Researchers working with wild kangaroos in Australia have found that the marsupials have developed a strong preference for using their left hand.
Kangaroos display left-handedness
Scientists have found that while most people are right-handed, most kangaroos prefer to use their left hand for feeding, grooming and other tasks. The researchers claim that the study allows scientists to gain new insight into kangaroo behavior and also reveals a new aspect of the evolution of mammals.
“We found a pronounced degree of ‘handedness,’ comparable to that in our species,” said Yegor Malashichev, a biologist at the 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.”
At the beginning of the study, the scientists were not expecting to discover hand preference in marsupials, given differences in their brain structure when compared to other mammals such as primates.
“Any study that proves true ‘handedness’ in another bipedal (two-footed) species contributes to the study of brain symmetry and mammalian evolution,” said researcher Janeane Ingram, a wildlife ecologist at the University of Tasmania in Australia. “Even in the scientific community, true ‘handedness’ was assumed to have evolved primarily in humans and primates.”
Various species formed part of study
Kangaroos boast strong legs, large feet and a large muscular tail, features which enable them to move around primarily by hopping, and consequently keep their hands free to perform other tasks.
During the study, researchers gathered data on two bipedal species of kangaroo, and one bipedal species of wallaby, which are smaller animals from the same family as kangaroos. Animals were observed in both continental Australia and the island of Tasmania, located off the southern coast.
The eastern gray kangaroo and the red kangaroo, both of which are large, bipedal species, were found to exhibit left-handedness in all tasks. They even supported their bodies with one forelimb, in a tripedal stance, in some instances.
Red-necked wallabies and two other kangaroo species were found to use the left hand when eating from tree branches, manipulating leaves in the left and the branch in the right hand.
Australian tree kangaroos displayed less evidence of hand preference. Detailed results can be found in the journal Current Biology.