Like humans , kangaroo prefer using one paw over the other for everyday tasks like extend to for ramification or holding on to snacks . And as it turns out , most roos are lefty ! The work , published in Current Biology , is the first study to seem at laterality in wild kangaroos and wallabies . throw a orientation is n’t as unique to humans as some researcher previously thought , although the evolution of bipedalism among marsupials and primate may have led to the trait .
No one really expected to discover “ lawful handedness ” in marsupials , since they lack the neural circuit that bridges the left and right brainpower hemisphere come up in other mammals . But previous study did bring out washy polarity of handedness in marsupials that take the air on all fours , such as sugar glider and gray short - tailed opossums .
To see if that ’s also the case for bipedal pouched mammal , a squad result by Yegor Malashichev ofSaint Petersburg State Universityobserved more than 70 animals spanning four coinage of kangaroos and wallabies in Australia and Tasmania . " What we observe in reality we did not initially expect , " Malashichev state in astatement . " But the more we observed , the more it became obvious that there is something really new and interesting in the wild . "
Wild kangaroos , they found , naturally preferred using their odd paws to perform actions such as grooming their own nose , bending a tree arm , and picking a leaf . This left - laterality was especially ostensible in easterly grey kangaroos ( Macropus giganteus , pictured above ) and red kangaroos ( Macropus rufus ) .
A red - necked wallaby fake food with one forelimb . Courtesy of Andrey Giljov and the National Geographic Society
blood-red - necked wallaby ( Macropus rufogriseus , picture just above ) , on the other handwriting , seemed to interchange between their right and exit hands , depending on the project . In general , they employ their remaining paw for tasks involving fine manipulation , such as directing stems and leaves to their mouths ; they apply their right paw for tasks that require more physical strength , like supporting branch . This air division of labor in wallaby hand - utilisation might be linked to their environmental science and feeding substance abuse . While eastern grey and scarlet kangaroos are grazers , the brush kangaroo diet includes more tree diagram and shrubs , and this browse may require specific motor demands .
And then there ’s Goodfellow ’s Sir Herbert Beerbohm Tree - kangaroo ( Dendrolagus goodfellowi ) who does n’t seem to show much of a preference . As their name suggests , they pass most of their days in trees , and they ’ve adapted a four-footed locomotion — standardized to the gliders and possums in the old studies . This supports the idea that quadrupedality hinders the locution of forelimb preferences in universe . Bipedalism may have been a catalyst for the emergence of handedness in man .
