President Obama, Oprah Winfrey, and Bill Gates are all lefties, and now they have unusual colleagues: kangaroos. According to a new study, some wild kangaroos tend to favor their left hands during common tasks like grooming and feeding. Yegor Malashichev, a Russian zoologist from Saint Petersburg State University and a co-author of the study, traveled to Australia to do the fieldwork. Along with his colleagues, he spent long hours observing seven species of marsupials living in the wild. Those species included red-necked wallabies, Goodfellow’s tree kangaroo, the eastern grey kangaroo, and the red kangaroo. The team watched as the animals groomed themselves, grabbed food with their paws, and leaned on their forearms while eating grass. Two species of kangaroo and one wallaby all showed the left-handed trend; some other marsupials, which walk on all fours, did not show the same bias. This new knowledge might seem pretty interesting in itself, but more importantly, the study, published in the journal Current Biology, could give scientists a better understanding of the evolution of mammals.
President Obama, Oprah Winfrey, and Bill Gates are all lefties, and now they have unusual colleagues: kangaroos.
According to a new study, some wild kangaroos tend to favor their left hands during common tasks like grooming and feeding.
Yegor Malashichev, a Russian zoologist from Saint Petersburg State University and a co-author of the study, traveled to Australia to do the fieldwork. Along with his colleagues, he spent long hours observing seven species of marsupials living in the wild. Those species included red-necked wallabies, Goodfellow’s tree kangaroo, the eastern grey kangaroo, and the red kangaroo.
The team watched as the animals groomed themselves, grabbed food with their paws, and leaned on their forearms while eating grass. Two species of kangaroo and one wallaby all showed the left-handed trend; some other marsupials, which walk on all fours, did not show the same bias.
This new knowledge might seem pretty interesting in itself, but more importantly, the study, published in the journal Current Biology, could give scientists a better understanding of the evolution of mammals.
That’s because the researchers say this is the first demonstration of population-level “handedness,” the tendency to favor one limb over another, in a species other than humans, who are mostly right-handed.
“We found a pronounced degree of handedness in an animal group only distantly related to humans,” says Malashichev. And the degree of handedness was “comparable to that in our species.”
Reflecting on this, the researchers also realized that even though humans and kangaroos aren’t all that similar, they do have one very important thing in common: both species spend a lot of time walking around on two legs. As a result, Malashichev and his colleagues suggest that moving on two legs is a triggering factor in the emergence of handedness. Animals that rely on four legs, in contrast, only show a “subtle degree of handedness,” according to Malashichev.
Favoring one hand over another used to be considered a uniquely human trait. However, Malashichev explains that over the 10 -20 years, scientists have discovered that hand preferences are “much more widespread spread in the animal kingdom than previously thought.” But he adds that for the most part, the handedness seen in non-primates is sporadic, related to specific behaviors and tasks, instead of a general way of approaching the world.
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Kangaroo image via Shutterstock.
