Study: Giant prehistoric kangaroos looked like rabbits, walked like humans

Ankle design, larger hips and knees suggest that sthenurines could put their weight on one leg at a time, an essential capability for walking on two feet.

Story highlights

  • Study finds that giant prehistoric cousin of the kangaroo walked instead of hopped
  • The creatures grew up to 7 feet tall and weighed up to 550 pounds
  • The study says sthenurines, with faces like rabbits, were "anatomically ill-suited for hopping"
A giant relative of the kangaroo with the face of a rabbit ambled around the Australian outback 100,000 years ago, according to a new study. Instead of hopping around like its modern cousin, it walked upright, one foot in front of the other, like a human.
The study, titled "Locomotion in Extinct Giant Kangaroos: Were Sthenurines Hop-Less Monsters?" and published in the journal PlOS One, said some of the creatures grew up to 7 feet tall and weighed up to 550 pounds, making them poor hoppers.
Sthenurines became extinct about 30,000 years ago.
"I don't think they could have gotten that large unless they were walking," said Christine Janis, the lead researcher and a professor of ecology and evolutionary biology at Brown University.
Members of the now extinct family of sthenurine kangaroos were likely bipedal walkers, the study said, basing its findings on a biomechanical analysis of the bones of sthenurines and other kangaroos. That analysis involved nearly 100 measurements on each of more than 140 kangaroo and wallaby skeletons.
The anatomy of sthenurines would have made them poor hoppers, the study said.
Some sthenurines may have hopped to attain fast speeds, the researchers found, but bipedal walking was likely their mode of slow speed locomotion.
Sthenurines were better suited than today's kangaroos to shift their weight on each foot as they moved forward.
"If it is not possible in terms of biomechanics to hop at very slow speeds, particularly if you are a big animal, and you cannot easily do pentapedal (four limbs and tail) locomotion, then what do you have left?" Janis said in the statement. "You've got to move somehow."
The study found that sthenurines were "anatomically ill-suited for hopping, but well suited for bearing weight on one leg at a time."
Their anatomy helped. Everything from their ankles to their proportionally bigger hip and knee joints to the shape of the pelvis shows that the sthenurines were made for walking.
It is unknown whether their reliance on walking could have contributed to their demise 30,000 years ago.
Janis said sthenurines may have struggled to elude human hunters or may have been unable to migrate far enough to find food as climate became more arid.