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 Scientists said on Thursday that these Australian marsupials
displayed a natural preference for using their left hand for
feeding, self-grooming and other activities. So while most people
are right-handed, most kangaroos are lefties.
Beyond providing new insight into kangaroo behavior, the research
sheds light on a unique aspect of mammalian evolution, the
researchers said.
"We found a pronounced degree of 'handedness,' comparable to that in
our species," said biologist Yegor Malashichev of Saint Petersburg
State University in Russia. "In bipedal kangaroos, in all actions
studied, there was a significant left-hand preference in the vast
majority of individuals."
The researchers said they did not expect to find hand preference in
kangaroos or other marsupials - the pouched mammals - because of
brain differences from the more common placental mammals, including
primates, the researchers said.
 "Any study that proves true 'handedness' in another bipedal
(two-footed) species contributes to the study of brain symmetry and
mammalian evolution," said wildlife ecologist Janeane Ingram of the
University of Tasmania in Australia, another of the researchers.
"Even in the scientific community, true 'handedness' was assumed to
have evolved primarily in humans and primates."
Kangaroos are herbivores with strong legs, large feet and a large
muscular tail. They use hopping as their primary means of
locomotion, and their upright stance allows them to freely use their
hands freely.
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The researchers observed two bipedal species of kangaroos and one
bipedal species of wallaby, a smaller member of the kangaroo family,
in continental Australia and the island of Tasmania off the
country's southern coast.
They found that two large, bipedal species, the eastern grey
kangaroo and the red kangaroo, exhibited left-handedness in all
tasks, including supporting the body with one forelimb in a tripedal
stance.
Red-necked wallabies, when eating from tree branches, used the left
hand, as other two kangaroo species did, to manipulate the leaves
while holding the branch with the right hand.
The researchers found less evidence for hand preference in
Australia's tree kangaroos.
The research, backed by the National Geographic Society, was
published in the journal Current Biology.
(Reporting by Will Dunham; Editing by Lisa Von Ahn)
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