How Giant Kangaroos Moved Across Ancient Australia

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AAncient kangaroos were huge. A modern kangaroo weighs a maximum of 200 pounds, while some of its ancestors weighed up to 550 pounds. Given their size, paleontologists analyzed whether the ancestors would have jumped in both modern and classic kangaroo style. The consensus of studies that have extrapolated the body proportions of modern kangaroos to those of ancient kangaroos has been that their ankle and foot anatomy did not provide enough force to propel their weight in a jump.

But a study published today in Scientific reports found otherwise: their hind limbs were sufficiently robust to support jumps. Postdoctoral student Megan Jones and colleagues at the University of Manchester in the United Kingdom analyzed the hind limbs of 94 modern kangaroos and wallabies and 40 fossils. Collectively, they comprised 63 species, including several major extinct lineages of enormous Pleistocene kangaroos, such as Protemnodon sp. which inhabited Australia and New Guinea until their disappearance around 40,000 years ago.

For each species, they measured the length of the hind limb bones and the diameter of the fourth toe, which is extra long, thought to be an adaptation for rope jumping. Estimates of body weight were either taken from other published studies or inferred from bone anatomy. Then, by calculating the minimum tendon size required to withstand jumping forces without rupturing, they determined whether each species’ heel and ankle bone structure could support such a tendon.

Read more: “What Happened to the Ancient Megafauna?” »

The results showed that the hind limbs of all kangaroos, including giants, were robust enough to jump. Unlike previous studies that found jumping a giant kangaroo above a weight of around 350 pounds impossible, this study identified no strict physical limitations that would prevent it. The long metatarsals were strong enough to resist the bending movements that occur when jumping, and the ankle bones were strong enough for the insertion of the tendons needed to provide resistance when jumping.

That said, efficiency is an important consideration in wildlife relocation. Even if jumping was possible, it probably wasn’t effective for larger kangaroos. Hopping locomotion relies on the elasticity of tendons which store and release energy. The thicker tendons of giant kangaroos would have been less stretchy and, therefore, unable to store and release as much energy when jumping. The study authors hypothesize that ancient kangaroos jumped periodically as needed, for example to escape predators.

After all, giant Pleistocene kangaroos faced hyper-carnivorous predators like “marsupial lions” (Thylacoleo carnifex), whose teeth marks were found on the bones of giant kangaroos. Even the large eagles of the time, like the wedge-tailed eagle (Aquila Audax), could have attacked the kangaroos.

Thus, hopping, although it could not be sustained in massive Pleistocene kangaroos, could have provided short bursts of movement for emergency escapes. “Although jumping may not have been their primary mode of locomotion,” the researchers wrote, “our results suggest that they may be part of a broader locomotor repertoire, for example for short accelerations.”

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Main image: Nobu Tamura / Wikimedia Commons

• Devin Reese

  Published on January 22, 2026

  Devin Reese is the editor-in-chief of Natural history and a science writer based in Alexandria, Virginia.