Nine out of 10 mankind mayfavortheir ripe hands , but — according to apaperthat was recently published inCurrent Biology — most kangaroo have the opposite preference .
Researchers from Russia , Australia , and Tanzania monitored38 eastern gray kangaroos(Macropus giganteus , the world ’s second - largest coinage ) , snapping one thousand of photos in the process . Every unmarried beast disproportionately relied on itsleft handwhile “ grooming the olfactory organ , picking a leaf , or bending for a Sir Herbert Beerbohm Tree offset . ” Meanwhile , cherry kangaroo ( Macropus rufus ) displayed a similar bias , as the squad observed “ significantly more left- than right - handed individual . ”
Other marsupials have a dissimilar technique . The study also kept tabs on two idle red - necked wallaby ( Macropus rufogriseus ) populations . These critter “ always used their ripe paw for strength work , like pull up a branch down , but always land the leaves to their mouth using their left mitt , ” ecologist Janeane Ingram enjoin .
In nature , choose one appendage over another is not at all strange . Manyvertebrates have a prevalent side — elephant , for example , are either right- or left - tusked . But this is the firstprovencase of dependable handedness in non - primate beast . As Ingramexplains , that particular trait was believed to have “ evolved primarily in humankind ” and our closest relatives . kangaroo and wallabies , though , represent a very unlike mammalian mathematical group .
Given this , we may call for to amend long - standing assumptions about how , when , and why righties and lefties first appeared . Like kangaroo , the great unwashed are ramp up for getting around on two legs — which guide Yegor Malaschichev , a Saint Petersburg State University zoologist , to suspect that bipedal lifestyles are the chiefdriving forcebehind the evolution of handedness .
Interestingly , the hopping marsupials show helping hand - based favoritism to an extent matched only byHomo sapiens(even our fellow apes miss such conspicuous partiality ) . “ [ We ] are not alone in the universe,”declaresMalaschichev , “ we are two — humans and kangaroo . ”
