During the Pleistocene, the marsupial lion, Thylacoleo carnifex, was one of Australia’s top predators. Fossil records indicate the jaguar-sized cat died out between 20,000 and 10,000 years ago (although rumors persist the “Queensland Tiger” may still survive in isolated habitats). In a new study examining Thylacoleo fossils, researchers have now found an elbow joint unique among living predatory mammals.