BOB HIRSHON (host):
Unhoppy kangaroos. I’m Bob Hirshon and this is Science Update.
The iconic kangaroo is an agile beast that bounds swiftly across the Australian outback. But the marsupials actually come in many shapes and sizes, and ancient kangaroos were no exception. Brown University paleontologist Christine Janis and her team examined the fossils of short-faced kangaroos, which went extinct during the late Pleistocene period. They report in the journal PLoS ONE that the giant beasts had stiffer backs than modern kangaroos.
CHRISTINE JANIS (Brown University):
And that made me think, well, how could you hop with a stiff back like this? They had things like bigger hip joints, bigger knees, more bolstered ankles – all things that you would expect if you were striding on one leg at a time. But not if you were landing on two legs equally.
She says bipedal walking may be what allowed the largest short-faced kangaroos to grow to 500 pounds. I’m Bob Hirshon for AAAS, the science society.