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Kangaroos Are Left-Handed

Kangaroos are left-handed, according to research published in Current Biology. While the consistent favouring of one hand over the other has been considered a uniquely human characteristic, researchers at The University of Tasmania found that kangaroos display a left forelimb preference that is comparable in strength with human handedness.

PhD student Janeane Ingram observed red-necked wallabies and eastern grey kangaroos at Maria Island National Park and Mount William National Park in Tasmania, and red kangaroos at the University of NSW’s arid zone research station at Fowlers Gap, as well as the endangered Goodfellow’s tree kangaroo at zoos in Australia and Germany.

“The eastern grey and red kangaroos showed a strong preference for left forelimb use for all the observed types of behaviour,” Ingram said.

“Red-necked wallabies showed a population-level preference for left forelimb use for feeding from a bipedal position and self-grooming, as well as distinctive left and right forelimb use when bimanual feeding.

“Goodfellow’s tree kangaroo showed no preference for either the left or right forelimb for a number of observed natural behaviours.”

Ingram said that the significant difference between the land-based bipedal macropods and their tree-dwelling quadrupedal counterparts strengthened the link between posture and handedness. “Any study that proves true handedness in another bipedal species contributes to the study of brain asymmetry and mammalian evolution,” Ingram said.

“Even in the scientific community, true handedness was assumed to have evolved primarily in humans and primates, but … laterality is also obvious in how parrots hold their food or how your dog shakes hands. But these examples of lateralisation have not been proven at the population level.

“The results from our study indicate that there may be parallel evolution in handedness between placental mammals and marsupials. There are also positive benefits for the understanding of how the left and right brain hemispheres control laterality due to the potential for discovering different brain pathways in marsupials.”