What was previously thought to be a specific with primates, handedness proved to be a specific for certain species of wild kangaroos as well.
There is a new study around that is challenging the common presumption that it was only us and great apes that display a preference for using one or the other hand for certain actions.
No longer so, when Yegor Malashichev from the Saint Petersburg State University, Russia took it upon himself to observe the behavior of kangaroos in the wild.
He set out to Australia and Tasmania, where the eastern grey kangaroos, as well as the red kangaroos and the red-neck wallabies find their natural habitats.
Here, he observed that all three species of marsupials have a predominant hand for the actions they perform. And in the majority of cases, it is the left hand.
Taken for granted with humans, handedness might be indicative of crucial evolutionary trends in other mammals. Malashichev’s findings need a more rigorous and in depth analysis of course, but they are a first stepping stone in changing text books about what we know on handedness in mammals.
Handedness seems to be an evolutionary feature of mammals that either raise from the quadruped state. However, previous studies have found that slight clues that even frogs which are walking rather than leaping show a certain type of handedness.
Marsupials like short-tailed opossums or sugar gliders have also been found to display the same preference for a certain hand, yet it is not as articulated as it is in bipedal kangaroos.
Yegor Malashichev’s research was funded by the National Geographic Committee for Research and Exploration. So, the three species under Malashichev and his team’s scrutiny were the eastern red kangaroo, its keen – the red kangaroo and the red-neck wallabies.
The first two species displayed a clear preference for using their left hand when picking their food or hanging on to a tree branch. The red-neck wallabies have more sophisticated handedness. They use the right hand for actions that require strength, while the left hand is clearly prefered for finer movements like grooming or feeding.
To test the findings even further, Malashichev set out to conduct field work in Australian and European zoos as well.
Here, the captive kangaroos did not show the same handedness as their wild brethren.
The findings will undoubtedly be taken further in subsequent studies, possibly also looking brain functions with wild kangaroos.
Image Source: warwickwildlife.com.au