Key Points
- Scientists from the University of Manchester, University of Bristol, and University of Melbourne analysed fossil remains of giant prehistoric kangaroos weighing over 200kg.
- New study overturns assumption that hopping became mechanically impossible above 150kg, based on scaling modern kangaroos.
- Findings published today in Scientific Reports, combining living kangaroo measurements with fossil bone evidence.
- Giant kangaroos had shorter, thicker foot bones to withstand landing forces and broader heel bones for thicker ankle tendons.
- Hopping likely slower and less efficient, suited to short bursts rather than long-distance travel.
- Extinct species showed diverse locomotion: hopping mixed with bipedal walking or quadrupedal movement.
- Prehistoric Australian kangaroos had broader ecological diversity, including browsers alongside grazers.
- Lead researcher Megan Jones highlights anatomical differences from modern kangaroos.
- Dr Katrina Jones notes thicker tendons stored less elastic energy.
- Dr Robert Nudds emphasises ecological variety in prehistoric Australia.
Manchester (Manchester Mirror ) January 22, 2026 – Scientists studying fossil remains of giant prehistoric kangaroos have discovered evidence that these behemoths, weighing more than 200kg, retained the ability to hop, challenging decades-old beliefs about the biomechanical limits of such locomotion. The research, conducted by teams from The University of Manchester, University of Bristol, and University of Melbourne, reveals that these Ice Age giants were not merely scaled-up versions of today’s red kangaroos but possessed unique adaptations in their skeletal structure. Published today in the journal Scientific Reports, the study integrates measurements from living kangaroos with direct fossil analysis to demonstrate hopping feasibility.
Could Giant Kangaroos Really Hop?
Previous estimates suggested hopping became impossible above roughly 150kg, derived from extrapolating modern red kangaroo physiology, which tops out at around 90kg. As reported by lead researcher Megan Jones, Postgraduate Researcher at The University of Manchester, in the University of Manchester press release:
“Previous estimates were based on simply scaling up modern kangaroos, which may mean we miss crucial anatomical differences. Our findings show that these animals weren’t just larger versions of today’s kangaroos, they were built differently, in ways that helped them manage their enormous size.”
The team focused on two critical factors: foot bone strength and ankle tendon anchorage.
Analysis of fossils showed giant kangaroos evolved shorter, thicker foot bones capable of enduring high-impact landing forces from hops. Their heel bones, or calcanei, were notably broader, accommodating thicker tendons than those in modern species. These adaptations indicate that hopping remained viable, though modified for their massive frames.
What Limited Their Hopping Efficiency?
While structurally equipped for hopping, these giants likely did not bound across landscapes with the speed or endurance of contemporary red kangaroos. Dr Katrina Jones, Royal Society Research Fellow at The University of Bristol, explained in the same press materials: “Thicker tendons are safer, but they store less elastic energy. This likely made giant kangaroos slower and less efficient hoppers, better suited to short bursts of movement rather than long-distance travel. But hopping does not have to be extremely energy efficient to be useful, these animals probably used their hopping ability to cross rough ground quickly or to escape danger.” Thicker tendons prioritised durability over the spring-like recoil seen in smaller kangaroos, trading efficiency for safety under extreme loads.
The study’s comprehensive biomechanical assessment marks the most detailed evaluation to date, using direct fossil metrics rather than speculative scaling. This approach corrects earlier oversights, affirming that mass alone did not preclude hopping.
How Did Locomotion Vary Among Species?
Fossil evidence points to a versatile “movement repertoire” among extinct giant kangaroos, beyond pure hopping. Some species likely alternated hopping with upright bipedal walking or quadrupedal progression, adapting to diverse terrains in prehistoric Australia. This polymorphism suggests hopping served specific purposes, such as rapid evasion, rather than universal travel.
Dr Robert Nudds, Senior Lecturer in Evolution, Infection and Genomics at The University of Manchester, stated:
“Our findings contribute to the notion that kangaroos had a broader ecological diversity in prehistoric Australia than we find today, with some large species grazers like modern kangaroos while others were browsers – an ecological niche not seen in today’s large kangaroos.”
Grazers mirrored modern diets, cropping grasses, while browsers targeted leaves and shrubs, filling roles absent in current megafauna.
Why Does This Rewrite Kangaroo Evolution?
Long-held assumptions positioned giant kangaroos as non-hoppers, perhaps lumbering on all fours like oversized wombats. This study dismantles that narrative, portraying them as dynamic athletes with specialised anatomy. By merging extant kangaroo data with fossil osteology, researchers quantified tendon leverage and bone robustness, proving mechanical viability up to 250kg.
The Ice Age context amplifies significance: during Pleistocene fluctuations, these giants navigated variable climates and predators. Hopping bursts would have aided survival in Australia’s rugged interior, complementing other gaits for foraging or fleeing. Ecologically, their diversity underscores a richer prehistoric marsupial guild, contrasting today’s homogenised large kangaroo populations.
What Evidence Supports the Fossil Analysis?
Direct measurements from fossil metacarpals, metatarsals, and calcanei formed the backbone of the research. Compared against modern red kangaroos (Macropus rufus), giants exhibited proportionally stouter phalanges, resisting compressive stresses from repeated impacts. Heel breadth scaled superlinearly with size, implying tendons up to twice modern diameters—essential for stabilising jumps without fracture.
Tendon storage capacity, modelled via cross-sectional area, confirmed reduced elasticity but sufficient power output for utility. No evidence suggests complete hopping abandonment; instead, adaptations optimised for intermittent use. Images from the University of Manchester press release depict fossil hindlimbs alongside modern comparatives, visually underscoring differences in robustness.
Implications for Prehistoric Australian Fauna?
This revelation broadens understanding of megafaunal locomotion, paralleling debates on extinct proboscideans or diprotodons. Prehistoric Australia’s ecosystem supported herbivores with specialised niches: giant hopper-grazers, browsers, and possibly arboreal forms. Extinction around 40,000 years ago truncated this variety, leaving only efficient modern hoppers.
The study invites re-examination of related fossils, potentially uncovering further adaptations. It also informs biomechanics: scaling laws falter when anatomy diverges, as seen here. For palaeontologists, it validates hopping’s persistence in macropods, reshaping models of Plio-Pleistocene mobility.
Broader Context of Kangaroo Evolution?
Modern red kangaroos exemplify hopping efficiency, with slender bones and elastic tendons maximising distance. Giants prioritised strength, reflecting selective pressures from size. This dimorphism highlights evolutionary trade-offs: speed versus stability.
Dr Nudds’ commentary ties locomotion to ecology—browsers needed agility for patchy foliage, grazers for open plains. Such versatility buffered against environmental shifts, unlike rigid specialists. Today’s uniformity may stem from post-extinction bottlenecks.
