Australia’s largest and most ferocious land predator just got scarier.
Thylacoleo carnifex, the "marsupial lion" that stalked the continent until around 40,000 years ago, wasn't just a strong hunter with big teeth. It was an excellent climber too, new research shows, and could have ambushed prey – such as people – much like the mythical "drop bear".
Palaeontologists Sam Arman and Gavin Prideaux from Adelaide's Flinders University analysed scratch marks left by the now-extinct lions in a cave in south Western Australia and showed that not only were they able to scale walls up to three metres high, but they also reared their young in caves.
Their work was published in Scientific Reports.
T. carnifex lived from the early Pleistocene (around 1,600,000 years ago) and disappeared shortly after humans arrived on the scene, around 46,000 years ago.
Plenty of fossilised skeletons have been found, and they show the beasts were strong, stocky hunters with powerful jaws and sharp claws and teeth.
Aboriginal rock art portrays the predators even stalking humans.
But don’t be fooled by their “lion” title – T. carnifex was more closely related to today's wombats and wallabies than their savannah namesake.
And despite almost 150 years of study, big questions about their behaviour remain.
“Could marsupial lions climb trees and leap onto unsuspecting prey? Were they solitary or social? Did adults leave young behind in dens while they went off to feed like other carnivores such as Tasmanian devils and hyenas?” Prideaux asks.
“We cannot travel back in time to answer these questions and one can only deduce so much from fossil skeletons.”
So Arman and Prideaux went to the appropriately named Tight Entrance Cave near Margaret River in Western Australia, and examined thousands of claw marks in the limestone walls and bone deposits from the Pleistocene.
Claw scratches differ between species. A wombat’s claw mark, for instance, is U-shaped in cross section. A marsupial lion’s is V-shaped.
The largest scratch marks in the cave could have only been left by T. carnifex, as they were V-shaped, and no other animal was big or strong enough at the time to etch them into rock.
They also saw a few high on the walls, near an exit, signifying resident adults were strong enough to scale sheer rock.
Many smaller, lighter scratches were found further down, which they attributed to young T. carnifex.
The caves, Arman and Prideaux suggest, were safe havens for litters until they were big enough to fend for themselves: “Marsupial lions, like all marsupials, would have given birth to extremely underdeveloped young that could not be left alone until becoming at least partially weaned."
Bones from that era, also found in the cave, showed few T. carnifex bite marks. This, the researchers say, implies the marsupial lion to be a flesh-stripping specialist, much like present-day African lions, rather than a bone-gnawer, such as Tasmanian devils.
Their powerful bite, coupled with ambush abilities and meat-tearing teeth, means T. carnifex were easily able to prey on the largest marsupial – the rhinoceros-sized Diptotodon optatum – the bones of which have been found with a few marsupial lion bite marks.
Belinda Smith is a science and technology journalist in Melbourne, Australia.
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