Aussie myth about ancient kangaroos busted by British team

Kangaroos are known around the world for their marvellous hopping ability. But their predecessors preferred a different method of getting around.

The background image shows modern day red kangaroos in the outback. Two are hopping and one is watching with its back to us. An inset image shows a man and a kangaroo hopping on a trampoline in New York. The image is black and white.
Modern day kangaroos are famous around the world for hopping. And it had long been thought their ancestors did the same. Source: Getty (File)

If there’s one kangaroo fact that every Aussie knows it’s that they hop. And the same had been assumed about their ancient ancestors.

But a surprising new theory from British researchers suggests we’ve got it all wrong. The protemnodon — a two-metre tall, 160kg extinct genus of giant kangaroo — usually walked on four legs.

The discovery was made after palaeontologists from Bristol University compared its fossilised arm bones to other mammals. The structure indicated it habitually put more weight on its forelimbs than modern kangaroos.

Lead author Billie Jones explained analysis of other protemnodon body parts had led other researchers to speculate it walked on four legs. They had looked closely at the creature’s ankle bone and concluded they were unsuited to hopping. Its feet were also quite short, adding weight to the theory.

Now Jones’s forearm research all but busts the hopping myth.

Protemnodons lived up to 50,000 years ago on the Australian mainland. If you search what they looked like on Google, you’ll notice that most artist renderings show them on two legs.

These older depictions now appear thoroughly outdated, like pictures of dinosaurs which show them as lumbering creatures that put weight on their curved tails.

A new drawing from the university is refreshing to see. It shows a protemnodon walking on all fours, looking more like a thylacine or possum.

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Background shows a Protemnodon skeleton at a museum in Adelaide. A graphic inset drawing compares new and old views of the Protemnodon.
New images shows how the Protemnodon is now believed to have walked. Source: Billie Jones/Science Graphic Design

Research supervisor Professor Christine Janis had previously discovered extinct sthenurines, a separate subfamily of ancient macropods, couldn’t hop and instead walked in strides. Her latest discovery continues her work in upending everything we thought we knew about ancient kangaroos.

“A study of the limb bones, and the bone proportions to each other, show that… Protemnodon, was likely a poor hopper at best, and probably moved mostly quadrupedally, perhaps bounding on all fours like tree-kangaroos do on the ground,” she said.

Hop, Walk or Bound? Limb Proportions in Kangaroos and the Probable Locomotion of the extinct genus Protemnodon’ has been published in the Journal of Mammalian Evolution.

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