Giant prehistoric kangaroos may have been able to hop after all

Ancient Giants: How New Research is Rewriting Kangaroo History

Australia’s prehistoric past was home to kangaroos far larger than any living today. Recent fossil discoveries reveal some species weighed over 440 pounds, with the largest reaching nearly 550 pounds. For years, a central question puzzled paleontologists: could these massive marsupials still hop, or did their size necessitate a different mode of locomotion?

The Weight Limit Myth

Traditionally, scientists believed hopping had a strict weight limit, suggesting animals exceeding 310-350 pounds would be unable to utilize this characteristic kangaroo movement. However, groundbreaking research published in Scientific Reports is challenging this long-held assumption. This new work integrates bone mechanics, muscle force analysis, and detailed examination of fossil evidence.

Built Differently: Anatomical Adaptations

Earlier studies often scaled up the anatomy of modern kangaroos to estimate the capabilities of their extinct relatives. This approach, researchers now realize, overlooked crucial anatomical differences. “Previous estimates were based on simply scaling up modern kangaroos, which may mean we miss crucial anatomical differences,” explains Megan Jones, a postgraduate researcher at the University of Manchester. “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.”

Specifically, the study focused on two key areas: the strength of the foot bones and the resilience of the ankle tendons. Giant kangaroos possessed shorter and thicker metatarsal bones in their feet. Shorter bones experience less bending stress under force, increasing resistance to fracture. Fossil heel bones revealed broad attachment areas, indicating the presence of thick, robust tendons – particularly the gastrocnemius tendon vital for takeoff.

Muscle Power and Energy Efficiency

Calculations demonstrated that the muscle force required for hopping remained within feasible limits for these giant kangaroos. While larger muscles generate greater force, the study also highlighted a trade-off. Dr. Katrina Jones, a research fellow at the University of Bristol, notes that thicker tendons, while safer, 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,” she states. However, even less efficient hopping could have been advantageous for quickly crossing rough terrain or escaping predators.

A Flexible Movement Toolkit

The research suggests that giant kangaroos weren’t limited to a single gait. Fossil anatomy reveals a diversity of movement styles across different species. Some likely combined hopping with upright walking, while others may have moved on all fours during slower travel. This flexibility suggests adaptation to varied habitats and lifestyles.

Dietary Diversity and Ecological Roles

Movement diversity mirrored dietary diversity. Fossil teeth and skull structures indicate that some giant kangaroos grazed on grasses, similar to modern species, while others browsed on shrubs and leaves – a feeding niche not currently occupied by large kangaroos. “Our findings contribute to the notion that kangaroos had a broader ecological diversity in prehistoric Australia than we find today,” notes Dr. Robert L. Nudds, a study co-author.

Future Research and Implications

This research, as of January 23, 2026, is reshaping our understanding of kangaroo evolution and biomechanics. Further investigation into the fossil record, combined with advanced biomechanical modelling, will continue to refine our knowledge of how these magnificent creatures moved and thrived. The findings also have implications for understanding the limits of locomotion in other large mammals, both past and present.

Frequently Asked Questions

Q: How much did the largest prehistoric kangaroos weigh?
A: Some species weighed up to 550 pounds.

Q: Did giant kangaroos hop exactly like modern kangaroos?
A: No, they were likely slower and less efficient hoppers due to differences in tendon structure.

Q: What other ways did giant kangaroos move?
A: Evidence suggests they also walked upright and may have used quadrupedal locomotion.

Q: Where was this research conducted?
A: Research was conducted by scientists at the University of Manchester and the University of Bristol.

Q: When was this research published?
A: The research was published in the journal Scientific Reports in January 2026.

Did you know? The fourth metatarsal bone in the foot played a crucial role in absorbing landing forces in giant kangaroos.

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