The majority of species of kangaroo that live on the ground exclusively show a preference for using their left hand or paw to do the majority of food gathering and grooming tasks. Kangaroo species that are tree dwelling do not display a preference for one paw or the other. Yegor Malashichev of Saint Petersburg State University in Russia is the first to show that wild kangaroos have a handedness preference like primates in the edition of the journal Current Biology.
The majority of kangaroos use their left hand for tasks that require dexterity and a deft touch and use their right paw for tasks that require higher levels of strength. Kangaroos scored higher than any other bipedal animal on tests designed to evaluate handedness in primates. Kangaroos do not have the interconnections between the hemispheres of the brain that is thought to be responsible for handedness in primates and humans. The chemical and neurological mechanism that causes kangaroo to prefer their left paw are not known.
Handedness was thought to be a primate’s only attribute at one time. Malashichev has found that a large number of mammals and some amphibians show a preference for the use of one hand or paw. Walking frogs have been shown to have a decided preference for one hand while jumping frogs do not. The discovery of a preference for one hand over the other in a large number of animals that are not primates is considered to be revolutionary. The research may provide insight into some components of human diseases including autism and schizophrenia.
