550-Pound Ice Age Kangaroos Could Actually Hop

Scientists just solved a prehistoric mystery that's been hopping around academic circles for years: how did 550-pound kangaroos move without shattering their ankles?

Procoptodon goliah, a massive kangaroo that disappeared around 40,000 years ago, weighed nearly three times more than today's largest kangaroos. For comparison, that's about the same as an adult grizzly bear trying to bounce on a pogo stick.

Previous studies suggested any kangaroo heavier than 350 pounds would rupture its ankle tendons if it attempted to hop. Researchers thought these Ice Age giants must have walked instead, abandoning the signature bounce that defines modern kangaroos.

But Megan Jones and her team at the University of Manchester discovered something exciting. Earlier scientists had simply scaled up modern kangaroos to understand ancient ones, missing crucial anatomical differences in the process.

The researchers examined hindlimb bones from 139 modern specimens and 40 fossils representing 63 species. What they found changed everything we thought we knew about these prehistoric giants.

The ancient kangaroos had much shorter, thicker foot bones built to absorb intense landing forces. Their heel bones were also significantly wider, providing attachment points for ankle tendons far thicker than anything seen in modern kangaroos.

Why This Inspires

This discovery reminds us that nature finds remarkable solutions to seemingly impossible challenges. A 550-pound animal successfully hopping across ancient Australia sounds absurd, yet evolution engineered the perfect biological springs to make it happen.

The thick tendons probably allowed for sudden, brief hopping bursts rather than marathon bouncing sessions. The kangaroos likely used their superpower strategically, hopping to escape marsupial lion predators or navigate rough terrain while walking most of the time.

The team also found evidence that different giant kangaroo species moved in various ways. Some walked on four limbs, while others traveled upright on two legs, suggesting these animals were far more versatile than anyone imagined.

Understanding how these creatures actually lived could finally explain why they vanished. Gilbert Price, a vertebrate paleontologist not involved in the study, notes that knowing their biology and ecology is central to understanding their extinction.

These findings prove that even animals we'll never see alive can still surprise us with their incredible adaptations.