EVEN ITS NAME is awe-inspiring. Thylacoleo carnifex – the 'flesh-eating pouched lion'. And objects of awe these fearsome predators must surely have been for Australia's first Aboriginal inhabitants, who had to fend off attacks from a frightening cadre of large and dangerous megafauna, all now long extinct.
Weighing 100kg, Thylacoleo was the largest marsupial carnivore that ever existed - it had weird, boltcutter-like teeth and one of the most powerful bites of any mammal. Unlike its distant relative the thylacine, or Tasmanian tiger, the marsupial lion had powerful arms and large thumbs with huge claws, and may have launched ambush attacks from the trees, leaping onto prey (no doubt occasionally human) from above.
We know that marsupial lions coexisted with people. The most recent fossil remains, from the species' twilight years, are possibly 40,000 years old, and date from a time when Australia's first human inhabitants were already long settled.
Megafauna in rock art
In several places, ancient rock art created by these people may depict marsupial lions, although some experts argue they are thylacines. One of these paintings - drawn in red ochre in a rock shelter near the Admiralty Gulf in the Kimberley region of Western Australia - shows an animal much thicker set than a thylacine, with a broad and blunt head, huge forelimbs and stripes along its back.
A sketch of that rock art can be seen in the background of the fantastic and evocative illustration (above) of a Thylacoleo created by Dutch palaeoillustrators (and identical twin brothers) Adrie and Alfons Kennis.
Every few years there's an interesting discovery made that increases our knowledge of the marsupial lion. Earlier this year, Flinders University palaeontologists Associate Professor Gavin Prideaux and his graduate student Sam Arman published a paper in the journal Scientific Reports, which detailed the discovery of a den that marsupial lions used to rear their young near Margaret River in WA.
Marsupial lion behaviour
Tight Entrance Cave is a limestone cavern with thousands of claw marks down the walls, which the researchers analysed digitally and determined could only have been made by Thylacoleo. More than this, they were able to show that some of the scratches were made by juveniles, and that the marks were left by a range of individuals, perhaps even hinting that these predators lived in packs and hunted cooperatively.
Scratches on steep surfaces up to 3m above the cave floor were left along a route that was the swiftest way to reach the exit hole in the roof. The experts believe this is evidence suggesting that marsupial lions were excellent climbers and would easily have been able to move through the trees in densely forested areas of Australia, possibly carrying prey onto high branches to dine on at leisure, as leopards do today.
There is only so much information that can be gleaned from the fossilised or preserved bones of animals, and trace fossils (also called ichnofossils) - such as footprints, burrows and scratch marks - can provide fascinating snippets of information about the behaviour of long-extinct and little-known creatures.
John Pickrell is the author of Flying Dinosaurs and forthcoming Weird Dinosaurs, published by NewSouth Books. Follow him on Twitter @john_pickrell.