Kangaroos prefer to use one of their hands over the other for everyday tasks in much the same way as we do, but with a difference: they are generally lefties, new research says.
"According to a special-assessment scale of handedness adopted for primates, kangaroos pulled down the highest grades," said lead researcher Yegor Malashichev from Saint Petersburg State University in Russia.
"We observed a remarkable consistency in responses across bipedal species in that they all prefer to use the left, not the right, hand."
In the study, researchers watched wild kangaroos in Tasmania and continental Australia.
They found that wild kangaroos show a natural preference for their left hands when performing particular actions, for instance, grooming the nose, picking a leaf or bending a tree branch, for example.
"What we observed in reality we had not initially expected," Malashichev said.
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One reason true handedness was not expected in kangaroos is because unlike other mammals, they lack the same neural circuit that bridges the left and right hemispheres of the brain.
Left-handedness was particularly apparent in eastern grey and red kangaroos. Red-necked wallabies prefer their left hand for some tasks and their right for others.
Generally, they use their left forelimb for tasks that involve fine manipulation and the right for tasks that require more physical strength.
The results should encourage more careful study of the marsupial brain, which differs from those of other mammals in many respects.
Such studies might even yield important insight into neuropsychiatric conditions, including schizophrenia and autism, the researchers said, noting links between those disorders and handedness.
The study was published in the journal Current Biology.