Scratch marks from a limestone cave in south-western Australia have revealed that the marsupial lion, the largest marsupial carnivore of all time, was an expert climber. Most marks are believed to have been made by young lions left behind while their mother went out to hunt, but suggest the adults could also climb trees.
Many Australians, apparently concluding that the snakes, sharks, spiders and crocodiles are an insufficient deterrent to tourists, like to scare visitors with tales of “drop bears,” large carnivorous versions of koalas that leap from trees to feast on prey below. These stories may be not so much wrong as 40,000 years too late. The first arriving Aboriginal people had to cope with just such terrors in the form of Thylacoleo carnifex, the marsupial lion.
Thylacoleo carnifex skeleton. Gavin Predeaux
Samuel Arman, a PhD student at Flinders University, told IFLScience that most Australian carnivorous marsupials are part of the family that includes quolls, Tasmanian devils and the extinct Tasmanian tiger. However, “The consensus is that Thylacoleo evolved from a herbivore,” Arman said. “They are most aligned with wombats and koalas.”
The result was some seriously strange adaptations, including teeth so odd they have led to much bewilderment as to the lion's diet and lifestyle. Thylacoleo was also distinguished by its front paws, whose semi-opposable thumbs have been suggested as being used for either climbing trees or gripping onto prey.
Many fossils of Thylacoleo's bones and teeth exist, and it is frequently depicted in rock art from the first 10,000 years of human occupation of Australia. Nevertheless, it is much harder to understand the behavior of a creature so different from any still alive today than one whose morphology is a close fit with living species.
In Scientific Reports, Arman has provided new insight into the question of how Thylacoleo hunted by studying scratches on the walls of the Tight Entrance Cave, south of Perth. Some scratches may have been made by other species, but most appear to be the work of juvenile marsupial lions. “Carrying older pouch young while hunting probably constrained predatory efficiency or prey size range,” the paper noted. Arman and his supervisor Dr. Gavin Prideaux concluded that the mother lions probably left their young in the safety of the cave while hunting.
These scratch marks on the wall of a limestone cave in Western Australia prove how well the extinct marsupial lion could climb. Scale bars 10 centimeters (4 inches). Armon and Prideaux
Left to their own devices the young lions literally climbed the walls, and the height of some of the marks suggests they were very good at it. A small number of larger scratches suggests adult lions maintained their climbing ability.
Arman told IFLScience that the climbing capacity might have been a side-effect of the prey-grabbing capacity of the front feet, but it also might have been very useful in an environment with few hiding places and prey that could out-hop them. A creature weighing 80-100 kilograms (180-220 pounds) plummeting from an overhead branch would have been lethal for even the giant kangaroos of the era, but Arman said the fact the lions could climb is not conclusive evidence they used this capacity for hunting.