Fossil hunter Richard Owen describedThylacoleo as the "fellest and most destructive of predatory beasts." It weighed 220 pounds, had stronger jaws than an African lion, and sported wicked claws that gave it the species name carnifex : flesh-slicer. There is a reason that the marsupial lion ruled Australia's food chain 45,000 years ago.

Luckily for us, and unluckily for our ancestors, this now-extinct marsupial cave lion left us clues about its fearsome hunting capabilities. A series of claw marks etched into caves in Australia demonstrate that this fearsome predator climbed vertical wall faces with ease; indeed, one researcher notes that the lions "could have chosen longer routes to the exit with gentler slopes, but the distribution of claw marks shows that, habitually they did not." Flesh-slicers don't have time for roundabout routes.

It is worth making very clear that the marsupial lion is not a big cat. It is a marsupial, an animal most closely related to koalas as well as possums, kangaroos, and other native Australian wildlife. Thus, the marsupial lion is a striking example of convergent evolution: it is only very, very distantly related to the big cats we know and love, but similar evolutionary pressures (i.e., the pressure to be really, really good at huntin' and slicin' flesh) led it to evolve a near-identical body shape. The marsupial lion even had retractable claws, just like housecats. (If you are impressed by this convergence, check out Thylacosmilus atrox, the marsupial that looked exactly like a saber-toothed lion.)

Did the fearsome Thylacoleo hunt our ancient human relatives? Ask the guy who created this piece of cave art, a reddish painting of a man with spear buckling beneath the attack of a giant, striped, lion-shaped creature. 

Rather than asking "if" they hunted us, maybe we should ask "how." And one look at the caves where they lived-- with vertical walls decorated by slashes and claw marks -- suggests that they probably hunted us by climbing to high heights then dropping in ambush. What a time to be alive!