Contrary to previous assumptions, scientists have now suggested that the massive, 250kg kangaroo ancestors that once roamed Australia were likely capable of hopping, despite their enormous size. This groundbreaking discovery challenges long-held beliefs about the locomotion of these prehistoric giants.
The research, led by Dr. Megan Jones of the University of Manchester, took a novel approach by studying the fossil remains of various giant kangaroo species, including the short-nosed, browsing sthenurine kangaroos that lived between 13,000 and 30,000 years ago. Unlike previous studies that extrapolated from the anatomy of modern kangaroos, this team delved directly into the physical attributes of the ancient behemoths themselves.
The findings, published in the journal Scientific Reports, reveal that these giant kangaroos possessed the necessary strength in their Achilles tendons and fourth metatarsal bones to support hopping, despite their colossal size. “They get up to 250kg, whereas the most we get today in the red kangaroo is 90kg at the absolute most,” explained Dr. Jones.
While some researchers had previously suggested that thicker tendons could have made hopping less feasible, the study counters this notion, noting that certain hopping creatures alive today, such as kangaroo rats, have relatively thick tendons yet still employ this mode of locomotion to navigate challenging terrain and evade predators.
“It is entirely possible that, as well as using hopping more infrequently, or over shorter distances, the giant kangaroos may have reduced stresses by hopping more slowly,” the authors added, suggesting these prehistoric giants may have adapted their hopping behaviour to accommodate their size.
However, Dr. Jones cautioned that the study only indicates the feasibility of hopping for these giant kangaroos, not that they necessarily did so, and did not rule out other modes of locomotion, such as the previously proposed “tiptoe” striding observed in sthenurine kangaroos.
“Any kangaroo is going to be using a combination of gaits, some for going slow, some for going fast,” noted Dr. Jones.
Dr. Gilbert Price, a palaeontologist at the University of Queensland, Australia, who was not involved in the study, praised the research for its direct focus on the fossil evidence of the giant kangaroos themselves, rather than relying on extrapolations from modern species.
“It shows that the giant kangaroos changed their proportions in ways that made hopping mechanically possible, even if it was less efficient than in modern species,” he said, while cautioning that the study did not claim these animals hopped across the landscape like their modern counterparts.
The implications of this research could also shed light on the eventual fate of the giant kangaroos. As Dr. Price noted, “If you want to understand why these animals went extinct, you first have to understand what they were actually like.” By unravelling the biomechanics of these prehistoric giants, scientists may gain crucial insights into the factors that contributed to their demise.
