AUSTRALIA’s fabled ‘drop bear’ is looking a whole lot more real: A remarkable find in WA has revealed the marsupial lion could climb extraordinarily well, and raised its young in caves.

Flinders University palaeontologists have been attempting to discern more of the behaviour of this 100kg killer which became extinct about 40,000 years ago — shortly after the arrival of humans.

Much about thylacoleo carnifex remains a mystery.

It was robust. It had enormously powerful meat-scissor teeth. It also had a fiersome thumb claw — thought used to disembowel its prey.

“Could marsupial lions climb trees and leap onto unsuspecting prey? Were they solitary or social? Did adults leave young behind in dens when they went off to feed like other carnivores such as Tasmanian devils and hyenas?” asks Associate Professor Gavin Prideaux.

“We cannot travel back in time to answer these questions and one can only deduce so much from fossil skeletons.”

Fortunately, these animals left more than their bones lingering after their deaths.

SCRATCHING UP EVIDENCE

In a study published today in the Nature journal Scientific Reports, Sam Arman and Dr Prideaux reveal they have found thousands of claw marks etched on the interior of a limestone cave.

This cave, named Tight Entrance Cave, is situated near Witchcliffe, WA.

What they found adds new substance to the gradually emerging picture of thylacoleo carnifex’s physique and behaviour.

The researchers recorded and analysed the size, shape, depth and angles of the scratches.

From this the palaeontologists were able to deduce previously uncertain aspects of the marsupial lion’s biology.

For one, the large number of smaller scratches in the cave find hints at how the “drop-bear” raised its young.

CUB CLUB

It’s long been inferred that marsupial lions, like all marsupials, gave birth to highly dependent young. These could not be left alone until they were sufficiently grown.

How Thylacoleo looked after its joeys once they left the pouch had been a mystery.

“The largest of the scratch marks could only have been made by adults of T. carnifex”, the researchers say. “Many of the smaller marks were made by juveniles: they have the same form as that of the adults, but do not match claw marks made by other known cave dwellers.”

The upshot: Caves would have offered exactly the kind of cool and safe environment needed. Underground lairs also could be defended from other carnivores — such as thylacines (Tasmanian tigers) and Tasmanian devils.

But the communal cave also supports another, significant, implication:

“Given that marsupial lions were apparently adapted to apprehending and consuming large prey, it is feasible that they hunted cooperatively”, the researchers say.

This had previously been suggested by the discovery of bones bearing thylacoleo tooth-marks at other sites.

DROP-BEAR EXTRAORDINAIRE

The new evidence supports the idea that the marsupial lions were stocky yet agile predators ideally suited to bringing down giant short-faced kangaroos — and humans.

Evocative paintings of what are believed to be thylacoleos have been found in ancient Aboriginal rock art — the most dramatic of which (in the northern Kimbely) shows a beast with heavy fore-shoulders leaping at man.

But, if they lived and hunted in packs, it is also feasible for them to have tackled megafauna of the largest variety: Diprotodon optatum.

Bones of this rhino-sized wombat have been found with thylacoleo bite-marks on them.

But does thylacoleo really fit the myth of the drop-bear?

The Flinders University researchers point out that many of the claw marks were found up to 3m high above the cave’s surface, on steep inclines.

“They could have chosen longer routes to the exit with gentler slopes, but the distribution of claw marks shows that, habitually, they did not. Clearly they were excellent climbers and would easily have been able to climb trees”, Arman says.

@JamieSeidel