon (a giant wombat) and massive short-faced kangaroos to deal with. Both predators' bodies show the same adaptation for dealing and killing such large herbivores, and could be the very reason for the extinctions. No Mega-herbivores, no Mega-herbivore predators!

Another reason for its immense strength is that they're marsupials. Not only would a female Thylacoleo have to pull itself plus its carcass up the tree, but all the young it would be carrying in its pouch…they are marsupials after all! With this much weight, it's no wonder Thylacoleo was more muscled then Leopards that are living a possible similar life style!

But why did they die out? As mentioned before, the loss of the Mega-herbivores may have had something to do with it, though there are others. The appearance of not only the first humans, but Dingos may have brought about their extinction. Humans first arrived in Australia some 60 000 years ago while the Dingo has been here for just over 3 000 years. These time frames actually coincide with other extinctions such as mainland-based populations of carnivores like the Tasmanian devil ( Sarcophilus harrisii ) and Thylacines . These early Aborigines brought with them a new and devastating weapon, which they used to help them hunt and reshape the land…Fire! By burning off huge tracts of land, these early Australians would have removed much of the thick woodlands that both the large herbivores needed to eat and these ambushing predators needed to hide and stalk their prey with. There is some cave painting evidence that early Aborigines did indeed mingle with some of Australia's mega-fauna, and there's even rock paintings in the Northern Territory that seem to show a Thylacoleo … Though worn and fading, the painting shows a very cat-like creature and sadly suggests something else. Cave paintings seem to reflect the local environment these early humans lived in, and with only one (semi) confirmed rock painting this appears to tell us Thylacoleo was already a rarity in Australia . If common they should appear everywhere, like rock art of kangaroos, snakes- even turtles show up more then the massive Thylacoleo . Perhaps its absence is in itself evidence to their rarity or extinction. Until more evidence is unearthed as to why they went extinct, we'll just have to live with the fact that they're gone.

Thylacoleo however was far from the only member of the Thylacoleonidae. Similar inapperance, three sub families have appeared in the group, mainly based on the differences in their teeth. The first are the group Priscileo (ancient-lion) that at the moment has only 2 members. The earliest Thylacoleonid was Priscileo pitakantensis , found near Lake Pitakanta , South Australia . It lived during the late Oligocene. The second is P. roskellyae from early Miocene deposits at Riversliegh.

The Wakaleoninae (waka is an aboriginal word for ‘little' and of course Leo is for lion) are the third group and had similar body types, yet they differentiated in size (they were much smaller) and had shorter teeth. Newly unearthed fossils of a wakaleonid show teeth similar (though more primitive) to those in Thylacoleo, it is almost certain they are their direct ancestors (a point importantly established as before these new finds they were thought to be almost completely unrelated).

To date the only known Wakaleonids are Wakaleo alcootaensis ( Northern Territory ), W. oldgieldi ( South Australia ) and W. vanderleueri ( Northern Territory ). These are older and smaller then Thylacoleo and possess more primitive features.

It would seem that rather then somehow ‘justify' our own prehistoric species we should be waving them at the rest of the world and dancing a little jig. Far from being boring and lacking in any interesting carnivores we may well have had some of the most impressive mammalian predators of all time, though I like to point out that all land based carnivores, not matter how large, were nothing but a mere snack to a current day killer whale- possibly the most impressive mammalian predator of all time…except maybe for us!

 

The Devil lifts its head from its meal and gives out a growly, ghostly wail of a call. Looking about to make sure all is safe, it again lowers its' head, returning to its meal. With a crack it bites down and through the thighbone of the baby wombat. Not many animals dare disturb a feeding devil armed with a powerful bite and an equally nasty temper, a temper matched only by the Northern hemispheres fabled wolverines. Occasionally a shadowy figure tries to move into the area the feeding Devil is in, and is also greeted by the deep intense whiny grumble of the little carnivores' warning, and quickly backs away. Nonchalantly the devil goes about the business of finishing its meal, the sound of crunching, breaking bones echoing through the forest canopy.

Further on the night parts, releasing another predator into its chilled air. Dropping from its daytime resting place high in a tree, it hits the ground with an almost inaudible ‘thump' then slinks away, easily missed in the ebony grip of this moonless nights embrace. Truly a ghost of the night, set to deliver terror to the nocturnal inhabitants of this ‘forest of shadows'.

The billabong resounds with the chirping of crickets accompanied by the deep-bass croaks of mating frogs. Along the waters edge, a large mob of Simosthenurus moves down the billabongs gently slopping bank to drink. They've spent the day out across the large grassy plains to the North and need to quench their thirsts. These short-faced kangaroos belong to the family Macropodiea, which also contains the colossal kangaroo, Procoptodon .

As the mob gathers about the waters edge and lean in to take their first drink, the large-shadowy figure darts out from behind a bush, arrowing straight into the middle of the mob. It utters not a sound as it tries to close in on its prey before they can bolt for cover. Its strange gait, like a man with a pebble in his shoe, eats up the short distance between them.

