How kangaroos got their ‘hop’

Scientists from Flinders University have found the key to understanding how kangaroos evolved to hop, and it lies in a tiny musk rat-kangaroo.

The tiny musky rat-kangaroo (Hypsiprymnodon moschatus) or “musky”, a diminutive marsupial weighing only 500g, has held the key to how larger kangaroos evolved to hop.

The musky rat-kangaroo is the last living representative of its family and part of a lineage that extends back to before kangaroos evolved their distinctive locomotor behaviour.

In a new study published in the journal ‘Australian Mammalogy’, researchers from the University of Flinders observed wild muskies in far-northern Queensland and found they use a “bound” or “half-bound” gait, with their hindfeet moving in synchrony to move. 

The muskies use a half-hop quadrupedal gait to move. Credit: Amy Tschirn

“As the only living macropod that doesn’t hop, the musky rat-kangaroo provides a crucial insight into how and when the iconic hopping form evolved,” said co-lead author Amy Tschirn. 

The muskies are still restricted to quadrupedal gaits even at very high speeds, but the half-hop gait could be a stepping stone between strictly quadrupedal movements and bipedal hopping. 

“These results signal a potential pathway to how bipedal hopping evolved in kangaroos,”  said Harvard’s Dr Peter Bishop, co-lead author of the research paper.

The tiny marsupial holds keys into the evolution of kangaroos gait. Credit: Amy Tschirn

“Perhaps it started with an ancestor that moved about on all fours like other marsupials, then an animal that bounded like the muskies, and finally evolved into the iconic hopping kangaroos we see in Australia today.”

The results found support the hypothesis that there was a functional evolutionary shift towards bipedal hopping in Macropodidae. 

The researchers say future studies will be informed by key fossil discoveries from early periods in kangaroo evolution.