These “hypercarnivores” had an unusual killing method.
Australia was home to lion-like marsupials of the genus Thylacoleo from around 2 million years ago up until 30,000 years ago. More closely related to a kangaroo than a large cat, these late Pleistocene hunters superficially resembled lions of today.
Though evidence suggests Thylacoleo consumed a “hypercarnivorous diet,” researchers have been uncertain about how these marsupial lions killed their prey.
In a new study, published in the journal Paleobiology, scientists studied the shape of the elbow joint of the emblematic species, Thylacoleo carnifex, originally described as “one of the fellest and most destructive of predatory beasts,” to gain clues.
They compared the marsupial lion’s elbow joint to that of other mammals. Species adapted to climbing, like the orangutan, or to manipulating food, like the kinkajou, have elbow joints that allowed for easy manoeuvrability of the forearms. On the other hand, species that specialize in running, like dogs, have joints that restrict limb movement to a back-and-forth motion.
Large cats, like tigers, have an elbow joint of intermediate shape, reflecting their use of forelimbs to grapple with their prey.
Although the marsupial lion is often compared to large cats, the shape of its elbow joint was found to be markedly different from a lion’s or tiger’s, leading the researchers to propose an alternate view on how this species manipulated its prey.
The authors write, “while large felids use their forelimbs to grapple with prey, and use their canines to hold and kill it, we propose that Thylacoleo used its large and retractable claw on the semi-opposable thumb to kill its prey, and may have used its supposedly caniniform incisors to subdue it.”
Although the species likely had a powerful bite, the researchers note that its teeth were simply not sharp enough to deliver the “killing bite.”
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