The largest kangaroo lifts its head, trailing beads of water from its lower jaw as it hears the footfalls of the approaching danger. The large Simosthenurus twists and explodes into motion, pouring his immense strength into the large, single toe making up his foot. Dense thigh, calve and ankle muscles store the kinetic energy its legs receive when impacting against the ground, constricting the ligaments there until, with a snap they release, causing the toe and ankle to flex out. With this simple but energy efficient system of locomotion, the ‘Boomer' quickly reaches full speed, leaving the dark water hole far behind… others however aren't so lucky.

One juvenile female turns and is immediately blocked by other, larger panicked members of the mob. Spooked by the near impact the ‘Flyer' waits several long seconds, looking for a clear passage. Finally she sees a gap and starts to move, only to be hit by a 160-kilo bullet of muscle, teeth and razor sharp claws.

Both animals tumble to the ground with the Flyer taking the brunt of the fall. The Thylacoleo is instantly to her feet looking for the all the world like a rugby league player completing one tackle and readying for another. Quickly, the large carnivore skips lightly to the back of its victim. Previous near misses has taught the carnivore to stay away from the belly of a fallen kangaroo and it's extremely dangerous feet. A single kick from one of those flailing, powerful-clawed toes could break bones or disembowel.

Instead the marsupial lion punches out with her powerful arms, striking with her wickedly sharp thumb claws, driving them deep into the struggling animals brawny shoulder.

Its victim successfully pinned under her immense weight, the Thylacoleo bites at the Flyers neck, allowing its four massive incisors to punch deep into the soft meaty flesh. The top incisors strike bone, but instead of breaking, these thick, heavy teeth grind against the kangaroos neck vertebra, helping to grip the dying animal in place.

The Flyer continues to struggle, but the vice like grip on her neck and shoulders holds her firmly in place.

Blood fountains out of the kangaroos' neck as the huge carnivore releases and bites again, restabilising her slipping grip on the neck of her victim.

Major arteries severed, the kangaroo dies and the hunt is over.

Disentangling herself from the dead Flyer, the Thylacoleo gets to her feet and carefully scans her surroundings for danger. Assured of her safety, she flops to the ground, licking at the horrid wounds on her victims' neck. Bearing her teeth as though yawning, she bites down sideways- looking for all the world like a dog gnawing on a bone. With powerful bites with her extremely wide, bolt cutter like molars, she starts slicing her way into the dead Kangaroos' stomach and the moist, warm viscera hidden inside.

Erupting from the nearby forest, a long howl drifts across the waterhole, followed closely by the eerie appearance of glowing yellow eyes. Instantly the ‘lion' is on her feet, nervously eyeing off the tree line.

A shape darts from its dark embrace, followed by a second, then a third. These however are sleeker, smaller and seem much faster then the ‘marsupial lion'.

Further into the forests gloomy depths, more growls and ‘yalps' can be heard.

The first of the ‘dogs'-a small wolf like Thylacine - snaps its long jaws together at the Thylacoleo , trying to draw her away from the kill. It then backs away, attempting to use its' speed to keep away from the dangerous predator. Unfortunately for the Thylacine , it's too slow.

The Thylacoleo roars for the first time, challenging the thylacine as it leaps forward, slashing at the newcomer with her massive front paw. The blow slaps across the Thylacines face, the lions' large thumb claw tearing a deep gash across the ‘Tigers' head, down its face, and across it's jaw- ripping away a large chunk of its face.

The Thylacine screams in agony as it pulls away from the ‘lions' follow up strike, barely avoiding a collision with its two approaching pack mates. Their courage seems to dissipate at the sight of their alpha male whimpering away, his ruined face covered in blood. The Thylacoleo roars and mock charges them, slashing the air with her dangerous front paws, breaking the nerves of the two new Thylacines .

Behind the retreating ‘Tigers', yowls echo from the forest as the rest of their pack closes in on the Billabong. The growing din is too much for the spooked Thylacoleo who turns, reaches down and bites the dead kangaroo across the neck. Lifting the entire front end of the carcass of the ground, neck muscles bulging, the carnivore walks her meal over to a nearby tree and, with an astonishing feat of strength and athleticism, hauls the dead animal up into the tree.

Below, the bank of the enclosure fills with ‘yalping', snarling Thylacines as the entire pack gathers under the tree. Though there's no sign of the wounded alpha male, the second and third thylacines have returned, their nerves ‘regathered', showing their disproval at the Thylacoleo who, indifferently, starts to feed.

From her belly pouch, a Thylacoleo in miniature appears. Looking about as though just woken from a nap, the baby dexterously climbs over his mother and sits on the dead kangaroos chest. At 5 months old it's far too young to stomach meat yet, but it enjoys lapping at the encrusted blood covering the dead animals wounds.

Safe in their tree, mother and son feast the night away.

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